RFC 6045
Real-time Inter-network Defense (RID)
4. Communication between Network Providers
Note: The Introduction, and Sub-sections 4.1 and 4.2, are informative, with the exception of references to IODEF/RID Transport [RFC6046]. Sub-sections 4.3, 4.4, and 4.5 are normative. Expediting the communication between CSIRTs is essential when responding to a security-related incident, which may cross network access points (Internet backbones) between providers. As a result of the urgency involved in this inter-NP security incident communication, there must be an effective system in place to facilitate the interaction. This communication policy or system 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. Each NP should dedicate a phone number to reach a member of their respective CSIRT. The phone number could be dedicated to inter-NP incident communications and must be a hotline that provides a 24x7 live response. The phone line should reach someone who would have the authority, expertise, and the means to expedite the necessary action to investigate the incident. This may be a difficult policy to establish at smaller NPs due to resource limitations, so another solution may be necessary. An outside group may be able to serve this function if given the necessary access to the NP's network. The outside resource should be able to mitigate or alleviate the financial limitations and any lack of experienced resource personnel.
A technical solution to trace traffic across a single NP may include homegrown or commercial systems for which RID messaging must accommodate the input requirements. The IHS used on the NP's backbone by the CSIRT to coordinate the trace across the single network requires a method to accept and process RID messages and relay TraceRequests 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 NP would maintain its own RID/IHS and integrate with a management station used for network monitoring and analysis. An alternative for NPs lacking sufficient resources may be to have a neutral third party with access to the NP'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 the Internet as a whole or within a consortium that may be able to provide centralized resources. Consortiums would consist of a group of NPs and/or CSIRTs that agree 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 the IODEF/RID Transport [RFC6046] document. One goal of RID is to prevent the need to permit access to other networks' equipment through the use of a standard messaging mechanism to enable IHSs to communicate incident handling information to other networks 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 NPs. 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 NPs to maintain full management of their network, and the third-party option could be available to smaller NPs who lack the necessary human resources to perform incident handling operations. The first method enables the individual NPs to involve their network operations staff to authorize the continuance of a trace or other necessary response to a RID communication request through their network via a notification and alerting system. The out-of-band logical solution for messaging may be permanent virtual circuits configured with a small amount of bandwidth dedicated to RID communications between NPs. 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 between network peers who have agreed-upon use and abuse policies through the use of 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. The maintenance of the individual links is the responsibility of the two network peers hosting the link. 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 NP 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 network 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 FBI or other assisting government organization in the country of the investigation.4.1. Inter-Network Provider RID Messaging
In order to implement a messaging mechanism between RID communication systems or IHSs, a standard protocol and format is required to ensure inter-operability between vendors. The messages would have to 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 4.3 are necessary to facilitate the handling of a security incident. The message types include the Report, IncidentQuery, TraceRequest, RequestAuthorization, Result, and the Investigation request 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. An IncidentQuery message is used to request information on a particular incident. A TraceRequest message is used when the source of the traffic may have been spoofed. In that case, each network provider in the upstream path who receives a TraceRequest will issue a trace across the network to determine the upstream source of the traffic. The RequestAuthorization and Result messages are used to communicate the
status and result of a TraceRequest or Investigation request. The
Investigation request message would only involve the RID
communication systems along the path to the source of the traffic and
not the use of network trace systems. The Investigation request
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 Investigation request. A message sent
between RID systems for a TraceRequest or an Investigation request to
stop traffic at the source through a bordering network would require
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
TraceRequest containing 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 for this system and one 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 of
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 Considerations section, along
with other requirements that must be agreed upon by participating
entities.
RID requests must be legitimate security-related incidents and not used for purposes such as sabotage or censorship. An example of such abuse of the system would include 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 would enable a network manager to assess the available resources before continuing a trace. A trace initiated from a TraceRequest may cause adverse effects on a network. If the Confidence rating is low, it may not be in the NP's best interest to continue the trace. The Confidence ratings must adhere to the specifications for selecting the percentage used to avoid abuse of the system. TraceRequests must be issued by authorized individuals from the initiating network, set forth in policy guidelines established through peering or SLA.4.2. RID Network Topology
The most basic topology for communicating RID systems would be a direct connection or a bilateral relationship as illustrated below. ___________ __________ | | | | | RID |__________-------------___________| RID | |_________| | NP 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 would look 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. An example is illustrated below.
