| Rfc | 6545 |
|---|
| Title | Real-time Inter-network Defense (RID) |
|---|
| Author | K. Moriarty |
|---|
| Date | April 2012 |
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| Format: | TXT, HTML |
|---|
| Obsoletes | RFC6045 |
|---|
| Status: | PROPOSED STANDARD |
|---|
|
Internet Engineering Task Force (IETF) K. Moriarty
Request for Comments: 6545 EMC
Obsoletes: 6045 April 2012
Category: Standards Track
ISSN: 2070-1721
Real-time Inter-network Defense (RID)
Abstract
Security incidents, such as system compromises, worms, viruses,
phishing incidents, and denial of service, typically result in the
loss of service, data, and resources both human and system. Service
providers and Computer Security Incident Response Teams need to be
equipped and ready to assist in communicating and tracing security
incidents with tools and procedures in place before the occurrence of
an attack. Real-time Inter-network Defense (RID) outlines a
proactive inter-network communication method to facilitate sharing
incident-handling data while integrating existing detection, tracing,
source identification, and mitigation mechanisms for a complete
incident-handling solution. Combining these capabilities in a
communication system provides a way to achieve higher security levels
on networks. Policy guidelines for handling incidents are
recommended and can be agreed upon by a consortium using the security
recommendations and considerations. This document obsoletes RFC
6045.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6545.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3
1.1. Changes from RFC 6045 ......................................5
1.2. Normative and Informative ..................................6
1.3. Terminology ................................................7
2. Characteristics of Incidents ....................................7
3. Communication between CSIRTs and Service Providers ..............8
3.1. Inter-Service-Provider RID Messaging ......................10
3.2. RID Communication Topology ................................12
4. Message Formats ................................................13
4.1. RID Data Types ............................................13
4.1.1. Boolean ............................................13
4.2. RID Message Types .........................................14
5. IODEF-RID Schema ...............................................15
5.1. RIDPolicy Class ...........................................17
5.1.1. ReportSchema .......................................23
5.2. RequestStatus .............................................26
5.3. IncidentSource ............................................28
5.4. RID Name Spaces ...........................................29
5.5. Encoding ..................................................29
5.6. Including IODEF or Other XML Documents ....................29
5.6.1. Including XML Documents in RID .....................30
6. RID Messages ...................................................31
6.1. Request ...................................................31
6.2. Acknowledgement ...........................................33
6.3. Result ....................................................34
6.4. Report ....................................................36
6.5. Query .....................................................38
7. RID Communication Exchanges ....................................39
7.1. Upstream Trace Communication Flow .........................40
7.1.1. RID TraceRequest Example ...........................43
7.1.2. Acknowledgement Message Example ....................47
7.1.3. Result Message Example .............................47
7.2. Investigation Request Communication Flow ..................50
7.2.1. Investigation Request Example ......................51
7.2.2. Acknowledgement Message Example ....................53
7.3. Report Communication Flow .................................54
7.3.1. Report Example .....................................54
7.4. Query Communication Flow ..................................56
7.4.1. Query Example ......................................57
8. RID Schema Definition ..........................................58
9. Security Requirements ..........................................62
9.1. XML Digital Signatures and Encryption .....................62
9.2. Message Transport .........................................66
9.3. Public Key Infrastructure .................................67
9.3.1. Authentication .....................................68
9.3.2. Multi-Hop Request Authentication ...................69
9.4. Consortiums and Public Key Infrastructures ................70
9.5. Privacy Concerns and System Use Guidelines ................71
9.6. Sharing Profiles and Policies .............................76
10. Security Considerations .......................................77
11. Internationalization Issues ...................................77
12. IANA Considerations ...........................................78
13. Summary .......................................................80
14. References ....................................................80
14.1. Normative References .....................................80
14.2. Informative References ...................................82
Appendix A. Acknowledgements ......................................84
1. Introduction
Organizations require help from other parties to identify incidents,
mitigate malicious activity targeting their computing resources, and
to gain insight into potential threats through the sharing of
information. This coordination might entail working with a service
provider (SP) to filter attack traffic, working with an SP to resolve
a configuration issue that is unintentionally causing problems,
contacting a remote site to take down a bot network, or sharing
watch-lists of known malicious IP addresses in a consortium. The
term "SP" is to be interpreted as any type of service provider or
Computer Security Incident Response Team (CSIRT) that may be involved
in RID communications.
Incident handling involves the detection, reporting, identification,
and mitigation of an incident, whether it be a benign configuration
issue, IT incident, an infraction to a service level agreement (SLA),
system compromise, socially engineered phishing attack, or a denial-
of-service (DoS) attack, etc. When an incident is detected, the
response may include simply filing a report, notification to the
source of the incident, a request to an SP for resolution/mitigation,
or a request to locate the source. One of the more difficult cases
is that in which the source of an attack is unknown, requiring the
ability to trace the attack traffic iteratively upstream through the
network for the possibility of any further actions to take place. In
cases when accurate records of an active session between the target
or victim system and the source or attacking system are available,
the source is easy to identify.
Real-time inter-network defense (RID) outlines a proactive inter-
network communication method to facilitate sharing incident-handling
data while integrating existing detection, tracing, source
identification, and mitigation mechanisms for a complete incident
handling solution. RID provides a secure method to communicate
incident information, enabling the exchange of Incident Object
Description and Exchange Format (IODEF) [RFC5070] Extensible Markup
Language (XML) documents. RID considers security, policy, and
privacy issues related to the exchange of potentially sensitive
information, enabling SPs or organizations the options to make
appropriate decisions according to their policies. RID includes
provisions for confidentiality, integrity, and authentication.
The data in RID messages is represented in an XML [XML1.0] document
using the IODEF and RID. By following this model, integration with
other aspects for incident handling is simplified. Methods are
incorporated into the communication system to indicate what actions
need to be taken closest to the source in order to halt or mitigate
the effects of the incident or attack at hand. RID is intended to
provide a method to communicate the relevant information between
CSIRTs while being compatible with a variety of existing and possible
future detection-tracing and response approaches. Incidents may be
extended to include Information Technology (IT) incidents, where RID
enables the communication between or within providers for non-
security IT incidents.
Security and privacy considerations are of high concern since
potentially sensitive information may be passed through RID messages.
RID messaging takes advantage of XML security, privacy, and policy
information set in the RID schema. The RID schema defines
communication-specific metadata to support the communication of IODEF
documents for exchanging or tracing information regarding incidents.
RID messages are encapsulated for transport, which is defined in a
separate document [RFC6546]. The authentication, integrity, and
authorization features that RID and RID transport offer are used to
achieve a necessary level of security.
Coordinating with other CSIRTs is not strictly a technical problem.
There are numerous procedural, trust, and legal considerations that
might prevent an organization from sharing information. RID provides
information and options that can be used by organizations who must
then apply their own policies for sharing information. Organizations
must develop policies and procedures for the use of the RID protocol
and IODEF.
1.1. Changes from RFC 6045
This document contains the following changes with respect to its
predecessor [RFC6045]:
o This document is Standards Track, while [RFC6045] was published as
Informational.
o This document obsoletes [RFC6045] and moves it to Historic status.
o This document refers to the updated RID transport specification
[RFC6546], where appropriate.
o Edits reflected in this updated version of RID are primarily
improvements to the informational descriptions. The descriptions
have been updated to clarify that IODEF and RID can be used for
all types of incidents and are not limited to network security
incidents. The language has been updated to change the focus from
attacks to incidents, where appropriate. The term "network
provider" has been replaced with the more generic term of "service
provider". Several introductory informational sections have been
removed as they are not necessary for the implementation of the
protocol. The sections include:
* 1.3. Attack Types and RID Messaging,
* 2. RID Integration with Network Provider Technologies,
* 3.1. Integrating Trace Approaches, and
* 3.2. Superset of Packet Information for Traces.
o An option for a star topology has been included in an
informational section to meet current use-case requirements of
those who provide reports on incident information.
o The schema version was incremented. The schema has changed to
include IODEF [RFC5070] enveloped in RID in the RIDPolicy class
using the new ReportSchema class, to include one verified erratum,
to include additional enumerations in the Justification attribute,
to remove the AcrossNationalBoundaries region enumeration, to add
the DataWithHandlingRequirements enumeration in TrafficTypes, and
to change the name of the RequestAuthorization MsgType to
Acknowledgement. Additional text has been provided to clarify
definitions of enumerated values for some attributes. The
RequestAuthorization name was replaced with Acknowledgement to
more accurately represent the function of that message type. Text
was clarified to note the possible use of this message in response
to Query and Report messages. The attributes were fixed in the
schema to add 'lang' at the RID class level for language support.
o The TraceRequest and Investigation messages have been collapsed
into a single message with the requirement to set the MsgType
according to the functionality required for automation. The
message descriptions were identical with the exception of the
MsgType, which remains an exception depending on the desired
function. Since both of the enumerations for MsgType are each a
Request, 'Investigation' is now 'InvestigationRequest'. Content
may vary within the IODEF document for the type of Request
specified.
o The IncidentQuery message description name and MsgType enumeration
value in the schema have been changed to the more generic name of
'Query'.
o Guidance has been improved to ensure consistent implementations
and use of XML encryption to provide confidentiality based on data
markers, specifically the iodef:restriction attribute in the IODEF
and IODEF-RID schemas. The attribute may also be present in IODEF
extension schemas, where the guidance also applies. Additional
guidance and restrictions have been added for XML requirements.
o All of the normative text from the Security Considerations section
has been moved to a new section, Security Requirements.
o The order in which the RID schema is presented in Section 5 has
been changed to match the order in the IODEF-RID schema.
o Additional text has been provided to explain the content and
interactions between entities in the examples.
o Additional references have been provided to improve
interoperability with stricter guidance on the use of XML digital
signatures and encryption.
1.2. Normative and Informative
Sections 1, 2, 3, and 12 provide helpful background information and
considerations. RID systems participating in a consortium are
REQUIRED to fully implement Sections 4, 5, 6, 7, 8, 9, 10, and 11 to
prevent interoperability concerns.
1.3. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. Characteristics of Incidents
An incident may be defined as a benign configuration issue, IT
incident, an infraction to a service level agreement (SLA), system
compromise, a worm or Trojan infection, or a single- or multiple-
source denial-of-service attack. The goal of tracing a security
incident may be to identify the source or to find a point on the
network as close to the origin of the incident as possible. Incident
tracing can be used to identify the source(s) of an attack in order
to halt or mitigate the undesired behavior or to correct an
identified issue. RID messages can be communicated between entities
to report or investigate any type of incident and allow for actions
to be taken when the source of the incident or a point closer to the
source is known or has been identified. Methods to accomplish
mitigation may include remediation of a configuration issue,
filtering or rate-limiting the traffic close to the source, or taking
the host or network offline. Care must also be taken to ensure that
the systems involved in the RID communications are not abused and to
use proper analysis in determining if attack traffic is, in fact,
attack traffic at each SP involved in the investigation.
Investigating security incidents can be a difficult task since
attackers go to great lengths to obscure their identity. In the case
of a security incident, the true source might be identified through
an existing established connection to the attacker's point of origin.
However, the attacker may not connect to the compromised system for a
long period of time after the initial compromise or may access the
system through a series of compromised hosts spread across the
network. Other methods of obscuring the source may include targeting
the host with the same attack from multiple sources using both valid
and spoofed source addresses. This tactic can be used to compromise
a machine and leave the difficult task of locating the true origin
for the administrators. Attackers use many techniques, which can
vary between individuals or even organized groups of attackers.
Through analysis, the techniques may be grouped into indicators of
compromise to be shared via IODEF and RID, further assisting with the
improvement of detection capabilities. Security incidents, including
distributed denial-of-service (DDoS) attacks, can be difficult or
nearly impossible to trace because of the nature of the attack. Some
of the difficulties in investigating attacks include the following:
o the incident or attack originates from multiple sources;
o the incident may leverage social-engineering techniques or other
methods to gain access to resources and intellectual property
using what appears to be legitimate access methods such as
outbound web sessions from user systems;
o the attack may include various types of traffic meant to consume
server resources, such as a SYN flood attack without a significant
increase in bandwidth utilization;
o the type of traffic could include valid destination services,
which cannot be blocked since they are essential services to
business, such as DNS servers at an SP or HTTP requests sent to an
organization connected to the Internet;
o the attack may utilize varying types of packets including TCP,
UDP, ICMP, or other IP protocols;
o the attack may be from "zombies" or large botnets, which then
require additional searches to locate a controlling server as the
true origin of the attack;
o the attack may use a very small number of packets from any
particular source, thus making a trace after the fact nearly
impossible;
o the indicators of a compromise may be difficult to detect.
If the source(s) of an incident cannot be determined from IP address
information, it may be possible to trace the traffic based on
characteristics of the incident such as tracing the increased
bandwidth utilization or the type of packets seen by the client. In
the case of packets with spoofed source addresses, it is not a
trivial task to identify the source of an attack.
IODEF, any extensions to IODEF, and RID can be used to detail an
incident, characteristics of the incident (as it evolves), the
incident history, and communications of the incident to facilitate
the resolution and reporting of the incident.
3. Communication between CSIRTs and Service Providers
Expediting the communication between CSIRTs and SPs is essential when
responding to a security-related incident, which may cross network
access points between service providers. As a result of the urgency
involved in this inter-service-provider security incident
communication, there must be an effective system in place to
facilitate the interaction. This communication policy or method
should involve multiple means of communication to avoid a single
point of failure. Email is one way to transfer information about the
incident, packet traces, etc. However, email may not be received in
a timely fashion or be acted upon with the same urgency as a phone
call or other communication mechanism like RID.
A technical solution to trace traffic across a single SP may include
homegrown or commercial systems for which RID messaging must
accommodate the input requirements. The incident-handling system
used on the SP's backbone by the CSIRT to coordinate the trace across
the single network requires a method to accept, process, and relay
RID messages to the system, as well as to wait for responses from the
system to continue the RID request process as appropriate. In this
scenario, each service provider maintains its own system capable of
communicating via RID and integrates with a management station used
for monitoring and analysis. An alternative for providers lacking
sufficient resources may be to have a neutral third party with access
to the provider's network resources who could be used to perform the
incident-handling functions. This could be a function of a central
organization operating as a CSIRT for countries as a whole or within
a consortium that may be able to provide centralized resources.
Consortiums could consist of a federation or a group of service
providers or CSIRTs that agrees to participate in the RID
communication protocol with an agreed-upon policy and communication
protocol facilitating the secure transport of IODEF-RID XML
documents. Transport for RID messages is specified in [RFC6546].
One goal of RID is to prevent the need to permit access to other
networks' equipment. RID provides a standard messaging mechanism to
enable the communication of incident-handling information to other
providers in a consortium or in neighboring networks. The third
party mentioned above may be used in this technical solution to
assist in facilitating incident handling and possibly traceback
through smaller providers. The RID messaging mechanism may be a
logical or physical out-of-band network to ensure that the
communication is secure and unaffected by the state of the network
under attack. The two management methods would accommodate the needs
of larger providers to maintain full management of their network, and
the third-party option could be available to smaller providers who
lack the necessary human resources to perform incident-handling
operations. The first method enables the individual providers to
involve (via a notification and alerting system) their network
operations staff to authorize the continuance of a trace or other
necessary response to a RID communication request through their
network.
The network used for the communication should consist of out-of-band
or protected channels (direct communication links) or encrypted
channels dedicated to the transport of RID messages. The
communication links would be direct connections (virtual or physical)
between peers who have agreed-upon use and abuse policies through a
consortium. Consortiums might be linked through policy comparisons
and additional agreements to form a larger web or iterative network
of peers that correlates to the traffic paths available over the
larger web of networks or is based on regions and logical groups.
Contact information, IP addresses of RID systems, and other
information must be coordinated between bilateral peers by a
consortium and may use existing databases, such as the routing
arbiter. The security, configuration, and Confidence rating schemes
of the RID messaging peers must be negotiated by peers and must meet
certain overall requirements of the fully connected network
(Internet, government, education, etc.) through the peering and/or a
consortium-based agreement.
RID messaging established with clients of an provider may be
negotiated in a contract as part of a value-added service or through
a service level agreement (SLA). Further discussion is beyond the
scope of this document and may be more appropriately handled in
peering or service level agreements.
Procedures for incident handling need to be established and well
known by anyone that may be involved in incident response. The
procedures should also contain contact information for internal
escalation procedures, as well as for external assistance groups such
as a CSIRT, CERT Coordination Center (CERT/CC), Global Information
Assurance Certification (GIAC), and the U.S. Federal Bureau of
Investigations (FBI) or other assisting government organization in
the country of the investigation.
3.1. Inter-Service-Provider RID Messaging
RID provides a protocol and format that ensures interoperability
between vendors for the implementation of an incident messaging
mechanism. The messages should meet several requirements in order to
be meaningful as they traverse multiple networks. RID provides the
framework necessary for communication between networks involved in
the incident handling, possible traceback, and mitigation of a
security incident. Several message types described in Section 4.2
are necessary to facilitate the handling of a security incident. The
message types include the Report, Query, Request, Acknowledgement,
and Result message.
The Report message is used when an incident is to be filed on a RID
system or associated database, where no further action is required.
A Query message is used to request information on a particular
incident. A Request message with options set to 'TraceRequest' is
used when the source of the traffic may have been spoofed. In that
case, each SP in the upstream path who receives this Request will
issue a trace across the network to determine the upstream source of
the traffic. The Acknowledgement and Result messages are used to
communicate the status and result of a Request. The Request message
with options set to 'InvestigationRequest' may be sent to any party
assisting in an incident investigation. The InvestigationRequest
leverages the bilateral relationships or a consortium's
interconnections to mitigate or stop problematic traffic close to the
source. Routes could determine the fastest path to a known source IP
address in the case of an InvestigationRequest. A Request message
(set to 'TraceRequest' or 'InvestigationRequest') sent between RID
systems to stop traffic at the source through a bordering network
requires the information enumerated below:
1. Enough information to enable the network administrators to make a
decision about the importance of continuing the trace.
2. The incident or IP packet information needed to carry out the
trace or investigation.
3. Contact information of the origin of the RID communication. The
contact information could be provided through the Autonomous
System Number (ASN) [RFC1930] or Network Information Center (NIC)
handle information listed in the Registry for Internet Numbers or
other Internet databases.
4. Network path information to help prevent any routing loops
through the network from perpetuating a trace. If a RID system
receives a Request with MsgType set to 'TraceRequest' that
contains its own information in the path, the trace must cease
and the RID system should generate an alert to inform the network
operations staff that a tracing loop exists.
5. A unique identifier for a single attack. This identifier should
be used to correlate traces to multiple sources in a DDoS attack.
Use of the communication network and the RID protocol must be for
pre-approved, authorized purposes only. It is the responsibility of
each participating party to adhere to guidelines set forth in both a
global use policy established through the peering agreements for each
bilateral peer or agreed-upon consortium guidelines. The purpose of
such policies is to avoid abuse of the system; the policies shall be
developed by a consortium or participating entities. The global
policy may be dependent on the domain it operates under; for example,
a government network or a commercial network such as the Internet
would adhere to different guidelines to address the individual
concerns. Privacy issues must be considered in public networks such
as the Internet. Privacy issues are discussed in the Security
Requirements section, along with other requirements that must be
agreed upon by participating entities.
RID requests must be legitimate incidents and not used for purposes
such as sabotage or censorship. An example of such abuse of the
system includes a request to rate-limit legitimate traffic to prevent
information from being shared between users on the Internet
(restricting access to online versions of papers) or restricting
access from a competitor's product in order to sabotage a business.
The RID system should be configurable to either require user input or
automatically continue traces. This feature enables a network
manager to assess the available resources before continuing a Request
message set to 'InvestigationRequest' or 'TraceRequest'. If the
Confidence rating (provided in IODEF) is low, it may not be in the
provider's best interest to continue the Request with options set to
'InvestigationRequest' or 'TraceRequest'. The Confidence ratings
must adhere to the specifications for selecting the percentage used
to avoid abuse of the system. Requests must be issued by authorized
individuals from the initiating CSIRT, set forth in policy guidelines
established through peering or a SLA.
3.2. RID Communication Topology
The most basic topology for communicating RID systems is a direct
connection or a bilateral relationship as illustrated below.
___________ __________
| | | |
| RID |__________-------------___________| RID |
|_________| | SP Border | |________|
-------------
Figure 1: Direct Peer Topology
Within the consortium model, several topologies might be agreed upon
and used. One would leverage bilateral network peering relationships
of the members of the consortium. The peers for RID would match that
of routing peers, and the logical network borders would be used.
This approach may be necessary for an iterative trace where the
source is unknown. The model looks like the above diagram; however,
there may be an extensive number of interconnections of bilateral
relationships formed. Also within a consortium model, it may be
useful to establish an integrated mesh of networks to pass RID
messages. This may be beneficial when the source address is known,
and an interconnection may provide a faster route to reach the
closest upstream peer to the source of the attack traffic if direct
communication between SPs is not possible. An example is illustrated
below.
_______ _______ _______
| | | | | |
__| RID |____-------------____| RID |____-------------____| RID |__
|_____| | SP Border | |_____| | SP Border | |_____|
| ------------- ------------- |
|_______________________________________________________|
Direct connection to network that is not an immediate network peer
Figure 2: Mesh Peer Topology
By using a fully meshed model in a consortium, broadcasting RID
requests would be possible, but not advisable. By broadcasting a
request, RID peers that may not have carried the attack traffic on
their network would be asked to perform a trace for the potential of
decreasing the time in which the true source was identified. As a
result, many networks would have utilized unnecessary resources for a
Request that may have also been unnecessary.
A star topology may be desirable in instances where a peer may be a
provider of incident information. This requires trust relationships
to be established between the provider of information and each of the
consumers of that information. Examples may include country-level
CSIRTs or service providers distributing incident information to
organizations.
4. Message Formats
4.1. RID Data Types
RID is derived from the IODEF data model and inherits all of the data
types defined in the IODEF model. One data type is added by RID:
BOOLEAN.
4.1.1. Boolean
A boolean value is represented by the BOOLEAN data type.
The BOOLEAN data type is implemented as "xs:boolean" [XMLschema] in
the schema. Note that there are two lexical representations for
boolean in [XMLschema]: '1' or 'true' for TRUE and '0' or 'false' or
FALSE.
4.2. RID Message Types
The five RID message types described below MUST be implemented. RID
messages uses both the IODEF [RFC5070] and RID document, which MUST
be encapsulated for transport as specified in [RFC6546]. The
messages are generated and received on designated systems for RID
communications. Each RID message type, along with an example, is
described in the following sections. The IODEF-RID schema is
introduced in Section 5 to support the described RID message types.
1. Request. This message type is used when a request
('InvestigationRequest' or 'TraceRequest') is needed. The
purpose of the Request message (set to 'InvestigationRequest') is
to leverage the existing peer relationships in order to notify
the SP closest to the source of the valid traffic of a security-
related incident for any necessary actions to be taken. The
Request (set to 'TraceRequest') is used when the traffic has to
be traced iteratively through networks to find the source by
setting the MsgType to 'TraceRequest'. The
'InvestigationRequest' MsgType is used for all other Request
messages.
2. Acknowledgement. This message is sent to the initiating RID
system from each of the upstream provider's RID systems to
provide information on the status of a Request. The
Acknowledgement is also used to provide a reason why a Request,
Report, or Query was not accepted.
3. Result. The Result message is used to provide a final report and
the notification of actions taken for a Request. This message is
sent to the initiating CSIRT through the network of RID systems
in the path of the trace as notification that the source of the
attack was located.
4. Report. This message is used to report a security incident, for
which no action is requested. This may be used for the purpose
of correlating attack information by CSIRTs, sharing incident
information, statistics and trending information, etc.
5. Query. This message is used to request information about an
incident or incident type from a trusted system communicating via
RID. The response is provided through the Report message.
When an application receives a RID message, it must be able to
determine the type of message and parse it accordingly. The message
type is specified in the RIDPolicy class. The RIDPolicy class may
also be used by the transport protocol to facilitate the
communication of security incident data to trace, investigate, query,
or report information regarding security incidents.
5. IODEF-RID Schema
There are three classes included in the RID extension required to
facilitate RID communications. The RequestStatus class is used to
indicate the approval status of a Request message; the IncidentSource
class is used to report whether or not a source was found and to
identify the source host(s) or network(s); and the RIDPolicy class
provides information on the agreed-upon policies and specifies the
type of communication message being used.
The RID schema defines communication-specific metadata to support the
exchange of incident information in an IODEF document. The intent in
maintaining a separate schema and not using the AdditionalData
extension of IODEF is the flexibility of sending messages between RID
hosts. Since RID is a separate schema and RID messages include both
the RID and IODEF documents, the RID message acts as an envelope in
that policy and security defined at the RID message layer are applied
to both documents. One reason for maintaining separate schemas is
for flexibility, where the RIDPolicy class can be easily extracted
for use in the RID message and by the transport protocol.
The security requirements of sending incident information between
entities include the use of encryption. The RIDPolicy information is
not required to be encrypted, so separating out this data from the
IODEF XML document removes the need for decrypting and parsing the
IODEF document to determine how it should be handled at each RID
host.
The purpose of the RIDPolicy class is to specify the message type for
the receiving host, facilitate the policy needs of RID, and provide
routing information in the form of an IP address of the destination
RID system.
The security requirements and policy guidelines are discussed in
Section 9. The policy is defined between RID peers and within or
between consortiums. RIDPolicy is meant to be a tool to facilitate
the defined policies. This MUST be used in accordance with policy
set between clients, peers, consortiums, and/or regions. Security,
privacy, and confidentiality MUST be considered as specified in this
document.
The RID schema is defined as follows:
+------------------+
| RID |
+------------------+
| |
| ENUM lang |<>---{0..1}----[ RIDPolicy ]
| |
| |<>---{0..1}----[ RequestStatus ]
| |
| |<>---{0..1}----[ IncidentSource ]
+------------------+
Figure 3: The RID Schema
The aggregate classes that constitute the RID schema in the iodef-rid
namespace are as follows:
RIDPolicy
Zero or One. The RIDPolicy class is used by all message types to
facilitate policy agreements between peers, consortiums, or
federations, as well as to properly route messages.
RequestStatus
Zero or One. The RequestStatus class is used only in
Acknowledgement messages. The message reports back to the CSIRT
or SP in the Acknowledgement message to provide status on a
Request or if an error or problem occurs with the receipt or
processing of a Report, Query, or Result message.
IncidentSource
Zero or One. The IncidentSource class is used in the Result
message only. The IncidentSource provides the information on the
identified source host or network of an attack trace or
investigation.
Each of the three listed classes may be the only class included in
the RID class, hence the option for zero or one. In some cases,
RIDPolicy MAY be the only class in the RID definition when used by
the transport protocol [RFC6546], as that information should be as
small as possible and may not be encrypted. The RequestStatus
message MUST be able to stand alone without the need for an IODEF
document to facilitate the communication, limiting the data
transported to the required elements per [RFC6546].
The RID class has one attribute:
lang
One. REQUIRED. ENUM. A valid language code per [RFC5646]
constrained by the definition of "xs:language" inherited from
[XML1.0].
5.1. RIDPolicy Class
The RIDPolicy class facilitates the delivery of RID messages and is
also referenced for transport in the transport document [RFC6546].
The RIDPolicy Class includes the ability to embed an IODEF document
or XML documents that conform to schemas other than IODEF in the
ReportSchema element.
+------------------------+
| RIDPolicy |
+------------------------+
| |
| ENUM restriction |<>-------------[ Node ]
| ENUM MsgType |
| ENUM MsgDestination |<>---{0..1}----[ IncidentID ]
| ENUM ext-MsgType |
| ENUM ext-MsgDestination|<>---{1..*}----[ PolicyRegion ]
| |
| |<>---{1..*}----[ TrafficType ]
| |
| |<>---{0..1}----[ ReportSchema ]
+------------------------+
Figure 4: The RIDPolicy Class
The aggregate elements that constitute the RIDPolicy class are as
follows:
Node
One. The Node class is used to identify a host or network device,
in this case to identify the system communicating RID messages,
and the usage is determined by the MsgDestination attribute. The
base definition of this class is reused from the IODEF
specification [RFC5070], Section 3.16. See Section 11 of this
document for Internationalization considerations.
IncidentID
Zero or one. Global reference pointing back to the IncidentID
defined in the IODEF data model. The IncidentID includes the name
of the CSIRT, an incident number, and an instance of that
incident. The instance number is appended with a dash separating
the values and is used in cases for which it may be desirable to
group incidents. Examples of incidents that may be grouped
include botnets, polymorphic attacks, DDoS attacks, multiple hops
of compromised systems found during an investigation, etc.
PolicyRegion
One or many. REQUIRED. The values for the attribute "region" are
used to determine what policy area may require consideration
before a trace can be approved. The PolicyRegion may include
multiple selections from the attribute list in order to fit all
possible policy considerations when crossing regions, consortiums,
or networks.
region
One or many. REQUIRED. ENUM. The attribute region is used to
identify the expected sharing range of the incident information.
The region may be within a region or defined by existing
relationships such as those of a consortium or a client to a
service provider.
1. ClientToSP. A client initiated the request to their service
provider (SP). A client may be an individual, enterprise, or
other type of entity (government, commercial, education,
etc.). An SP may be a network, telecommunications,
infrastructure, or other type of SP where a client-to-vendor
relationship has been established. The client-to-vendor
relationship will typically have established contracts or
agreements to define expectations and trust relationships.
2. SPToClient. An SP initiated a RID request or report to a
client. A client may be an individual, enterprise, or other
type of entity (government, commercial, education, etc.). An
SP may be a network, telecommunications, infrastructure, or
other type of SP where a client-to-vendor relationship has
been established. The client-to-vendor relationship will
typically have established contracts or agreements to define
expectations and trust relationships.
3. IntraConsortium. Incident information that should have no
restrictions within the boundaries of a consortium with the
agreed-upon use and abuse guidelines. A consortium is a well-
defined group with established members and trust relationships
specific to sharing within that group. A consortium would
typically define the types of data that can be shared in
advance, define the expectations on protecting that data, as
well as have established contractual agreements. Examples of
consortiums may include industry-focused sharing communities
(financial, government, research and education, etc.) or cross
industry sharing communities (for instance, organizations
within local proximity that form a sharing group).
4. PeerToPeer. Incident information that should have no
restrictions between two peers but may require further
evaluation before continuance beyond that point with the
agreed-upon use and abuse guidelines. PeerToPeer
communications may involve any two individuals or entities
that decide to share information directly with each other.
5. BetweenConsortiums. Incident information that should have no
restrictions between consortiums that have established agreed-
upon use and abuse guidelines. BetweenConsortiums is used
when two consortiums (as defined in IntraConsortium above)
share data. The types of data that can be shared
BetweenConsortiums should be identified in their agreements
and contracts along with expectations on how that data should
be handled and protected.
6. ext-value. An escape value used to extend this attribute.
See IODEF [RFC5070], Section 5.1.
TrafficType
One or many. REQUIRED. The values for the attribute "type" are
meant to assist in determining if a trace is appropriate for the
SP receiving the request to continue the trace. Multiple values
may be selected for this element; however, where possible, it
should be restricted to one value that most accurately describes
the traffic type.
type
One or many. REQUIRED. ENUM. The attribute type is used to
identify the type of information included in the RID message or
the type of incident.
1. Attack. This option SHOULD only be selected if the traffic is
related to an information security incident or attack. The
type of attack MUST also be listed in more detail in the IODEF
Method and Impact classes for further clarification to assist
in determining if the trace can be continued ([RFC5070],
Sections 3.9 and 3.10.1).
2. Network. This option MUST only be selected when the trace is
related to network traffic or routing issues.
3. Content. This category MUST be used only in the case in which
the request is related to the content and regional
restrictions on accessing that type of content exist. This is
not malicious traffic but may be used for determining what
sources or destinations accessed certain materials available
on the Internet, including, but not limited to, news,
technology, or inappropriate content.
4. DataWithHandlingRequirements. This option is used when data
shared may have additional restrictions for handling,
protection, and processing based on the type of data and where
it resides. Regulatory or legal restrictions may be imposed
on specific types of data that could vary based on the
location, region or nation, of the data or where it
originated. The IODEF document, as well as any extensions,
included with the RID message should indicate the specific
restrictions to be considered. The use of this enumeration
flag is not legally binding.
5. AudienceRestriction. This option is used to indicate that the
message contains data that should be viewed by a restricted
audience. This setting should not be used for normal
incidents or reporting as it could slow response times. The
content may be a business-relevant notification or request.
This option MAY be used by a business partner to report or
request assistance if an incident has affected a supply chain.
This option may also be used if the content is relevant to
regulatory obligations, legal (eDiscovery), or other use cases
that require management attention.
6. Other. If this option is selected, a description of the
traffic type MUST be provided so that policy decisions can be
made to continue or stop the investigation. The information
should be provided in the IODEF message in the Expectation
class or in the History class using a HistoryItem log. This
may also be used for incident types other than information-
security-related incidents.
7. ext-value. An escape value used to extend this attribute.
See IODEF [RFC5070], Section 5.1.
ReportSchema
Zero or One. The ReportSchema class is used by the message
types that require the full IODEF schema to be included in the
RID envelope. Alternate schemas may be included if approved by
the Designated Reviewer and registered by IANA for use with
RID.
The RIDPolicy class has five attributes:
restriction
OPTIONAL. ENUM. This attribute indicates the disclosure
guidelines to which the sender expects the recipient to adhere.
This guideline provides no real security since it is the choice
of the recipient of the document to honor it. This attribute
follows the same guidelines as "restriction" used in IODEF.
MsgType
One. REQUIRED. ENUM. The type of RID message sent. The five
types of messages are described in Section 4.2 and can be noted
as one of the six selections below, where a Request is set to
either 'InvestigationRequest' or 'TraceRequest'.
1. TraceRequest. This Request message may be used to initiate
a TraceRequest or to continue a TraceRequest to an upstream
network closer to the source address of the origin of the
security incident.
2. Acknowledgement. This message is sent to the initiating
RID system from each of the upstream RID systems to provide
information on the request status in the current network.
3. Result. This message indicates that the source of the
attack was located, and the message is sent to the
initiating RID system through the RID systems in the path
of the trace.
4. InvestigationRequest. This Request message type is used
when the source of the traffic is believed to be valid.
The purpose of the InvestigationRequest is to leverage the
existing peer or consortium relationships in order to
notify the SP closest to the source of the valid traffic
that some event occurred, which may be a security-related
incident.
5. Report. This message is used to report a security incident
for which no action is requested in the IODEF Expectation
class. This may be used for the purpose of correlating
attack information by CSIRTs, gathering statistics and
trending information, etc.
6. Query. This message is used to request information from a
trusted RID system about an incident or incident type.
Additionally, there is an extension attribute to add new
enumerated values:
ext-value. An escape value used to extend this attribute. See
IODEF [RFC5070], Section 5.1.
MsgDestination
One. REQUIRED. ENUM. The destination required at this level
may either be the RID messaging system intended to receive the
request, or, in the case of a Request with MsgType set to
'InvestigationRequest', the source of the incident. In the
case of an InvestigationRequest, the RID system that can help
stop or mitigate the traffic may not be known, and the message
may have to traverse RID messaging systems by following the
routing path to the RID system closest to the source of the
attack traffic. The Node element lists either the RID system
or the IP address of the source, and the meaning of the value
in the Node element is determined by the MsgDestination
element.
1. RIDSystem. The IP address of the next upstream system
accepting RID communications is REQUIRED and is listed in
the Node element of the RIDPolicy class. If NodeName
element of the Node class is used, it contains a DNS domain
name. The originating RID system is required to check that
this domain name resolves to the IP address to which the
RID message is sent. This check may be performed in
advance of sending the message and the result saved for
future use with additional RID messages.
2. SourceOfIncident. The Address element of the Node element
contains the IP address of the incident source, and the
NodeName element of the Node class is not used. The IP
address is REQUIRED when this option is selected. The IP
address is used to determine the path of systems accepting
RID communications that will be used to find the closest
RID system to the source of an attack in which the IP
address used by the source is believed to be valid and a
Request message with MsgDestination set to
'InvestigationRequest' is used. This is not to be confused
with the IncidentSource class, as the defined value here is
from an initial Request ('InvestigationRequest' or
'TraceRequest'), not the source used in a Result message.
3. ext-value. An escape value used to extend this attribute.
All extensions shall specify the contents and meaning of
the Node element of RIDPolicy. See IODEF [RFC5070],
Section 5.1, on extensibility. If the NodeName element of
the Node class is used by an extension, NodeName may
contain an Internationalized Domain Name (IDN); see
Section 11 for applicable requirements. All extensions
SHOULD use an IP address in the Address element of the Node
class as the primary means of Node identification.
MsgType-ext
OPTIONAL. STRING. A means by which to extend the MsgType
attribute. See IODEF [RFC5070], Section 5.1.
MsgDestination-ext
OPTIONAL. STRING. A means by which to extend the
MsgDestination attribute. See IODEF [RFC5070], Section 5.1
5.1.1. ReportSchema
The ReportSchema class is an aggregate class in the RIDPolicy class.
The IODEF schema is the approved schema for inclusion in RID messages
via the ReportSchema class.
+-------------------------+
| ReportSchema |
+-------------------------+
| |
| ENUM Version |
| STRING ext-Version |<>---{1}-------[ XMLDocument ]
| ENUM XMLSchemaID |
| STRING ext-XMLSchemaID |<>---{0..1}----[ URL ]
| |
| |<>---{0..*}----[ Signature ]
| |
+-------------------------+
Figure 5: The ReportSchema Class
The elements that constitute the ReportSchema class are as follows:
XMLDocument
One. The XMLDocument is a complete XML document defined by the
iodef:ExtensionType class. This class follows the guidelines
in [RFC5070], Section 5, where the data type is set to 'xml'
and meaning is set to 'xml' to include an XML document.
URL
Zero or One. URL. A reference to the XML schema of the XML
document included. The URL data type is defined in [RFC5070],
Section 2.15, as "xs:anyURI" in the schema. The schemaLocation
for IODEF is already included in the RID schema, so this is not
necessary to include a URL for IODEF documents. The list of
registered schemas for inclusion will be maintained by IANA.
Signature
Zero to many. The Signature uses the iodef:ExtensionType class
to enable this element to contain a detached or enveloped
signature. This class follows the guidelines in [RFC5070]
Section 5 where the data type is set to 'xml' and meaning is
set to 'xml' to include an XML document. This element is used
to encapsulate the detached signature based on the iodef:
RecordItem class within the IODEF document to verify the
originator of the message or to include the enveloped
signature. If other schemas are used instead of IODEF, they
MUST provide guidance on what class to use if a detached
signature is provided for this purpose.
The ReportSchema class has four attributes:
Version
OPTIONAL. One. The Version attribute is the version number of
the specified XML schema. That schema must be an approved
version of IODEF or a schema registered with IANA for use with
RID. The IANA registry for managing schemas other than IODEF
is specified in Section 12.
ext-value. An escape value used to extend this attribute.
See IODEF [RFC5070], Section 5.1.
ext-Version
OPTIONAL. One. The ext-Version attribute is the version
number of the included XML schema. This attribute is used if a
schema other than IODEF or an IANA-registered schema that has
been added to the enumerated list for Version is included.
XMLSchemaID
OPTIONAL. One. The XMLSchemaID attribute is the identifier,
the defined namespace [XMLNames], of the XML schema of the XML
document included. The XMLSchemaID and Version specify the
format of the XMLDocument element. The only permitted values,
include the namespace for IODEF [RFC5070],
"urn:ietf:params:xml:ns:iodef-1.0", any future IETF-approved
versions of IODEF, and any namespace included in the IANA-
managed list of registered schemas for use with RID. The IANA
registry for managing schemas other than IODEF is specified in
Section 12.
ext-value. An escape value used to extend this attribute.
See IODEF [RFC5070], Section 5.1.
ext-XMLSchemaID
OPTIONAL. One. The ext-XMLSchemaID attribute is the
identifier (defined namespace) of the XML schema of the XML
document included. The ext-XMLSchemaID and ext-Version specify
the format of the XMLDocument element and are used if the
included schema is not IODEF version 1.0 or an IANA-registered
schema that has been added to the enumerated list for
XMLSchemaID.
5.2. RequestStatus
The RequestStatus class is an aggregate class in the RID class.
+--------------------------------+
| RequestStatus |
+--------------------------------+
| |
| ENUM restriction |
| ENUM AuthorizationStatus |
| ENUM Justification |
| STRING ext-AuthorizationStatus |
| STRING ext-Justification |
| |
+--------------------------------+
Figure 6: The RequestStatus Class
The RequestStatus class has five attributes:
restriction
OPTIONAL. ENUM. This attribute indicates the disclosure
guidelines to which the sender expects the recipient to adhere.
This guideline provides no real security since it is the choice
of the recipient of the document to honor it. This attribute
follows the same guidelines as "restriction" used in IODEF.
AuthorizationStatus
One. REQUIRED. ENUM. The listed values are used to provide a
response to the requesting CSIRT of the status of a Request,
Report, or Query.
1. Approved. The trace was approved and will begin in the
current SP.
2. Denied. The trace was denied in the current SP. The next
closest SP can use this message to filter traffic from the
upstream SP using the example packet to help mitigate the
effects of the attack as close to the source as possible.
The Acknowledgement message must be passed back to the
originator and a Result message must be used from the
closest SP to the source in order to indicate actions taken
in the IODEF History class.
3. Pending. Awaiting approval; a timeout period has been
reached, which resulted in this Pending status and
Acknowledgement message being generated.
4. ext-value. An escape value used to extend this attribute.
See IODEF [RFC5070], Section 5.1.
Justification
OPTIONAL. ENUM. Provides a reason for a Denied or Pending
message.
1. SystemResource. A resource issue exists on the systems
that would be involved in the request.
2. Authentication. The enveloped digital signature
[RFC3275] failed to validate.
3. AuthenticationOrigin. The detached digital signature
for the original requestor on the RecordItem entry
failed to validate.
4. Encryption. The recipient was unable to decrypt the
request, report, or query.
5. UnrecognizedFormat. The format of the provided document
was unrecognized.
6. CannotProcess. The document could not be processed.
Reasons may include legal or policy decisions.
Resolution may require communication outside of this
protocol to resolve legal or policy issues. No further
messages SHOULD be sent until resolved.
7. Other. There were other reasons this request could not
be processed.
8. ext-value. An escape value used to extend this
attribute. See IODEF [RFC5070], Section 5.1.
AuthorizationStatus-ext
OPTIONAL. STRING. A means by which to extend the
AuthorizationStatus attribute. See IODEF [RFC5070], Section
5.1.
Justification-ext
OPTIONAL. STRING. A means by which to extend the
Justification attribute. See IODEF [RFC5070], Section 5.1.
5.3. IncidentSource
The IncidentSource class is an aggregate class in the RID class.
+-------------------+
| IncidentSource |
+-------------------+
| |
| ENUM restriction |
| |<>-------------[ SourceFound ]
| |
| |<>---{0..*}----[ Node ]
| |
+-------------------+
Figure 7: The IncidentSource Class
The elements that constitute the IncidentSource class follow:
SourceFound
One. BOOLEAN. The Source class indicates if a source was
identified. If the source was identified, it is listed in the
Node element of this class.
True. Source of incident was identified.
False. Source of incident was not identified.
Node
Zero or many. The Node class is used to identify a system
identified as part of an incident. If this element is used,
the Address element of the Node element MUST contain the IP
address of the system. If the NodeName element of the Node
class is used, it contains a DNS domain name that has been
checked to ensure that it resolved to that IP address when the
check was performed. See Section 11 of this document for
internationalization considerations for NodeName. The base
definition of this class from the IODEF ([RFC5070], Section
3.16) can be expanded to include other identifiers.
The IncidentSource class has one attribute:
restriction
OPTIONAL. ENUM. This attribute indicates the disclosure
guidelines to which the sender expects the recipient to
adhere.This guideline provides no real security since it is the
choice of the recipient of the document to honor it. This
attribute follows the same guidelines as "restriction" used in
IODEF.
5.4. RID Name Spaces
The RID schema declares a namespace of
"urn:ietf:params:xml:ns:iodef-rid-2.0" and registers it per
[RFC3688]. Each IODEF-RID document MUST use the "iodef-rid-2.0"
namespace in the top-level element RID-Document. It can be
referenced as follows:
<RID-Document version="2.0" lang="en-US"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:xsi="http://www.w3c.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:ietf:params:xml:ns:iodef-rid-2.0.xsd">
5.5. Encoding
RID documents MUST begin with an XML declaration and MUST specify the
XML version used; also, the use of UTF-8 encoding is REQUIRED
([RFC3470], Section 4.4). RID conforms to all XML data encoding
conventions and constraints.
The XML declaration with no character encoding will read as follows:
<?xml version="1.0" encoding="UTF-8"?>
The following characters have special meaning in XML and MUST be
escaped with their entity reference equivalent: "&", "<", ">", "\""
(double quotation mark), and "'" (apostrophe). These entity
references are "&", "<", ">", """, and "'",
respectively.
5.6. Including IODEF or Other XML Documents
In order to support the changing activity of CSIRTS, the RID schema
can include an IODEF or other data model. The IODEF is also
extensible, enabling the schemas to evolve along with the needs of
CSIRTs. This section discusses how to include the IODEF XML document
or other XML documents to leverage the security and trust
relationships established through the use of RID. These techniques
are designed so that adding new data will not require a change to the
RID schema. This approach also supports the exchange of private XML
documents relevant only to a closed consortium. XML documents can be
included through the ReportSchema class in the RIDPolicy class. The
XMLDocument attribute is set to 'xml' to allow for the inclusion of
full IODEF or other XML documents. The following guidelines MUST be
followed:
1. The included schema MUST define a separate namespace, such as the
declared namespace for IODEF of
"urn:ietf:params:xml:ns:iodef-1.0".
2. When a parser encounters an included XML document it does not
understand, the included document MUST be ignored (and not
processed), but the remainder of the document MUST be processed.
Parsers will be able to identify the XML documents for which they
have no processing logic through the namespace declaration.
Parsers that encounter an unrecognized element in a namespace
that they do support SHOULD reject the document as a syntax
error.
3. Implementations SHOULD NOT download schemas at runtime due to the
security implications, and included documents MUST NOT be
required to provide a resolvable location of their schema.
The examples included in Section 7 demonstrate how an IODEF document
is included. The included schema of IODEF is represented in
ReportSchema as follows:
Version: "1.0"
XMLSchemaID: "urn:ietf:params:xml:ns:iodef-1.0"
URL: "http://www.iana.org/assignments/xml-registry/schema/
iodef-1.0.xsd"
The URL is optionally included for IODEF since it is already in the
RID schema, and the schemaLocation is defined.
5.6.1. Including XML Documents in RID
XML schemas may be registered for inclusion in a RID message. This
may include schemas other than IODEF or updated versions of IODEF.
The registered IANA information for additional schemas MUST include
the specification name, version, specification Uniform Resource
Identifier (URI), and namespace. The following provides an example
of the necessary information for additional schemas beyond IODEF.
Example Name (XXXX)
Schema Name: XXXX_1.1
Version: 1.1
Namespace: <registered namespace>
Specification URI: http://www.example.com/XXXX
The version attribute of the ReportSchema class is populated with the
approved versions of IODEF or any additional schemas registered by
IANA; see Section 12.
The XMLSchemaID of the ReportSchema class is populated with the
namespace of the included schema. The attribute enumeration values
include the namespace for IODEF and any schema registered by IANA;
see Section 12.
The URL element of the ReportSchema class is populated with the
Specification URI value of the included schema.
6. RID Messages
The IODEF model is followed as specified in [RFC5070] for each of the
RID message types. The RID schema is used in combination with IODEF
documents to facilitate RID communications. Each message type varies
slightly in format and purpose; hence, the requirements vary and are
specified for each. All classes, elements, attributes, etc., that
are defined in the IODEF-Document are valid in the context of a RID
message; however, some listed as optional in IODEF are mandatory for
RID as listed for each message type. The IODEF model MUST be fully
implemented for RID messages that include IODEF payloads to ensure
proper parsing of those messages.
Note: The implementation of RID may automate the ability to fill in
the content required for each message type from packet input,
incident data, situational awareness information, or default values
such as those used in the EventData class.
6.1. Request
Description: This message type is used to request assistance in a
computer security investigation. The investigation request may be
directed to another party that can assist with forensics and continue
the investigation (the incident may have originated on the SP network
to which the Request was sent), or it may be directed to an SP to
trace the traffic from an unknown source. The Request message with
MsgType set to 'InvestigationRequest' may leverage the existing
bilateral peer relationships in order to notify the SP closest to the
source of the valid traffic that some event occurred, which may be a
security-related incident. A Request message with the MsgType set to
'TraceRequest' may be sent to an upstream peer to trace back through
the network to locate the source of malicious traffic. The following
information is REQUIRED for Request messages and is provided through
the following data structures:
RID Information:
RIDPolicy
RID message type, IncidentID, and destination policy
information
IODEF Information:
Timestamps (DetectTime, StartTime, EndTime, ReportTime).
Incident Identifier (Incident class, IncidentID).
Confidence rating of security incident (Impact and Confidence
class).
System class is used to list both the Source and Destination.
Expectation class should be used to request any specific actions
to be taken close to the source.
Path information of nested RID systems, beginning with the request
originator used in the trace using IODEF EventData with category
set to 'infrastructure'.
Event, Record, and RecordItem classes to include example packets
and other information related to the incident. Note: Event
information included here requires a second instance of EventData
in addition to that used to convey SP path contact information.
Standards for encryption and digital signatures [RFC3275] [XMLsig]
[XMLencrypt]:
Digital signature from initiating CSIRT or provider system sending
the RID message, passed to all systems receiving the Request using
a detached XML digital signature on a RecordItem entry, placed in
an instance of the Signature element.
Digital signature of sending CSIRT or SP for authenticity of the
RID message, from the CSIRT or provider creating this message
using an enveloped XML digital signature on the IODEF document,
placed in an instance of the Signature element.
XML encryption as required by policy, agreements, and data
markers.
Security requirements include the ability to encrypt [XMLencrypt] the
contents of the Request message using the public key of the
destination RID system. The incident number increases whether the
Request message has the MsgDestination set to 'InvestigationRequest'
or 'TraceRequest' in order to ensure uniqueness within the system.
The relaying peers also append their Autonomous System (AS) or RID
system information using the path information as the Request message
was relayed through SPs. This enables the response (Result message)
to utilize the same path and trust relationships for the return
message, indicating any actions taken. The request is recorded in
the state tables of both the initiating and destination SP RID
systems. The destination SP is responsible for any actions taken as
a result of the request in adherence to any service level agreements
or policies. The SP MUST confirm that the traffic actually
originated from the suspected system before taking any action and
confirm the reason for the request. The request may be sent directly
to a known RID system or routed by the source address of the attack
using the MsgDestination of RIDPolicy set to 'SourceOfIncident'.
Note: Any intermediate parties in a TraceRequest MUST be able to view
RIDPolicy information of responding message types in order to
properly direct RID messages.
A DDoS attack can have many sources, resulting in multiple traces to
locate the sources of the attack. It may be valid to continue
multiple traces for a single attack. The path information enables
the administrators to determine if the exact trace already passed
through a single network. The Incident Identifier must also be used
to identify multiple Requests from a single incident. If a single
Request results in divergent paths of Requests, a separate instance
number MUST be used under the same IncidentID. The IncidentID
instance number of IODEF can be used to correlate related incident
data that is part of a larger incident.
6.2. Acknowledgement
Description: The Acknowledgement is also used to provide a status to
any message type and to provide a Justification if the message could
not be processed for any reason. This message is sent to the
initiating RID system from the next upstream provider's application
or system designated for accepting RID communications to provide
information on the request status in the current SP.
The following information is REQUIRED for Acknowledgement messages
and is provided through the following data structures:
RID Information:
RIDPolicy
RID message type, IncidentID, and destination policy
information
RequestStatus class:
Status of Request
Standards for encryption and digital signatures [RFC3275], [XMLsig],
[XMLencrypt]:
Digital signature of responding CSIRT or provider for authenticity
of Trace Status Message, from the CSIRT or provider creating this
message using an enveloped XML digital signature.
XML encryption as required by policy, agreements, and data
markers.
A message is sent back to the initiating CSIRT or provider's system;
it accepts RID communications of the trace as status notification.
This message verifies that the next RID system in the path has
received the message from the previous system in the path. This
message also verifies that the trace is now continuing, has stopped,
or is pending in the next upstream CSIRT or provider's RID system.
The Pending status is automatically generated after a 2-minute
timeout without system-predefined or administrator action to approve
or disapprove the trace continuance. If a Request is denied, the
originator and sending peer (if they are not the same) MUST both
receive the message. This provides the sending peer with the option
to take action to stop or mitigate the traffic as close to the source
as possible.
6.3. Result
Description: This message indicates that the trace or investigation
has been completed and provides the result. The Result message
includes information on whether or not a source was found, and the
source information is provided through the IncidentSource class. The
Result information MUST go back to the originating RID system that
began the investigation or trace. A provider may use any number of
incident-handling data sources to ascertain the true source of an
attack. All of the possible information sources may or may not be
readily tied into the RID communications system.
The following information is REQUIRED for Result messages and will be
provided through the following data structures:
RID Information:
RIDPolicy
RID message type, IncidentID, and destination policy
information
Incident Source
The IncidentSource class of the RID schema is used to note
if a source was identified and provide the source
address(es) or other Node information.
IODEF Information:
Timestamps (DetectTime, StartTime, EndTime, ReportTime).
Incident Identifier (Incident class, IncidentID).
Trace number is used for multiple traces of a single
incident; it MUST be included if the response is specific to
an instance of an incident.
Confidence rating of security incident (Impact and Confidence
class).
System class is used to list both the Source and Destination
Information used in the attack and must note if the traffic is
spoofed, thus requiring in RID an upstream Request set to
'TraceRequest'.
History class "atype" attribute is used to note any actions
taken.
History class also notes any other background information
including notes about the Confidence level or rating of the
result information.
Path information of nested RID systems, beginning with the
request originator used in the trace using IODEF EventData with
category set to 'infrastructure'. The last SP listed is the SP
that located the source of the traffic (the provider sending
the Result message).
Event, Record, and RecordItem classes to include example
packets and other information related to the incident
(optional). Note: Event information included here requires a
second instance of EventData in addition to that used to convey
SP path contact information.
Standards for encryption and digital signatures [RFC3275],
[XMLsig], [XMLencrypt]:
Digital signature of source CSIRT or provider for authenticity
of Result message, from the CSIRT or provider creating this
message using an enveloped XML digital signature.
XML encryption as required by policy, agreements, and data
markers.
A message is sent back to the initiating CSIRT or provider's RID
system to notify the CSIRT that the source has been located. The
actual source information may or may not be included, depending on
the policy of the network in which the client or host is attached.
Any action taken by the SP to act upon the discovery of the source of
a trace should be included. The SP may be able to automate the
adjustment of filters at their border router to block outbound access
for the machine(s) discovered as a part of the attack. The filters
may be comprehensive and block all Internet access until the host has
taken the appropriate action to resolve any security issues. The SP
may be limited in their options for filtering due to agreements or
other restrictions resulting in less comprehensive filters, such as
rate-limiting the ingress traffic as close to the source as possible.
Security and privacy requirements discussed in Section 9 MUST be
taken into account.
Note: The History class has been expanded in IODEF to accommodate all
of the possible actions taken as a result of a RID Request using the
"iodef:atype", or action type, attribute. The History class should
be used to note all actions taken close to the source of a trace or
incident using the most appropriate option for the type of action
along with a description. The "atype" attribute in the Expectation
class can also be used to request an appropriate action when a
Request is made.
6.4. Report
Description: This message or document is sent to a RID system to
provide a report of a security incident. This message does not
require any actions to be taken, except to file the report on the
receiving RID system or associated database.
The following information is REQUIRED for Report messages and will be
provided through the following data structures:
RID Information:
RIDPolicy RID message type, IncidentID, and destination policy
information
The following data is RECOMMENDED if available and can be provided
through the following data structures:
IODEF Information:
Timestamps (DetectTime, StartTime, EndTime, ReportTime).
Incident Identifier (Incident class, IncidentID).
Trace number is used for multiple traces of a single
incident; it MUST be included if the Report is specific to
an instance of an incident.
Confidence rating of security incident (Impact and Confidence
class).
System class is used to list both the Source and Destination
Information used in the attack.
Event, Record, and RecordItem classes are used to include
example packets and other information related to the incident
(optional).
Standards for encryption and digital signatures [RFC3275],
[XMLsig], [XMLencrypt]:
Digital signature from initiating RID system, passed to all
systems receiving the report using an enveloped XML digital
signature, placed in an instance of the Signature element.
XML encryption as required by policy, agreements, and data
markers.
Security requirements include the ability to encrypt [XMLencrypt] the
contents of the Report message using the public key of the
destination RID system. Senders of a Report message should note that
the information may be used to correlate security incident
information for the purpose of trending, pattern detection, etc., and
may be shared with other parties unless otherwise agreed upon with
the receiving RID system. Therefore, sending parties of a Report
message may obfuscate or remove destination addresses or other
sensitive information before sending a Report message. A Report
message may be sent either to file an incident report or to respond
to a Query, and data sensitivity must be considered in both cases.
The SP path information is not necessary for this message, as it will
be communicated directly between two trusted RID systems.
6.5. Query
Description: The Query message is used to request incident
information from a trusted RID system. The request can include the
incident number, if known, or detailed information about the
incident. If the incident number is known, the Report message
containing the incident information can easily be returned to the
trusted requestor using automated methods. If an example packet or
other unique information is included in the Query, the return report
may be automated; otherwise, analyst intervention may be required.
The following information is REQUIRED for a Query message and is
provided through the following data structures:
RID Information:
RIDPolicy
RID message type, IncidentID, and destination policy
information
IODEF Information (optional):
Timestamps (DetectTime, StartTime, EndTime, ReportTime).
Incident Identifier (Incident class, IncidentID).
Trace number is used for multiple traces of a single
incident; it MUST be included if the Query is an instance of
an incident.
Confidence rating of security incident (Impact and Confidence
class).
System class is used to list both the Source and Destination
Information used in the attack.
Event, Record, and RecordItem classes are used to include
example packets and other information related to the incident
(optional).
Standards for encryption and digital signatures [RFC3275],
[XMLsig], [XMLencrypt]:
Digital signature from the CSIRT or SP initiating the RID
message, passed to all systems receiving the Query using an
enveloped XML digital signature, placed in an instance of the
Signature element.
XML encryption as required by policy, agreements, and data
markers.
The proper response to the Query message is a Report message.
Multiple incidents may be returned for a single query if an incident
type is requested. In this case, the receiving system sends an IODEF
document containing multiple incidents or all instances of an
incident. The system sending the reply may preset a limit to the
number of documents returned in one report. The recommended limit is
5, to prevent the documents from becoming too large. Other transfer
methods may be better suited than RID for large transfers of data.
The Confidence rating may be used in the Query message to select only
incidents with an equal or higher Confidence rating than what is
specified. This may be used for cases when information is gathered
on a type of incident but not on specifics about a single incident.
Source and Destination Information may not be needed if the Query is
intended to gather data about a specific type of incident.
7. RID Communication Exchanges
The following section outlines the communication flows for RID and
also provides examples of messages.
The possible set of message exchanges include:
o Request: Asynchronous Request for assistance and/or action to be
taken, MAY involve multiple systems and iterative Requests
MsgType set to 'InvestigationRequest' or 'TraceRequest'
Possible responses:
+ Acknowledgement (OPTIONAL for InvestigationRequest)
+ Result (REQUIRED unless Acknowledgement was set to 'no')
+ Report (OPTIONAL; zero or more; Report can be sent
unsolicited)
o Query: Synchronous request for information
MsgType set to 'Query'
Possible responses:
+ Acknowledgement (OPTIONAL if yes; REQUIRED if no Report will
be sent)
+ Report (REQUIRED unless Acknowledgement was set to 'no')
o Report: Asynchronous information report; may be pushed to systems
or may be a response to a Query
MsgType set to 'Report'
Possible responses:
+ Acknowledgement (OPTIONAL)
Processing considerations for the IODEF document and any IODEF
included elements or attributes MUST follow the guidelines specified
in [RFC5070], Section 4. [RFC3023] and [RFC3470] specify
requirements and best practices for the use of XML in IETF
application protocols. RID and IODEF documents MUST be well-formed
(see [RFC3470], Section 4.1) and MUST be validated against the
appropriate schema. Internal or external DTD subsets are prohibited
in RID; see [RFC3023], Section 3.
Comments can be ignored by conform ant processors for RID or IODEF
documents (see [RFC3470], Section 4.6) and are included below for
informational purposes only. The first example demonstrates the use
of a detached digital signature. Subsequent examples do not include
the detached signature required for some message types. The
signature is applied after the message is created as demonstrated in
the first example.
Note: For each example listed below, [RFC5735] addresses were used.
Assume that each IP address listed is actually a separate network
range held by different SPs. Addresses were used from /27 network
ranges.
7.1. Upstream Trace Communication Flow
The diagram below outlines the RID Request communication flow for a
TraceRequest between RID systems on different networks tracing an
attack. The Request message with MsgDestination set to
'TraceRequest' is represented in the diagram by "TraceRequest".
SP-1, SP-2, and SP-3 represent service providers that are involved in
the example trace communication flow.
Attack Dest SP-1 SP-2 SP-3 Attack Src
1. Attack | Attack
reported | detected
2. Initiate trace
3. Locate origin
through
upstream SP
4. o---TraceRequest----->
5. Trace
Initiated
6. <---Acknowledgement--o
7. Locate origin
through
upstream SP
8. o---TraceRequest--->
9. Trace Initiated
10. <----------Acknowledgement----o
<-Acknowledgement-o
11. Locate attack
source on network X
12. <------------Result----------------o
13. o- - - - -Acknowledgement- - - - - >
Figure 8: TraceRequest Communication Flow
Before a trace is initiated, the RID system should verify that an
instance of the trace or a similar request is not active. The traces
may be resource intensive; therefore, providers need to be able to
detect potential abuse of the system or unintentional resource
drains. Information such as the Source and Destination Information,
associated packets, and the incident may be desirable to maintain for
a period of time determined by administrators.
The communication flow demonstrates that an Acknowledgement message
is sent to both the downstream peer and the original requestor. If a
Request in a traceback is denied, the downstream peer has the option
to take an action and respond with a Result message. The originator
of the request may follow up with the downstream peer of the SP
involved using a Request with the MsgType set to
'InvestigationRequest' to ensure that an action is taken if no
response is received. Nothing precludes the originator of the
request from initiating a new Request with the MsgType set to
'TraceRequest' thereby bypassing the SP that denied the request, if a
trace is needed beyond that point. Another option may be for the
initiator to send an 'InvestigationRequest' to an SP upstream of the
SP that denied the request. This action assumes enough information
was gathered to discern the true source of the attack traffic from
the incident-handling information.
The proper response to a TraceRequest is an Acknowledgement message.
The Acknowledgement message lets the requestor know if the trace will
continue through the next upstream network. If there is a problem
with the request, such as a failure to validate the digital signature
or decrypt the request, an Acknowledgement message MUST be sent to
the requestor and the downstream peer (if they are not one and the
same) providing the reason why the message could not be processed.
Assuming that the trace continued, additional TraceRequests with the
response of an Acknowledgement message would occur, thereby passing
the request upstream in the path to the source of the traffic related
to the incident. Once a source is found, a Result message is sent to
the originator of the trace, as determined by the SP path information
provided through the document instance of EventData, where contact is
set to 'infrastructure'. The SP path information is also used when
sending the Acknowledgement messages to the first entry (the trace
originator) and the last nested entry (the downstream peer). The
Result message is encrypted [XMLencrypt] for the originator providing
information about the incident source and any actions taken. If the
originator fails to decrypt or authenticate the Result message, an
Acknowledgement message is sent in response; otherwise, no return
message is sent. The final Acknowledgement to the Result message is
depicted as optional in the diagram above. If an Acknowledgement
message is sent with the RequestStatus set to Denied, a downstream
peer receiving this message may choose to take action to stop or
mitigate the traffic at that point in the network, as close to the
source as possible. If the downstream peer chooses this option, it
would send a Result message to the trace originator.
7.1.1. RID TraceRequest Example
The example listed is of a Request message with MsgDestination set to
'TraceRequest' based on the incident report example from the IODEF
document. The RID classes were included as appropriate for a Request
message of this type using the RIDPolicy class. The example given is
that of a CSIRT reporting a DoS attack in progress to the upstream
SP. The request asks the next SP to continue the trace and have the
traffic mitigated closer to the source of the traffic. The example
Request message is the first step of a TraceRequest as depicted in
the previous diagram, where 'Attack Dest' is represented by
192.0.2.67 (and SP-1). The 'Attack Src' is later identified in the
Result message example as 192.0.2.37 and initially as tracing closer
to 192.0.2.35. SP-1 is identified in the Request as CSIRT-FOR-OUR-
DOMAIN, and SP-2 is identified in the RID document for the Request as
the 'RIDSystem' in 'MsgDestination' as 192.0.2.3 using the Node
class. SP-3 is later used in the Result message and the
administrator is identified as 'Admin-contact@10.1.1.2' as they
searched for 192.0.2.35; the administrator may be different than the
constituency contact (an additional Request with MsgDestination set
to 'TraceRequest' occurred between SP-2 to SP-3 that is not
included). SP-3 is the service provider for 192.0.2.32/27 and was
able to take the action to rate-limit their traffic. The SP-1, SP-2,
and SP-3 information would be replaced with the appropriate (and
valid) email and other contact information in real usages. The Node
class enables multiple methods to identify a system, such as a fully
qualified domain name or the IP address to be provided for the SP.
Any mapping of existing relationships from the SP Node information to
the name, contact, digital signature verification information and
other identifying or trust information is provided at the application
layer to support end users of the incident management system. A
packet is provided in this example to enable any traces to be
performed by SP-2 and SP-3 to perform traces to the attack source
before taking the requested action to 'rate-limit' the traffic. The
subnet of 192.0.2.0 uses a 27-bit mask in the examples below.
In the following example, use of [XMLsig] to generate digital
signatures follows the guidance of [XMLsig] 1.0. Version 1.1 of
[XMLsig] supports additional digest algorithms. Reference [RFC4051]
for URIs intended for use with XML digital signatures, encryption,
and canonicalization. SHA-1 SHOULD NOT be used; see [RFC6194] for
further details.
Note: Due to the limit of 72 characters per line, some line breaks
were added in the examples and schemas in this document.
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<iodef-rid:RID lang="en-US"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:ietf:params:xml:ns:iodef-rid-2.0">
<iodef-rid:RIDPolicy MsgDestination="RIDSystem" MsgType="TraceRequest">
<iodef-rid:PolicyRegion region="IntraConsortium"/>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.3</iodef:Address>
</iodef:Node>
<iodef-rid:TrafficType type="Attack"/>
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#207-1
</iodef:IncidentID>
<!-- IODEF-Document included in RID -->
<iodef-rid:ReportSchema Version="1.0">
<iodef-rid:XMLDocument dtype="xml" meaning="xml">
<IODEF-Document lang="en">
<iodef:Incident purpose="traceback" restriction="need-to-know">
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#207-1
</iodef:IncidentID>
<iodef:DetectTime>2004-02-02T22:49:24+00:00</iodef:DetectTime>
<iodef:StartTime>2004-02-02T22:19:24+00:00</iodef:StartTime>
<iodef:ReportTime>2004-02-02T23:20:24+00:00</iodef:ReportTime>
<iodef:Description>
Host involved in DoS attack
</iodef:Description>
<iodef:Assessment>
<iodef:Impact completion="failed" severity="low"
type="dos"/>
</iodef:Assessment>
<iodef:Contact role="creator" type="organization">
<iodef:ContactName>Constituency-contact for 192.0.2.35
</iodef:ContactName>
<iodef:Email>Constituency-contact@192.0.2.35</iodef:Email>
</iodef:Contact>
<iodef:EventData>
<iodef:Flow>
<iodef:System category="source">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.35
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>38765</iodef:Port>
</iodef:Service>
</iodef:System>
<iodef:System category="target">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.67
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>80</iodef:Port>
</iodef:Service>
</iodef:System>
</iodef:Flow>
<iodef:Expectation action="rate-limit-host" severity="high">
<iodef:Description>
Rate-limit traffic close to source
</iodef:Description>
</iodef:Expectation>
<iodef:Record>
<iodef:RecordData>
<iodef:Description>
The IPv4 packet included was used in the described attack
</iodef:Description>
<iodef:RecordItem dtype="ipv4-packet">450000522ad9
0000ff06c41fc0a801020a010102976d0050103e020810d9
4a1350021000ad6700005468616e6b20796f7520666f7220
6361726566756c6c792072656164696e6720746869732052
46432e0a
</iodef:RecordItem>
</iodef:RecordData>
</iodef:Record>
</iodef:EventData>
<iodef:History>
<iodef:HistoryItem action="rate-limit-host">
<iodef:DateTime>
2001-09-14T08:19:01+00:00
</iodef:DateTime>
<iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
CSIRT-FOR-OUR-DOMAIN#207-1
</iodef:IncidentID>
<iodef:Description>
Notification sent to next upstream SP closer to 192.0.2.35
</iodef:Description>
</iodef:HistoryItem>
</iodef:History>
</iodef:Incident>
</IODEF-Document>
</iodef-rid:XMLDocument>
<!-- End of IODEF-Document included in RID -->
<!-- Start of detached XML signature included in RID -->
<iodef-rid:Signature dtype="xml" meaning="xml">
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#"
Id="dsig-123456">
<SignedInfo>
<CanonicalizationMethod
Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
<SignatureMethod
Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
<Reference URI="">
<Transforms>
<Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
<Transform Algorithm="http://www.w3.org/2002/06/xmldsig-filter2">
<XPath xmlns="http://www.w3.org/2002/06/xmldsig-filter2"
xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"
xmlns:dsig-trans="http://www.w3.org/2002/06/xmldsig-filter2"
Filter="intersect">
//dsig:Signature[@Id = 'dsig-123456']/
ancestor::iodef-rid:ReportSchema/
iodef-rid:XMLDocument/IODEF-Document[1]/iodef:Incident[1]/
iodef:EventData[1]/iodef:Record[1]/iodef:RecordData[1]/
iodef:RecordItem[1]</XPath></Transform></Transforms>
<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
<DigestValue>
NQuIhPjdZuZJnPi/hW62dwJT1dR+vqcZV8mpemCVN5g=
</DigestValue>
</Reference></SignedInfo>
<SignatureValue>
lnq/ePQ4AVpxCR0ifCp9sMsW0r/AdT3C2GR/zaN1V+hZ/NApOygUjMzTCQnx+RvGPNkO/RVq
BEIDgZQUEnQZn/uSbmr0tQ6xpBfaxF1DCosLgiZy+2jFzpXrwoN/jHNgtxR/9QLW9mZ+I7V6
LEEJ73Kut+d0naTGHlyi64ab2PqsVuRXQ4pXUKbhMkhzeTIqvFLK93KGfsIMd6Cb+n2u/ABy
Lkc+gflJYUWVP4DxkQ4cyex6hM6RYTRUSr7jVD9K4d8KFP2g85i69YLtSu01W1Np0afpJ4a9
MK0E7ISMNRmC8wIklCAsSXiBRqyaEwaSy/clybI0vCTPqGOYh3/SZg==
</SignatureValue>
<KeyInfo>
<KeyValue>
<RSAKeyValue>
<Modulus>
z8adrX9m0S8OxIxN+fui33wiz4ZYgb4xPbR9MS5pOp1A8kVpH5Ew3N6O3/dMs2a4diIxyGLV
h0r86QXWH/W6T2IC2ny+hi+jWRwXrvgTY3ZAFgePvz2OdRhVN/cUbOto4Pa4I2mVZWW+/Q0F
n7YpqPBDDxlGq/xyFPuYq/4y7Y+Ah+vHO2ZSaiQjbj8F38XrGhwlcbFVyK8AmxK3z0zWwX86
uMEqVCjW6s6j2KAWdbAjEpgZHlJY87i/DqnFgxfmdg3oru+YeiEPVRY8hyQpYbtgryveZOHT
gnCHmS/53U9jSS0cyb/ADuj1upfyNoOiMMgQr7Olhc5pTvuWAl4Fnw==</Modulus>
<Exponent>AQAB</Exponent>
</RSAKeyValue>
</KeyValue>
</KeyInfo>
</Signature>
</iodef-rid:Signature>
<!-- End of detached XML signature included in RID -->
</iodef-rid:ReportSchema>
</iodef-rid:RIDPolicy>
</iodef-rid:RID>
7.1.2. Acknowledgement Message Example
The example Acknowledgement message is in response to the Request
message listed above. The SP that received the request is responding
to approve the trace continuance in their network.
<iodef-rid:RID lang="en"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
<iodef-rid:RIDPolicy MsgType="Acknowledgement"
MsgDestination="RIDSystem">
<iodef-rid:PolicyRegion region="IntraConsortium"/>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.67</iodef:Address>
</iodef:Node>
<iodef-rid:TrafficType type="Attack"/>
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#207-1
</iodef:IncidentID>
</iodef-rid:RIDPolicy>
<iodef-rid:RequestStatus AuthorizationStatus="Approved"/>
</iodef-rid:RID>
7.1.3. Result Message Example
The example Result message is in response to the Request listed
above. This message type only comes after an Acknowledgement within
the Request flow of messages where a TraceRequest is in progress. It
may be a direct response to a Request with the MsgType set to
'InvestigationRequest'. This message provides information about the
source of the attack and the actions taken to mitigate the traffic.
The Result message is typically the last message in a Request flow;
however, an Acknowledgement MAY follow if there are any issues
receiving or processing the Result.
<iodef-rid:RID lang="en"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
<iodef-rid:RIDPolicy MsgType="Result"
MsgDestination="RIDSystem">
<iodef-rid:PolicyRegion region="IntraConsortium"/>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.67</iodef:Address>
</iodef:Node>
<iodef-rid:TrafficType type="Attack"/>
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#207-1
</iodef:IncidentID>
<!-- IODEF-Document included in RID -->
<iodef-rid:ReportSchema Version="1.0">
<iodef-rid:XMLDocument dtype="xml" meaning="xml">
<iodef:IODEF-Document lang="en">
<iodef:Incident restriction="need-to-know" purpose="traceback">
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#207-1
</iodef:IncidentID>
<iodef:DetectTime>2004-02-02T22:49:24+00:00</iodef:DetectTime>
<iodef:StartTime>2004-02-02T22:19:24+00:00</iodef:StartTime>
<iodef:ReportTime>2004-02-02T23:20:24+00:00</iodef:ReportTime>
<iodef:Description>Host involved in DoS attack</iodef:Description>
<iodef:Assessment>
<iodef:Impact severity="low" completion="failed"
type="dos"/>
</iodef:Assessment>
<iodef:Contact role="creator" type="organization">
<iodef:ContactName>Constituency-contact for 192.0.2.35
</iodef:ContactName>
<iodef:Email>Constituency-contact@192.0.2.35</iodef:Email>
</iodef:Contact>
<iodef:EventData>
<iodef:Contact role="admin" type="organization">
<iodef:ContactName>Admin-contact for 192.0.2.35
</iodef:ContactName>
<iodef:Email>Admin-contact@10.1.1.2</iodef:Email>
</iodef:Contact>
<iodef:Flow>
<iodef:System category="intermediate">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.35
</iodef:Address>
</iodef:Node>
</iodef:System>
</iodef:Flow>
<iodef:EventData>
<iodef:Contact role="admin" type="organization">
<iodef:ContactName>Admin-contact for 192.0.2.3
</iodef:ContactName>
<iodef:Email>Admin-contact@192.0.2.3</iodef:Email>
</iodef:Contact>
<iodef:Flow>
<iodef:System category="intermediate">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.3
</iodef:Address>
</iodef:Node>
</iodef:System>
</iodef:Flow>
</iodef:EventData>
</iodef:EventData>
<iodef:EventData>
<iodef:Flow>
<iodef:System category="source">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.35
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>38765</iodef:Port>
</iodef:Service>
</iodef:System>
<iodef:System category="target">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.67
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>80</iodef:Port>
</iodef:Service>
</iodef:System>
</iodef:Flow>
<iodef:Expectation severity="high" action="rate-limit-host">
<iodef:Description>
Rate-limit traffic close to source
</iodef:Description>
</iodef:Expectation>
<iodef:Record>
<iodef:RecordData>
<iodef:Description>
The IPv4 packet included was used in the described attack
</iodef:Description>
<iodef:RecordItem dtype="ipv4-packet">450000522ad9
0000ff06c41fc0a801020a010102976d0050103e020810d9
4a1350021000ad6700005468616e6b20796f7520666f7220
6361726566756c6c792072656164696e6720746869732052
46432e0a
</iodef:RecordItem>
</iodef:RecordData>
</iodef:Record>
</iodef:EventData>
<iodef:History>
<iodef:HistoryItem action="rate-limit-host">
<iodef:DateTime>2004-02-02T22:53:01+00:00</iodef:DateTime>
<iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
CSIRT-FOR-OUR-DOMAIN#207-1
</iodef:IncidentID>
<iodef:Description>
Notification sent to next upstream SP closer to 192.0.2.35
</iodef:Description>
</iodef:HistoryItem>
<iodef:HistoryItem action="rate-limit-host">
<iodef:DateTime>2004-02-02T23:07:21+00:00</iodef:DateTime>
<iodef:IncidentID name="CSIRT-FOR-SP3">
CSIRT-FOR-SP3#3291-1
</iodef:IncidentID>
<iodef:Description>
Host rate-limited for 24 hours
</iodef:Description>
</iodef:HistoryItem>
</iodef:History>
</iodef:Incident>
</iodef:IODEF-Document>
</iodef-rid:XMLDocument>
<!-- End of IODEF-Document included in RID -->
</iodef-rid:ReportSchema>
</iodef-rid:RIDPolicy>
<iodef-rid:IncidentSource>
<iodef-rid:SourceFound>true</iodef-rid:SourceFound>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.37</iodef:Address>
</iodef:Node>
</iodef-rid:IncidentSource>
</iodef-rid:RID>
7.2. Investigation Request Communication Flow
The diagram below outlines a RID Request communication flow between
RID systems on different networks for a security incident with a
known source address. Therefore, MsgDestination is set to
'InvestigationRequest' for the Request message and is included in the
diagram below as "Investigation". The proper response to a Request
with the MsgDestination set to 'InvestigationRequest' is a Result
message. If there is a problem with the Request, such as a failure
to validate the digital signature or decrypt the Request, an
Acknowledgement message is sent to the requestor. The
Acknowledgement message should provide the reason why the message
could not be processed.
Attack Dest SP-1 SP-2 Attack Src
1. Attack | Attack
reported | detected
2. Determine source
of security incident
3. o---Investigation---->
4. Research
incident and
determine appropriate
actions to take
5. <-------Result-------o
Figure 9: Investigation Request Communication Flow
7.2.1. Investigation Request Example
The following example only includes the RID-specific details. The
IODEF and security measures are similar to the TraceRequest, with the
exception that the source is known, the receiving RID system is known
to be close to the source, and the MsgDestination is set to
'InvestigationRequest'. The source known is indicated in the IODEF
document, which allows for incident sources to be listed as spoofed,
if appropriate.
This flow does not include a Result message because the request is
denied as shown in the Acknowledgement response.
SP-1 is represented by CERT-FOR-OUR-DOMAIN and 192.0.2.67. SP-2 is
identified by 192,0.2.98. In this example, SP-2 is the service
provider for systems on the 192.0.2.32/27 subnet. The contact for
the host 192.0.2.35 is known at the start of the request as
'Constituency-contact@10.1.1.2'.
<iodef-rid:RID lang="en"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
<iodef-rid:RIDPolicy MsgType="InvestigationRequest"
MsgDestination="SourceOfIncident">
<iodef-rid:PolicyRegion region="PeerToPeer"/>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.98</iodef:Address>
</iodef:Node>
<iodef-rid:TrafficType type="Attack"/>
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#208-1
</iodef:IncidentID>
<!-- IODEF-Document included in RID -->
<iodef-rid:ReportSchema Version="1.0">
<iodef-rid:XMLDocument dtype="xml" meaning="xml">
<iodef:IODEF-Document lang="en">
<iodef:Incident restriction="need-to-know" purpose="other">
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#208-1
</iodef:IncidentID>
<iodef:DetectTime>2004-02-05T08:13:33+00:00</iodef:DetectTime>
<iodef:StartTime>2004-02-05T08:13:31+00:00</iodef:StartTime>
<iodef:EndTime>2004-02-05T08:13:33+00:00</iodef:EndTime>
<iodef:ReportTime>2004-02-05T08:13:35+00:00</iodef:ReportTime>
<iodef:Description>Host involved in DoS attack</iodef:Description>
<iodef:Assessment>
<iodef:Impact severity="low" completion="failed" type="recon"/>
</iodef:Assessment>
<iodef:Contact role="creator" type="organization">
<iodef:ContactName>Constituency-contact for 192.0.2.35
</iodef:ContactName>
<iodef:Email>Constituency-contact@10.1.1.2</iodef:Email>
</iodef:Contact>
<iodef:EventData>
<iodef:Flow>
<iodef:System category="source">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.35
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>41421</iodef:Port>
</iodef:Service>
</iodef:System>
<iodef:System category="target">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.67
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>80</iodef:Port>
</iodef:Service>
</iodef:System>
</iodef:Flow>
<iodef:Expectation severity="high" action="investigate">
<iodef:Description>
Investigate whether source has been compromised
</iodef:Description>
</iodef:Expectation>
</iodef:EventData>
<iodef:History>
<iodef:HistoryItem action="block-host">
<iodef:DateTime>2004-02-05T08:19:01+00:00</iodef:DateTime>
<iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
CSIRT-FOR-OUR-DOMAIN#208-1
</iodef:IncidentID>
<iodef:Description>
Investigation request sent to SP for 192.0.2.35
</iodef:Description>
</iodef:HistoryItem>
</iodef:History>
</iodef:Incident>
</iodef:IODEF-Document>
</iodef-rid:XMLDocument>
<!-- End of IODEF-Document included in RID -->
</iodef-rid:ReportSchema>
</iodef-rid:RIDPolicy>
</iodef-rid:RID>
7.2.2. Acknowledgement Message Example
The example Acknowledgement message is in response to the Request
listed above. The SP that received the request was unable to
validate the digital signature used to authenticate the sending RID
system.
<iodef-rid:RID lang="en"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
<iodef-rid:RIDPolicy MsgType="Acknowledgement"
MsgDestination="RIDSystem">
<iodef-rid:PolicyRegion region="IntraConsortium"/>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.67</iodef:Address>
</iodef:Node>
<iodef-rid:TrafficType type="Attack"/>
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#208-1
</iodef:IncidentID>
</iodef-rid:RIDPolicy>
<iodef-rid:RequestStatus AuthorizationStatus="Denied"
Justification="Authentication"/>
</iodef-rid:RID>
7.3. Report Communication Flow
The diagram below outlines the RID Report communication flow between
RID systems on different SPs.
SP-1 SP-2
1. Generate incident information
and prepare Report message
2. o-------Report------->
3. File report in database
Figure 10: Report Communication Flow
The Report communication flow is used to provide information on
incidents. Incident information may be shared between CSIRTs or
other entities using this format. When a report is received, the RID
system must verify that the report has not already been filed. The
incident number and incident data, such as the hexadecimal packet and
incident class information, can be used to compare with existing
database entries. The Report message typically does not have a
response. If there is a problem with the Report message, such as a
failure to validate the digital signature [RFC3275] or decrypt the
request, an Acknowledgement message is sent to the requestor. The
Acknowledgement message should provide the reason why the message
could not be processed.
7.3.1. Report Example
The following example only includes the RID-specific details. This
report is an unsolicited Report message that includes an IPv4 packet.
The IODEF document and digital signature is similar to the Request
example with MsgDestination set to 'TraceRequest'.
This example is a message sent from SP-1, CERT-FOR-OUR-DOMAIN at
192.0.2.67, to SP-2 at 192.0.2.130 for informational purposes on an
attack that took place.
<iodef-rid:RID lang="en"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
<iodef-rid:RIDPolicy MsgType="Report" MsgDestination="RIDSystem">
<iodef-rid:PolicyRegion region="PeerToPeer"/>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.130</iodef:Address>
</iodef:Node>
<iodef-rid:TrafficType type="Attack"/>
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#209-1
</iodef:IncidentID>
<!-- IODEF-Document included in RID -->
<iodef-rid:ReportSchema>
<iodef-rid:XMLDocument dtype="xml" meaning="xml">
<iodef:IODEF-Document lang="en">
<iodef:Incident restriction="need-to-know" purpose="reporting">
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#209-1
</iodef:IncidentID>
<iodef:DetectTime>2004-02-05T10:21:08+00:00</iodef:DetectTime>
<iodef:StartTime>2004-02-05T10:21:05+00:00</iodef:StartTime>
<iodef:EndTime>2004-02-05T10:35:00+00:00</iodef:EndTime>
<iodef:ReportTime>2004-02-05T10:27:38+00:00</iodef:ReportTime>
<iodef:Description>Host illicitly accessed admin account
</iodef:Description>
<iodef:Assessment>
<iodef:Impact severity="high" completion="succeeded"
type="admin"/>
<iodef:Confidence rating="high"/>
</iodef:Assessment>
<iodef:Contact role="creator" type="organization">
<iodef:ContactName>Constituency-contact for 192.0.2.35
</iodef:ContactName>
<iodef:Email>Constituency-contact@10.1.1.2</iodef:Email>
</iodef:Contact>
<iodef:EventData>
<iodef:Flow>
<iodef:System category="source">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.35
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>32821</iodef:Port>
</iodef:Service>
</iodef:System>
<iodef:System category="target">
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.67
</iodef:Address>
</iodef:Node>
<iodef:Service ip_protocol="6">
<iodef:Port>22</iodef:Port>
</iodef:Service>
</iodef:System>
</iodef:Flow>
</iodef:EventData>
<iodef:History>
<iodef:HistoryItem action="rate-limit-host">
<iodef:DateTime>2004-02-05T10:28:00+00:00</iodef:DateTime>
<iodef:IncidentID name="CSIRT-FOR-OUR-DOMAIN">
CSIRT-FOR-OUR-DOMAIN#209-1
</iodef:IncidentID>
<iodef:Description>
Incident report sent to SP for 192.0.2.35
</iodef:Description>
</iodef:HistoryItem>
</iodef:History>
</iodef:Incident>
</iodef:IODEF-Document>
</iodef-rid:XMLDocument>
<!-- End of IODEF-Document included in RID -->
</iodef-rid:ReportSchema>
</iodef-rid:RIDPolicy>
</iodef-rid:RID>
7.4. Query Communication Flow
The diagram below outlines the RID Query communication flow between
RID systems on different networks.
SP-1 SP-2
1. Generate a request for
information on a specific
incident number or incident type
2. o-------Query------->
3. Verify policy information
and determine if matches exist
for requested information
4. <-------Report------o
5. Associate report to request
by incident number or type
and file report(s).
Figure 11: Query Communication Flow
The Query message communication receives a response of a Report
message. If the Report message is empty, the responding host did not
have information available to share with the requestor. The incident
number and responding RID system, as well as the transport, assist in
the association of the request and response since a report can be
filed and is not always solicited. If there is a problem with the
Query message, such as a failure to validate the digital signature or
decrypt the request, an Acknowledgement message is sent to the
requestor. The Acknowledgement message should provide the reason why
the message could not be processed.
7.4.1. Query Example
The Query request may be received in several formats as a result of
the type of query being performed. If the incident number is the
only information provided, the IODEF document and IP packet data may
not be needed to complete the request. However, if a type of
incident is requested, the incident number remains NULL, and the IP
packet data will not be included in the IODEF RecordItem class; the
other incident information is the main source for comparison. In the
case in which an incident number may not be the same between CSIRTs,
the incident number and/or IP packet information can be provided and
used for comparison on the receiving RID system to generate (a)
Report message(s).
This query is sent to 192.0.2.3, inquiring about the incident with
the identifier CERT-FOR-OUR-DOMAIN#210-1. The Report will be
provided to the requestor identified and verified through the
authentication and digital signature information provided in the RID
message. An example Report is provided above.
<iodef-rid:RID lang="en"
xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0">
<iodef-rid:RIDPolicy MsgType="Query"
MsgDestination="RIDSystem">
<iodef-rid:PolicyRegion region="PeerToPeer"/>
<iodef:Node>
<iodef:Address category="ipv4-addr">192.0.2.3</iodef:Address>
</iodef:Node>
<iodef-rid:TrafficType type="Attack"/>
<iodef:IncidentID name="CERT-FOR-OUR-DOMAIN">
CERT-FOR-OUR-DOMAIN#210-1
</iodef:IncidentID>
</iodef-rid:RIDPolicy>
</iodef-rid:RID>
8. RID Schema Definition
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-2.0"
xmlns:iodef="urn:ietf:params:xml:ns:iodef-1.0"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
targetNamespace="urn:ietf:params:xml:ns:iodef-rid-2.0"
elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:import namespace="urn:ietf:params:xml:ns:iodef-1.0"
schemaLocation="http://www.iana.org/assignments/xml-registry/schema/
iodef-1.0.xsd"/>
<xs:import namespace="http://www.w3.org/2000/09/xmldsig#"
schemaLocation="http://www.w3.org/TR/xmldsig-core/
xmldsig-core-schema.xsd"/>
<!-- ****************************************************************
*********************************************************************
*** Real-time Inter-network Defense - RID XML Schema ***
*** Namespace - iodef-rid, April 2012 ***
*** The namespace is defined to support transport of IODEF ***
*** documents for exchanging incident information. ***
*********************************************************************
-->
<!--RID messages act as an envelope for IODEF and RID documents
to support the exchange of incident information-->
<!--
====== Real-Time Inter-network Defense - RID ======
==== Suggested definition for RID messaging ======
-->
<xs:annotation>
<xs:documentation>XML Schema wrapper for IODEF</xs:documentation>
</xs:annotation>
<xs:element name="RID" type="iodef-rid:RIDType"/>
<xs:complexType name="RIDType">
<xs:sequence>
<xs:element ref="iodef-rid:RIDPolicy" minOccurs="0"/>
<xs:element ref="iodef-rid:RequestStatus" minOccurs="0"/>
<xs:element ref="iodef-rid:IncidentSource" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="lang"
type="xs:language" use="required"/>
</xs:complexType>
<!--Used in Acknowledgement Message for RID-->
<xs:element name="RequestStatus" type="iodef-rid:RequestStatusType"/>
<xs:complexType name="RequestStatusType">
<xs:attribute name="AuthorizationStatus" use="required">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="Approved"/>
<xs:enumeration value="Denied"/>
<xs:enumeration value="Pending"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-AuthorizationStatus"
type="xs:string" use="optional"/>
<xs:attribute name="Justification">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="SystemResource"/>
<xs:enumeration value="Authentication"/>
<xs:enumeration value="AuthenticationOrigin"/>
<xs:enumeration value="Encryption"/>
<xs:enumeration value="UnrecognizedFormat"/>
<xs:enumeration value="CannotProcess"/>
<xs:enumeration value="Other"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-Justification"
type="xs:string" use="optional"/>
<xs:attribute name="restriction" type="iodef:restriction-type"/>
</xs:complexType>
<!--Incident Source Information for Result Message-->
<xs:element name="IncidentSource" type="iodef-rid:IncidentSourceType"/>
<xs:complexType name="IncidentSourceType">
<xs:sequence>
<xs:element ref="iodef-rid:SourceFound"/>
<xs:element ref="iodef:Node" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="restriction" type="iodef:restriction-type"/>
</xs:complexType>
<xs:element name="SourceFound" type="xs:boolean"/>
<!--
====== Real-Time Inter-network Defense Policy - RIDPolicy ======
====== Definition for RIDPolicy for messaging
-->
<xs:annotation>
<xs:documentation>RID Policy used for transport of
messages</xs:documentation>
</xs:annotation>
<!-- RIDPolicy information with setting information listed in RID
documentation -->
<xs:element name="RIDPolicy" type="iodef-rid:RIDPolicyType"/>
<xs:complexType name="RIDPolicyType">
<xs:sequence>
<xs:element ref="iodef-rid:PolicyRegion" maxOccurs="unbounded"/>
<xs:element ref="iodef:Node"/>
<xs:element ref="iodef-rid:TrafficType" maxOccurs="unbounded"/>
<xs:element ref="iodef:IncidentID" minOccurs="0"/>
<xs:element ref="iodef-rid:ReportSchema" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="MsgType" use="required">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="TraceRequest"/>
<xs:enumeration value="Acknowledgement"/>
<xs:enumeration value="Result"/>
<xs:enumeration value="InvestigationRequest"/>
<xs:enumeration value="Report"/>
<xs:enumeration value="Query"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-MsgType" type="xs:string" use="optional"/>
<xs:attribute name="MsgDestination" use="required">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="RIDSystem"/>
<xs:enumeration value="SourceOfIncident"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-MsgDestination" type="xs:string"
use="optional"/>
<xs:attribute name="restriction" type="iodef:restriction-type"/>
</xs:complexType>
<xs:element name="PolicyRegion">
<xs:complexType>
<xs:attribute name="region" use="required">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="ClientToSP"/>
<xs:enumeration value="SPToClient"/>
<xs:enumeration value="IntraConsortium"/>
<xs:enumeration value="PeerToPeer"/>
<xs:enumeration value="BetweenConsortiums"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-region"
type="xs:string" use="optional"/>
</xs:complexType>
</xs:element>
<xs:element name="TrafficType">
<xs:complexType>
<xs:attribute name="type" use="required">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="Attack"/>
<xs:enumeration value="Network"/>
<xs:enumeration value="Content"/>
<xs:enumeration value="DataWithHandlingRequirements"/>
<xs:enumeration value="AudienceRestriction"/>
<xs:enumeration value="Other"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-type"
type="xs:string" use="optional"/>
</xs:complexType>
</xs:element>
<!--Used to include an enveloped XML document in RID-->
<xs:element name="ReportSchema" type="iodef-rid:ReportSchemaType"/>
<xs:complexType name="ReportSchemaType">
<xs:sequence>
<xs:element ref="iodef-rid:XMLDocument" minOccurs="1"
maxOccurs="1"/>
<xs:element ref="iodef-rid:URL" minOccurs="0"
maxOccurs="1"/>
<xs:element ref="iodef-rid:Signature" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="Version" use="optional">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="1.0"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-Version"
type="xs:string" use="optional"/>
<xs:attribute name="XMLSchemaID" use="optional">
<xs:simpleType>
<xs:restriction base="xs:anyURI">
<xs:whiteSpace value="collapse"/>
<xs:enumeration value="urn:ietf:params:xml:ns:iodef-1.0"/>
<xs:enumeration value="ext-value"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="ext-XMLSchemaID"
type="xs:string" use="optional"/>
</xs:complexType>
<xs:element name="XMLDocument"
type="iodef:ExtensionType"/>
<xs:element name="URL"
type="xs:anyURI"/>
<xs:element name="Signature"
type="iodef:ExtensionType"/>
</xs:schema>
9. Security Requirements
9.1. XML Digital Signatures and Encryption
RID leverages existing security standards and data markings in
RIDPolicy to achieve the required levels of security for the exchange
of incident information. The use of standards includes TLS and the
XML security features of encryption [XMLencrypt] and digital
signatures [RFC3275] [XMLsig]. The standards provide clear methods
to ensure that messages are secure, authenticated, and authorized;
meet policy and privacy guidelines; and maintain integrity. XML
Signature Best Practices [XMLSigBP] should be referenced by
implementers for information on improving security to mitigate
attacks.
As specified in the relevant sections of this document, the XML
digital signature [RFC3275] and XML encryption [XMLencrypt] are used
in the following cases:
XML Digital Signature
o The originator of a Request MUST use a detached signature to sign
at least one of the original elements contained in the RecordItem
class to provide authentication to all upstream participants in
the trace or those involved in the investigation. All instances
of RecordItem provided by the originator may be individually
signed, and additional RecordItem entries by upstream peers in the
trace or investigation may be signed by the peer adding the data,
while maintaining the original RecordItem entry(s) and detached
signature(s) from the original requestor. It is important to note
that the data is signed at the RecordItem level. Since multiple
RecordItems may exist within an IODEF document and may originate
from different sources, the signature is applied at the RecordItem
level to enable the use of an XML detached signature. Exclusive
canonicalization [XMLCanon] is REQUIRED for the detached signature
and not the references, as the XML document generated is then
included in the RID message within the Signature element of the
ReportSchema class. This signature MUST be passed to all
recipients of the Request message.
o If a Request does not include a RecordItem entry, a timestamp MUST
be used to ensure there is data to be signed for the multi-hop
authentication use case. The DateTime element of the iodef:
RecordData class ([RFC5070], Section 3.19.1) is used for this
purpose.
o For all message types, the full IODEF-RID document MUST be signed
using an enveloped signature by the sending peer to provide
authentication and integrity to the receiving RID system. The
signature is placed in an instance of the Signature element.
o XML Signature Best Practices [XMLSigBP] guidance SHOULD be
followed to prevent or mitigate security risks. Examples include
the recommendation to authenticate a signature prior to processing
(executing potentially dangerous operations) and the
recommendation to limit the use of URIs since they may enable
cross-site scripting attacks or access to local information.
o XML Path Language (XPath) 2.0 [XMLPath] MUST be followed to
specify the portion of the XML document to be signed. XPath is
used to specify a location within an XML document. Best practice
recommendations for using XPath [XMLSigBP] SHOULD be referenced to
reduce the risk of denial-of-service attacks. The use of XSLT
transforms MUST be restricted according to security guidance in
[XMLSigBP].
XML Encryption
o The IODEF-RID document MAY be encrypted to provide an extra layer
of security between peers so that not only the message is
encrypted for transport. This behavior would be agreed upon
between peers or a consortium, or determined on a per-message
basis, depending on security requirements. It should be noted
that there are cases for transport where the RIDPolicy class needs
to be presented in clear text, as detailed in the transport
document [RFC6546].
o A Request, or any other message type that may be relayed through
RID systems before reaching the intended destination as a result
of trust relationships, MAY be encrypted specifically for the
intended recipient. This may be necessary if the RID network is
being used for message transfer, the intermediate parties do not
need to have knowledge of the request contents, and a direct
communication path does not exist. In that case, the RIDPolicy
class is used by intermediate parties and as such, RIDPolicy is
maintained in clear text.
o The action taken in the Result message may be encrypted using the
key of the request originator. In that case, the intermediate
parties can view the RIDPolicy information and know the trace has
been completed and do not need to see the action. If the use of
encryption were limited to sections of the message, the History
class information would be encrypted. Otherwise, it is
RECOMMENDED to encrypt the entire IODEF-RID document and use an
enveloped signature for the originator of the request. The
existence of the Result message for an incident would tell any
intermediate parties used in the path of the incident
investigation that the incident handling has been completed.
o The iodef:restriction attribute sets expectations for the privacy
of an incident and is defined in Section 3.2 of RFC 5070.
Following the guidance for XML encryption in the Security
Requirements section, the iodef:restriction attribute can be set
in any of the RID classes to define restrictions and encryption
requirements for the exchange of incident information. The
restriction options enable encryption capabilities for the
complete exchange of an IODEF document (including any extensions),
within specific classes of IODEF, or IODEF extensions, where more
limited restrictions are desired. The restriction attribute is
contained in each of the RID classes and MUST be used in
accordance with confidentiality expectations for either sections
of the IODEF document or the complete IODEF document. Consortiums
and organizations should consider this guidance when creating
exchange policies.
o Expectations based on how restriction is set:
* If restriction is set to 'private', the class or document MUST
be encrypted for the recipient using XML encryption and the
public key of the recipient. See Section 9.3 for a discussion
on public key infrastructure (PKI) and other security
requirements.
* If restriction is set to 'need-to-know', the class or document
MUST be encrypted to ensure only those with need-to-know access
can decrypt the data. The document can either be encrypted for
each individual for which access is intended or be encrypted
with a single group key. The method used SHOULD adhere to any
certificate policy and practices agreements between entities
for the use of RID. A group key in this instance refers to a
single key (symmetric) that is used to encrypt the block of
data. The users with need-to-know access privileges may be
given access to the shared key via a secure distribution
method, for example, providing access to the symmetric key
encrypted with each of the user's public keys.
* If restriction is set to 'public', the class or document MUST
be sent in clear text. This setting can be critical if certain
sections of a document or an entire document are to be shared
without restrictions. This provides flexibility within an
incident to share certain information freely where appropriate.
* If restriction is set to 'default', the information can be
shared according to an information disclosure policy pre-
arranged by the communicating parties.
o Expectations based on placement of the restriction setting:
* If restriction is set within one of the RID classes, the
restriction applies to the entire IODEF document.
* If restriction is set within individual IODEF classes, the
restriction applies to the specific IODEF class and the
children of that class.
The formation of policies is a very important aspect of using a
messaging system like RID to exchange potentially sensitive
information. Many considerations should be involved for peering
parties, and some guidelines to protect the data, systems, and
transport are covered in this section. Policies established should
provide guidelines for communication methods, security, and fall-back
procedures. See Sections 9.4 and 9.5 for additional information on
consortiums and PKI considerations.
The security considerations for the storage and exchange of
information in RID messaging may include adherence to local,
regional, or national regulations in addition to the obligations to
protect client information during an investigation. RIDPolicy is a
necessary tool for listing the requirements of messages to provide a
method to categorize data elements for proper handling. Controls are
also provided for the sending entity to protect messages from third
parties through XML encryption.
RID provides a method to exchange incident-handling requests and
Report messages between entities. Administrators have the ability to
base decisions on the available resources and other factors of their
network and maintain control of incident investigations within their
own network. Thus, RID provides the ability for participating
networks to manage their own security controls, leveraging the
information listed in RIDPolicy.
RID is used to transfer or exchange XML documents in an IODEF format
or using another IANA-registered format. Implementations SHOULD NOT
download schemas at runtime due to the security implications, and
included documents MUST NOT be required to provide a resolvable
location of their schema.
9.2. Message Transport
A transport specification is defined in a separate document
[RFC6546]. The specified transport protocols MUST use encryption to
provide an additional level of security and integrity, while
supporting mutual authentication through bidirectional certificate
usage. Any subsequent transport method defined should take advantage
of existing standards for ease of implementation and integration of
RID systems. Session encryption for the transport of RID messages is
enforced in the transport specification. The privacy and security
considerations are addressed fully in RID to protect sensitive
portions of documents and to provide a method to authenticate the
messages. Therefore, RID messages do not rely on the security
provided by the transport layer alone. The encryption requirements
and considerations for RID messages are discussed in Section 9.1 of
this document.
Consortiums may vary their selected transport mechanisms and thus
decide upon a mutual protocol to use for transport when communicating
with peers in a neighboring consortium using RID. RID systems MUST
implement and deploy HTTPS as defined in the transport document
[RFC6546] and optionally MAY support other protocols such as the
Blocks Extensible Exchange Protocol (BEEP) [RFC3080]. Bindings would
need to be defined to enable support for other transport protocols.
Systems used to send authenticated RID messages between networks MUST
use a secured system and interface to connect to a border network's
RID systems. Each connection to a RID system MUST meet the security
requirements agreed upon through the consortium regulations, peering,
or SLAs. The RID system MUST listen for and send RID messages on
only the designated port, which also MUST be over an encrypted tunnel
meeting the minimum requirement of algorithms and key lengths
established by the consortium, peering, or SLA. The selected
cryptographic algorithms for symmetric encryption, digital
signatures, and hash functions MUST meet minimum security levels of
the times. The encryption strength MUST adhere to import and export
regulations of the involved countries for data exchange.
Out-of-band communications dedicated to SP interaction for RID
messaging would provide additional security as well as guaranteed
bandwidth during a denial-of-service attack. For example, an out-of-
band channel may consist of logical paths defined over the existing
network. Out-of-band communications may not be practical or possible
between service providers, but provisions should be considered to
protect the incident management systems used for RID messaging.
Methods to protect the data transport may also be provided through
session encryption.
9.3. Public Key Infrastructure
It is RECOMMENDED that RID, the XML security functions, and transport
protocols properly integrate with a PKI managed by the consortium,
federate PKIs within a consortium, or use a PKI managed by a trusted
third party. Entities MAY use shared keys as an alternate solution,
although this may limit the ability to validate certificates and
could introduce risk. For the Internet, a few examples of existing
efforts that could be leveraged to provide the supporting PKI include
the Regional Internet Registry's (RIR's) PKI hierarchy, vendor issued
certificates, or approved issuers of Extended Validation (EV)
Certificates. Security and privacy considerations related to
consortiums are discussed in Sections 9.4 and 9.5.
The use of PKI between entities or by a consortium SHOULD adhere to
any applicable certificate policy and practices agreements for the
use of RID. [RFC3647] specifies a commonly used format for
certificate policy (CP) and certification practices statements (CPS).
Systems with predefined relationships for RID include those who peer
directly or through a consortium with agreed-upon appropriate use
agreements. The agreements to trust other entities may be based on
assurance levels that could be determined by a comparison of the CP,
CPS, and/or RID operating procedures. The initial comparison of
policies and the ability to audit controls provide a baseline
assurance level for entities to form and maintain trust
relationships. Trust relationships may also be defined through a
bridged or hierarchical PKI in which both peers belong. If shared
keys or keys issued from a common CA are used, the verification of
controls to determine the assurance level to trust other entities may
be limited to the RID policies and operating procedures.
XML security functions utilized in RID require a trust center such as
a PKI for the distribution of credentials to provide the necessary
level of security for this protocol. Layered transport protocols
also utilize encryption and rely on a trust center. Public key
certificate pairs issued by a trusted Certification Authority (CA)
MAY be used to provide the necessary level of authentication and
encryption for the RID protocol. The CA used for RID messaging must
be trusted by all involved parties and may take advantage of similar
efforts, such as the Internet2 federated PKI or the ARIN/RIR effort
to provide a PKI to service providers. The PKI used for
authentication also provides the necessary certificates needed for
encryption used for the RID transport protocol [RFC6546].
9.3.1. Authentication
Hosts receiving a RID message MUST be able to verify that the sender
of the request is valid and trusted. Using digital signatures on a
hash of the RID message with an X.509 version 3 certificate issued by
a trusted party MUST be used to authenticate the request. The X.509
version 3 specifications as well as the digital signature
specifications and path validation standards set forth in [RFC5280]
MUST be followed in order to interoperate with a PKI designed for
similar purposes. Full path validation verifies the chaining
relationship to a trusted root and also performs a certificate
revocation check. The use of digital signatures in RID XML messages
MUST follow the World Wide Web Consortium (W3C) recommendations for
signature syntax and processing when either the XML encryption
[XMLencrypt] or digital signature [XMLsig] [RFC3275] is used within a
document.
It might be helpful to define an extension to the authentication
scheme that uses attribute certificates [RFC5755] in such a way that
an application could automatically determine whether human
intervention is needed to authorize a request; however, the
specification of such an extension is out of scope for this document.
The use of pre-shared keys may be considered for authentication at
the transport layer. If this option is selected, the specifications
set forth in "Pre-Shared Key Ciphersuites for Transport Layer
Security (TLS)" [RFC4279] MUST be followed. Transport specifications
are detailed in a separate document [RFC6546].
9.3.2. Multi-Hop Request Authentication
The use of multi-hop authentication in a Request is used when a
Request is sent to multiple entities or SPs in an iterative manner.
Multi-hop authentication is REQUIRED in Requests that involve
multiple SPs where Requests are forwarded iteratively through peers.
Bilateral trust relationships MAY be used between peers; multi-hop
authentication MUST be used for cases where the originator of a
message is authenticated several hops into the message flow.
For practical reasons, SPs may want to prioritize incident-handling
events based upon the immediate peer for a Request, the originator of
a request, and the listed Confidence rating for the incident. In
order to provide a higher assurance level of the authenticity of a
Request, the originating RID system is included in the Request along
with contact information and the information of all RID systems in
the path the trace has taken. This information is provided through
the IODEF EventData class, which nests the list of systems and
contacts involved in a trace, while setting the category attribute to
"infrastructure".
To provide multi-hop authentication, the originating RID system MUST
include a digital signature in the Request sent to all systems in the
upstream path. The digital signature from the RID system is
performed on the RecordItem class of the IODEF following the XML
digital signature specifications from W3C [XMLsig] using a detached
signature. The signature MUST be passed to all parties that receive
a Request, and each party MUST be able to perform full path
validation on the digital signature [RFC5280]. In order to
accommodate that requirement, the RecordItem data MUST remain
unchanged as a request is passed along between providers and is the
only element for which the signature is applied. If additional
RecordItems are included in the document at upstream peers, the
initial RecordItem entry MUST still remain with the detached
signature. The subsequent RecordItem elements may be signed by the
peer adding the incident information for the investigation. A second
benefit to this requirement is that the integrity of the filter used
is ensured as it is passed to subsequent SPs in the upstream trace of
the incident. The trusted PKI also provides the keys used to
digitally sign the RecordItem class for a Request to meet the
requirement of authenticating the original request. Any host in the
path of the trace should be able to verify the digital signature
using the trusted PKI.
In the case in which an enterprise using RID sends a Request to its
provider, the signature from the enterprise MUST be included in the
initial request. The SP may generate a new request to send upstream
to members of the SP consortium to continue the investigation. If
the original request is sent, the originating SP, acting on behalf of
the enterprise network under attack, MUST also digitally sign, with
an enveloped signature, the full IODEF document to assure the
authenticity of the Request. An SP that offers RID as a service may
be using its own PKI to secure RID communications between its RID
system and the attached enterprise networks. SPs participating in
the trace MUST be able to determine the authenticity of RID requests.
9.4. Consortiums and Public Key Infrastructures
Consortiums are an ideal way to establish a communication web of
trust for RID messaging. It should be noted that direct
relationships may be ideal for some communications, such as those
between a provider of incident information and a subscriber of the
incident reports. The consortium could provide centralized
resources, such as a PKI, and established guidelines and control
requirements for use of RID. The consortium may assist in
establishing trust relationships between the participating SPs to
achieve the necessary level of cooperation and experience-sharing
among the consortium entities. This may be established through PKI
certificate policy [RFC3647] reviews to determine the appropriate
trust levels between organizations or entities. The consortium may
also be used for other purposes to better facilitate communication
among SPs in a common area (Internet, region, government, education,
private networks, etc.).
Using a PKI to distribute certificates used by RID systems provides
an already established method to link trust relationships between
consortiums that peer with SPs belonging to a separate consortium.
In other words, consortiums could peer with other consortiums to
enable communication of RID messages between the participating SPs.
The PKI along with Memorandums of Agreement could be used to link
border directories to share public key information in a bridge, a
hierarchy, or a single cross-certification relationship.
Consortiums also need to establish guidelines for each participating
SP to adhere to. The RECOMMENDED guidelines include:
o Physical and logical practices to protect RID systems;
o Network- and application-layer protection for RID systems and
communications;
o Proper use guidelines for RID systems, messages, and requests; and
o A PKI, certificate policy, and certification practices statement
to provide authentication, integrity, and privacy.
The functions described for a consortium's role parallel those of a
PKI federation. The PKI federations that currently exist are
responsible for establishing security guidelines and PKI trust
models. The trust models are used to support applications to share
information using trusted methods and protocols.
A PKI can also provide the same level of security for communication
between an end entity (enterprise, educational, or government
customer network) and the SP.
9.5. Privacy Concerns and System Use Guidelines
Privacy issues raise many concerns when information-sharing is
required to achieve the goal of stopping or mitigating the effects of
a security incident. The RIDPolicy class is used to automate the
enforcement of the privacy concerns listed within this document. The
privacy and system use concerns for the system communicating RID
messages and other integrated components include the following:
Service Provider Concerns:
o Privacy of data monitored and/or stored on Intrusion Detection
Systems (IDSs) for attack detection.
o Privacy of data monitored and stored on systems used to trace
traffic across a single network.
o Privacy of incident information stored on incident management
systems participating in RID communications.
Customer Attached Networks Participating in RID with SP:
o Customer networks may include enterprise, educational, government,
or other networks attached to an SP participating in RID.
Customers should review data handling policies to understand how
data will be protected by a service provider. This information
will enable customers to decide what types of data at what
sensitivity level can be shared with service providers. This
information could be used at the application layer to establish
sharing profiles for entities and groups; see Section 9.6.
o Customers should request information on the security and privacy
considerations in place by their SP and the consortium of which
the SP is a member. Customers should understand if their data
were to be forwarded, how it might be sanitized and how it will be
protected. In advance of sharing data with their SP, customers
should also understand if limitations can be placed on how it will
be used.
o Customers should be aware that their data can and will be sent to
other SPs in order to complete a trace unless an agreement stating
otherwise is made in the service level agreements between the
customer and SP. Customers considering privacy options may limit
the use of this feature if they do not want the data forwarded.
Parties Involved in the Attack:
o Privacy of the identity of a host involved in an attack or any
indicators of compromise.
o Privacy of information such as the source and destination used for
communication purposes over the monitored or RID-connected
network(s).
o Protection of data from being viewed by intermediate parties in
the path of an Request request should be considered.
Consortium Considerations:
o System use restrictions for security incident handling within the
local region's definitions of appropriate traffic. When
participating in a consortium, appropriate use guidelines should
be agreed upon and entered into contracts.
o System use prohibiting the consortium's participating SPs from
inappropriately tracing traffic to locate sources or mitigate
traffic unlawfully within the jurisdiction or region.
Inter-Consortium Considerations:
o System use between peering consortiums should consider any
government communication regulations that apply between those two
regions, such as encryption export and import restrictions.
o System use between consortiums SHOULD NOT request traffic traces
and actions beyond the scope intended and permitted by law or
inter-consortium agreements.
o System use between consortiums should consider national boundary
issues and request limits in their appropriate system use
agreements. Appropriate use should include restrictions to
prevent the use of the protocol for limiting or restricting
traffic that is otherwise permitted within the country in which
the peering consortium resides.
The security and privacy considerations listed above are for the
consortiums, SPs, and enterprises to agree upon. The agreed-upon
policies may be facilitated through use of the RIDPolicy class and
application-layer options. Some privacy considerations are addressed
through the RID guidelines for encryption and digital signatures as
described in Section 9.1.
RID is useful in determining the true source of an incident that
traverses multiple networks or to communicate security incidents and
automate the response. The information obtained from the
investigation may determine the identity of the source host or the SP
used by the source of the traffic. It should be noted that the trace
mechanism used across a single SP may also raise privacy concerns for
the clients of the network. Methods that may raise concern include
those that involve storing packets for some length of time in order
to trace packets after the fact. Monitoring networks for intrusions
and for tracing capabilities also raises concerns for potentially
sensitive valid traffic that may be traversing the monitored network.
IDSs and single-network tracing are outside of the scope of this
document, but the concern should be noted and addressed within the
use guidelines of the network. Some IDSs and single-network trace
mechanisms attempt to properly address these issues. RID is designed
to provide the information needed by any single-network trace
mechanism. The provider's choice of a single trace mechanism depends
on resources, existing solutions, and local legislation. Privacy
concerns in regard to the single-network trace must be dealt with at
the client-to-SP level and are out of scope for RID messaging.
The identity of the true source of an attack being traced through RID
could be sensitive. The true identity listed in a Result message can
be protected through the use of encryption [XMLencrypt] enveloping
the IODEF document and RID Result information, using the public
encryption key of the originating SP. Alternatively, the action
taken may be listed without the identity being revealed to the
originating SP. The ultimate goal of the RID communication system is
to stop or mitigate attack traffic, not to ensure that the identity
of the attack traffic is known to involved parties. The SP that
identifies the source should deal directly with the involved parties
and proper authorities in order to determine the guidelines for the
release of such information, if it is regarded as sensitive. In some
situations, systems used in attacks are compromised by an unknown
source and, in turn, are used to attack other systems. In that
situation, the reputation of a business or organization may be at
stake, and the action taken may be the only additional information
reported in the Result message to the originating system. If the
security incident is a minor incident, such as a zombie system used
in part of a large-scale DDoS attack, ensuring the system is taken
off the network until it has been fixed may be sufficient. The
decision is left to the system users and consortiums to determine
appropriate data to be shared given that the goal of the
specification is to provide the appropriate technical options to
remain compliant. The textual descriptions should include details of
the incident in order to protect the reputation of the unknowing
attacker and prevent the need for additional investigation. Local,
state, or national laws may dictate the appropriate reporting action
for specific security incidents.
Privacy becomes an issue whenever sensitive data traverses a network.
For example, if an attack occurred between a specific source and
destination, then every SP in the path of the trace becomes aware
that the cyber attack occurred. In a targeted attack, it may not be
desirable that information about two nation states that are battling
a cyber war would become general knowledge to all intermediate
parties. However, it is important to allow the traces to take place
in order to halt the activity since the health of the networks in the
path could also be at stake during the attack. This provides a
second argument for allowing the Result message to only include an
action taken and not the identity of the offending host. In the case
of a Request or Report, where the originating SP is aware of the SP
that will receive the request for processing, the free-form text
areas of the document could be encrypted [XMLencrypt] using the
public key of the destination SP to ensure that no other SP in the
path can read the contents. The encryption is accomplished through
the W3C [XMLencrypt] specification for encrypting an element.
In some situations, all network traffic of a nation may be granted
through a single SP. In that situation, options must support sending
Result messages from a downstream peer of that SP. That option
provides an additional level of abstraction to hide the identity and
the SP of the identified source of the traffic. Legal action may
override this technical decision after the trace has taken place, but
that is out of the technical scope of this document.
Privacy concerns when using an Request message to request action
close to the source of valid attack traffic need to be considered.
Although the intermediate SPs may relay the request if there is no
direct trust relationship to the closest SP to the source, the
intermediate SPs do not require the ability to see the contents of
the packet or the text description field(s) in the request. This
message type does not require any action by the intermediate RID
systems, except to relay the packet to the next SP in the path.
Therefore, the contents of the request may be encrypted for the
destination system. The intermediate SPs only need to know how to
direct the request to the manager of the ASN in which the source IP
address belongs.
Traces must be legitimate security-related incidents and not used for
purposes such as sabotage or censorship. An example of such abuse of
the system includes a request to block or rate-limit legitimate
traffic to prevent information from being shared between users on the
Internet (restricting access to online versions of papers) or
restricting access from a competitor's product in order to sabotage a
business.
Intra-consortium RID communications raise additional issues,
especially when the peering consortiums reside in different regions
or nations. Request messages and requested actions to mitigate or
stop traffic must adhere to the appropriate use guidelines and yet
prevent abuse of the system. First, the peering consortiums must
identify the types of traffic that can be traced between the borders
of the participating SPs of each consortium. The traffic traced
should be limited to security-incident-related traffic. Second, the
traces permitted within one consortium, if passed to a peering
consortium, may infringe upon the peering consortium's freedom-of-
information laws. An example would be a consortium in one country
permitting a trace of traffic containing objectionable material,
outlawed within that country. The RID trace may be a valid use of
the system within the confines of that country's network border;
however, it may not be permitted to continue across network
boundaries where such content is permitted under law. By continuing
the trace in another country's network, the trace and response could
have the effect of improperly restricting access to data. A
continued trace into a second country may break the laws and
regulations of that nation. Any such traces MUST cease at the
country's border.
The privacy concerns listed in this section address issues among the
trusted parties involved in a trace within an SP, a RID consortium,
and peering RID consortiums. Data used for RID communications must
also be protected from parties that are not trusted. This protection
is provided through the authentication and encryption of documents as
they traverse the path of trusted servers and through the local
security controls in place for the incident management systems. Each
RID system MUST perform a bidirectional authentication when sending a
RID message and use the public encryption key of the upstream or
downstream peer to send a message or document over the network. This
means that the document is decrypted and re-encrypted at each RID
system via TLS over a transport protocol such as [RFC6546]. The RID
messages may be decrypted at each RID system in order to properly
process the request or relay the information. Today's processing
power is more than sufficient to handle the minimal burden of
encrypting and decrypting relatively small typical RID messages.
9.6. Sharing Profiles and Policies
The application layer can be used to establish workflows and rulesets
specific to sharing profiles for entities or consortiums. The
profiles can leverage sharing agreements to restrict data types or
classifications of data that are shared. The level of information or
classification of data shared with any entity may be based on
protection levels offered by the receiving entity and periodic
validation of those controls. The profile may also indicate how far
information can be shared according to the entity and data type. The
profile may also indicate whether requests to share data from an
entity must go directly to that entity.
In some cases, pre-defined sharing profiles will be possible. These
include any use case where an agreement is in place in advance of
sharing. Examples may be between clients and SPs, entities such as
partners, or consortiums. There may be other cases when sharing
profiles may not be established in advance, such as an organization
dealing with an incident who requires assistance from an entity that
it has not worked with before. An organization may want to establish
sharing profiles specific to possible user groups to prepare for
possible incident scenarios. The user groups could include business
partners, industry peers, service providers, experts not part of a
service provider, law enforcement, or regulatory reporting bodies.
Workflows to approve transactions may be specific to sharing profiles
and data types. Application developers should include capabilities
to enable these decision points for users of the system.
Any expectations between entities to preserve the weight and
admissibility of evidence should be handled at the policy and
agreement level. A sharing profile may include notes or an indicator
for approvers in workflows to reflect if such agreements exist.
10. Security Considerations
RID has many security requirements and considerations built into the
design of the protocol, several of which are described in the
Security Requirements section. For a complete view of security,
considerations include the availability, confidentiality, and
integrity concerns for the transport, storage, and exchange of
information.
Protected tunnels between systems accepting RID communications are
used to provide confidentiality, integrity, authenticity, and privacy
for the data at the transport layer. Encryption and digital
signatures are also used at the IODEF document level through RID
options to provide confidentiality, integrity, authenticity, privacy
and traceability of the document contents at the application layer.
Trust relationships are based on PKI and the comparison/validation of
security controls for the incident management systems communicating
via RID. Trust levels can be established in cross-certification
processes where entities compare PKI policies that include the
specific management and handling of an entity's PKI and certificates
issued under that policy. [RFC3647] defines an Internet X.509 Public
Key Infrastructure Certificate Policy and Certification Practices
Framework that may be used in the comparison of policies to establish
trust levels and agreements between entities, an entity and a
consortium, and consortiums. The agreements SHOULD consider key
management practices including the ability to perform path validation
on certificates [RFC5280], key distribution techniques [RFC2585], and
Certificate Authority and Registration Authority management
practices.
The agreements between entities SHOULD also include a common
understanding of the usage of RID security, policy, and privacy
options discussed in both the Security Requirements and Security
Considerations sections. The formality, requirements, and complexity
of the agreements for the certificate policy, practices, supporting
infrastructure, and the use of RID options SHOULD be decided by the
entities or consortiums creating those agreements.
11. Internationalization Issues
The Node class identifies a host or network device. This document
reuses the definition of Node from the IODEF specification [RFC5070],
Section 3.16. However, that document did not clearly specify whether
a NodeName could be an Internationalized Domain Name (IDN). RID
systems MUST treat the NodeName class as a domain name slot
[RFC5890]. RID systems SHOULD support IDNs in the NodeName class.
If they do so, the UTF-8 representation of the domain name MUST be
used, i.e., all of the domain name's labels MUST be U-labels
expressed in UTF-8 or NR-LDH labels [RFC5890]; A-labels MUST NOT be
used. An application communicating via RID can convert between
A-labels and U-labels by using the Punycode encoding [RFC3492] for
A-labels as described in the protocol specification for
Internationalized Domain Names in Applications [RFC5891].
12. IANA Considerations
This document uses URNs to describe XML namespaces and XML schemas
[XMLschema] conforming to a registry mechanism described in
[RFC3688].
Registration request for the iodef-rid namespace:
URI: urn:ietf:params:xml:ns:iodef-rid-2.0
Registrant Contact: IESG.
XML: None. Namespace URIs do not represent an XML specification.
Registration request for the iodef-rid XML schema:
URI: urn:ietf:params:xml:schema:iodef-rid-2.0
Registrant Contact: IESG.
XML: See Section 8, "RID Schema Definition", of this document.
The following registry has been created and is now managed by IANA:
Name of the registry: "XML Schemas Exchanged via RID"
Namespace details: A registry entry for an XML Schema Transferred
via RID consists of:
Schema Name: A short string that represents the schema
referenced. This value is for reference only in the table.
The version of the schema MUST be included in this string to
allow for multiple versions of the same specification to be in
the registry.
Version: The version of the registered XML schema. The version
is a string that SHOULD be formatted as numbers separated by a
'.' (period) character.
Namespace: The namespace of the referenced XML schema. This is
represented in the RID ReportSchema class in the XMLSchemaID
attribute as an enumerated value is represented by a URN or
URI.
Specification URI: A URI [RFC3986] from which the registered
specification can be obtained. The specification MUST be
publicly available from this URI.
Reference: The reference to the document that describes the
schema.
Information that must be provided to assign a new value: The above
list of information.
Fields to record in the registry: Schema Name, Version, Namespace,
Specification URI, Reference
Initial registry contents: See Section 5.6.1.
Allocation Policy: Expert Review [RFC5226] and Specification
Required [RFC5226].
The Designated Expert is expected to consult with the MILE (Managed
Incident Lightweight Exchange) working group or its successor if any
such WG exists (e.g., via email to the working group's mailing list).
The Designated Expert is expected to retrieve the XML schema
specification from the provided URI in order to check the public
availability of the specification and verify the correctness of the
URI. An important responsibility of the Designated Expert is to
ensure that the XML schema is appropriate for use in RID.
The following registry has been created and is now managed by IANA:
Name of the registry: "RID Enumeration List"
The registry is intended to enable enumeration value additions to
attributes in the iodef-rid XML schema.
Fields to record in the registry: Attribute Name, Attribute Value,
Description, Reference
Initial registry content: none.
Allocation Policy: Expert Review [RFC5226]
The Designated Expert is expected to consult with the MILE (Managed
Incident Lightweight Exchange) working group or its successor if any
such WG exists (e.g., via email to the working group's mailing list).
The Designated Expert is expected to review the request and validate
the appropriateness of the enumeration for the attribute. If a
specification is associated with the request, it MUST be reviewed by
the Designated Expert.
13. Summary
Security incidents have always been difficult to trace as a result of
spoofed sources, resource limitations, and bandwidth utilization
problems. Incident response is often slow even when the IP address
is known to be valid because of the resources required to notify the
responsible party of the attack and then to stop or mitigate the
attack traffic. Methods to identify and trace attacks near real time
are essential to thwarting attack attempts. SPs need policies and
automated methods to combat the hacker's efforts. SPs need automated
monitoring and response capabilities to identify and trace attacks
quickly without resource-intensive side effects. Integration with a
centralized communication system to coordinate the detection,
tracing, and identification of attack sources on a single network is
essential. RID provides a way to integrate SP resources for each
aspect of attack detection, tracing, and source identification and
extends the communication capabilities among SPs. The communication
is accomplished through the use of flexible IODEF XML-based documents
passed between incident-handling systems or RID systems. A Request
is communicated to an upstream SP and may result in an upstream trace
or in an action to stop or mitigate the attack traffic. The messages
are communicated among peers with security inherent to the RID
messaging scheme provided through existing standards such as XML
encryption and digital signatures. Policy information is carried in
the RID message itself through the use of the RIDPolicy. RID
provides the timely communication among SPs, which is essential for
incident handling.
14. References
14.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key
Infrastructure Operational Protocols: FTP and HTTP",
RFC 2585, May 1999.
[RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media
Types", RFC 3023, January 2001.
[RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible
Markup Language) XML-Signature Syntax and Processing",
RFC 3275, March 2002.
[RFC3470] Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines
for the Use of Extensible Markup Language (XML)
within IETF Protocols", BCP 70, RFC 3470, January 2003.
[RFC3492] Costello, A., "Punycode: A Bootstring encoding of
Unicode for Internationalized Domain Names in
Applications (IDNA)", RFC 3492, March 2003.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81,
RFC 3688, January 2004.
[RFC4051] Eastlake, D., "Additional XML Security Uniform Resource
Identifiers (URIs)", RFC 4051, April 2005.
[RFC4279] Eronen, P. and H. Tschofenig, "Pre-Shared Key
Ciphersuites for Transport Layer Security (TLS)",
RFC 4279, December 2005.
[RFC5070] Danyliw, R., Meijer, J., and Y. Demchenko, "The
Incident Object Description Exchange Format", RFC 5070,
December 2007.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing
an IANA Considerations Section in RFCs", BCP 26,
RFC 5226, May 2008.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation
List (CRL) Profile", RFC 5280, May 2008.
[RFC5646] Phillips, A. and M. Davis, "Tags for Identifying
Languages", BCP 47, RFC 5646, September 2009.
[RFC5755] Farrell, S., Housley, R., and S. Turner, "An Internet
Attribute Certificate Profile for Authorization",
RFC 5755, January 2010.
[RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document
Framework", RFC 5890, August 2010.
[RFC5891] Klensin, J., "Internationalized Domain Names in
Applications (IDNA): Protocol", RFC 5891, August 2010.
[RFC6546] Trammell, B., "Transport of Real-time Inter-network
Defense (RID) Messages over HTTP/TLS", RFC 6546,
April 2012.
[XML1.0] Bray, T., Maler, E., Paoli, J., Sperberg-McQueen, C.,
and F. Yergeau, "Extensible Markup Language (XML) 1.0",
W3C Recommendation XML 1.0, November 2008,
<http://www.w3.org/TR/xml/>.
[XMLCanon] Boyer, J., "Canonical XML 1.0", W3C Recommendation 1.0,
December 2001, <http://www.w3.org/TR/xml-c14n>.
[XMLPath] Berglund, A., Boag, S., Chamberlin, D., Fernandez, M.,
Kay, M., Robie, J., and J. Simeon, "XML Schema Part 1:
Structures", W3C Recommendation Second Edition,
December 2010, <http://www.w3.org/TR/xpath20/>.
[XMLSigBP] Hirsch, F. and P. Datta, "XML-Signature Best
Practices", W3C Recommendation, August 2011,
<http://www.w3.org/TR/xmldsig-bestpractices/>.
[XMLencrypt] Imaura, T., Dillaway, B., and E. Simon, "XML Encryption
Syntax and Processing", W3C Recommendation,
December 2002, <http://www.w3.org/TR/xmlenc-core/>.
[XMLschema] Thompson, H., Beech, D., Maloney, M., and N.
Mendelsohn, "XML Schema Part 1: Structures", W3C
Recommendation Second Edition, October 2004,
<http://www.w3.org/TR/xmlschema-1/>.
[XMLsig] Bartel, M., Boyer, J., Fox, B., LaMaccia, B., and E.
Simon, "XML-Signature Syntax and Processing", W3C
Recommendation Second Edition, June 2008,
<http://www.w3.org/TR/xmldsig-core/>.
14.2. Informative References
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System
(AS)", BCP 6, RFC 1930, March 1996.
[RFC3080] Rose, M., "The Blocks Extensible Exchange Protocol
Core", RFC 3080, March 2001.
[RFC3647] Chokhani, S., Ford, W., Sabett, R., Merrill, C., and S.
Wu, "Internet X.509 Public Key Infrastructure
Certificate Policy and Certification Practices
Framework", RFC 3647, November 2003.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter,
"Uniform Resource Identifier (URI): Generic Syntax",
STD 66, RFC 3986, January 2005.
[RFC5735] Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses",
BCP 153, RFC 5735, January 2010.
[RFC6045] Moriarty, K., "Real-time Inter-network Defense (RID)",
RFC 6045, November 2010.
[RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman,
"Security Considerations for the SHA-0 and SHA-1
Message-Digest Algorithms", RFC 6194, March 2011.
[XMLNames] Bray, T., Hollander, D., Layman, A., Tobin, R., and H.
Thomson, "Namespaces in XML 1.0 (Third Edition)", W3C
Recommendation , December 2009,
<http://www.w3.org/TR/xml-names/>.
Appendix A. Acknowledgements
Many thanks to colleagues and the Internet community for reviewing
and commenting on the document as well as providing recommendations
to improve, simplify, and secure the protocol: Steve Bellovin, David
Black, Harold Booth, Paul Cichonski, Robert K. Cunningham, Roman
Danyliw, Yuri Demchenko, Sandra G. Dykes, Stephen Farrell, Katherine
Goodier, Cynthia D. McLain, Thomas Millar, Jean-Francois Morfin,
Stephen Northcutt, Damir Rajnovic, Tony Rutkowski, Peter Saint-Andre,
Jeffrey Schiller, Robert Sparks, William Streilein, Richard Struse,
Tony Tauber, Brian Trammell, Sean Turner, Iljitsch van Beijnum, and
David Waltermire.
Author's Address
Kathleen M. Moriarty
EMC Corporation
176 South Street
Hopkinton, MA
United States
EMail: Kathleen.Moriarty@emc.com