_______ _______ _______ | | | | | | __| RID |____-------------____| RID |____-------------____| RID |__ |_____| | NP Border | |_____| | NP 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 TraceRequest that may have also been unnecessary.4.3. Message Formats
Section 4.3.2 describes the six RID message types, which are based on the IODEF model [RFC5070]. The messages are generated and received on RID communication systems on the NP's network. The messages may originate from IODEF messages from intrusion detection servers, CSIRTs, analysts, etc. A RID message uses the IODEF framework with the RID extension, which is encapsulated for transport [RFC6046]. Each RID message type, along with an example, is described in the following sections. The IODEF-RID schema is introduced in Section 4.3.3 to support the RID message types in Section 4.3.2.4.3.1. 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.4.3.1.1. Boolean
A boolean value is represented by the BOOLEAN data type. The BOOLEAN data type is implemented as "xs:boolean" [XMLschema] in the schema.
4.3.2. RID Messages and Transport
The six RID message types follow: 1. TraceRequest. This message is sent to the RID system next in the upstream trace. It is 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. The TraceRequest would trigger a traceback on the network to locate the source of the attack traffic. 2. RequestAuthorization. This message is sent to the initiating RID system from each of the upstream NPs' RID systems to provide information on the request status in the current network. 3. Result. This message is sent to the initiating RID system through the network of RID systems in the path of the trace as notification that the source of the attack was located. The Result message is also used to provide the notification of actions taken for an Investigation request. 4. Investigation. This message type is used when the source of the traffic is believed not to be spoofed. The purpose of the Investigation request message is to leverage the existing peer relationships in order to notify the network provider closest to the source of the valid traffic of a security-related incident for any necessary actions to be taken. 5. 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, statistics and trending information, etc. 6. IncidentQuery. This message is used to request information about an incident or incident type from a trusted RID system. The response is provided through the Report message. When a system 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.
4.3.3. 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 TraceRequest or Investigation request; 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 acts as an envelope for the IODEF schema to facilitate RID communications. 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 that includes the IODEF schema, the RID information acts as an envelope, and then the RIDPolicy class can be easily extracted for use by the transport protocol. The security requirements of sending incident information across the network include the use of encryption. The RIDPolicy information is not required to be encrypted, so separating out this data from the IODEF extension removes the need for decrypting and parsing the entire IODEF and RID 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 policy information and guidelines are discussed in Section 6.6. The policy is defined between RID peers and within or between consortiums. The 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 | +------------------+ | ANY | | |<>---{0..1}----[ RIDPolicy ] | ENUM restriction | | ENUM type |<>---{0..1}----[ RequestStatus ] | STRING meaning | | |<>---{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 RequestAuthorization messages to report back to the originating RID system if the trace will be continued by each RID system that received a TraceRequest in the path to the source of the traffic. 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 [RFC6046], 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 [RFC6046].
4.3.3.1. RequestStatus Class
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 4. 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 REQUIRED. ENUM. The listed values are used to provide a response to the requesting CSIRT of the status of a TraceRequest in the current network. 1. Approved. The trace was approved and will begin in the current NP. 2. Denied. The trace was denied in the current NP. The next closest NP can use this message to filter traffic from the upstream NP using the example packet to help mitigate the effects of the attack as close to the source as possible. The RequestAuthorization message must be passed back to the originator and a Result message used from the closest NP to the source 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 RequestAuthorization
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 IP packet failed to validate.
4. Encryption. Unable to decrypt the request.
5. Other. There were other reasons this request could not be
processed.
6. 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.
4.3.3.2. IncidentSource Class
The IncidentSource class is an aggregate class in the RID class. +-------------------+ | IncidentSource | +-------------------+ | | | ENUM restriction | | |<>-------------[ SourceFound ] | | | |<>---{0..*}----[ Node ] | | +-------------------+ Figure 5. 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 One. The Node class is used to identify a host or network device, in this case to identify the system communicating RID messages. The base definition of this class is reused from the IODEF specification [RFC5070], Section 3.16. 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.
4.3.3.3. RIDPolicy Class
The RIDPolicy class facilitates the delivery of RID messages and is also referenced for transport in the transport document [RFC6046]. +------------------------+ | RIDPolicy | +------------------------+ | | | ENUM restriction |<>-------------[ Node ] | ENUM MsgType | | ENUM MsgDestination |<>---{0..1}----[ IncidentID ] | ENUM ext-MsgType | | ENUM ext-MsgDestination|<>---{1..*}----[ PolicyRegion ] | | | |<>---{1..*}----[ TrafficType ] | | +------------------------+ Figure 6. 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. The base definition of this class is reused from the IODEF specification [RFC5070], Section 3.16. 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 would be botnets, 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. ENUM.
1. ClientToNP. An enterprise network initiated the request.
2. NPToClient. An NP passed a RID request to a client or an
enterprise attached network to the NP based on the service
level agreements.
3. IntraConsortium. A trace that should have no restrictions
within the boundaries of a consortium with the agreed-upon use
and abuse guidelines.
4. PeerToPeer. A trace 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.
5. BetweenConsortiums. A trace that should have no restrictions
between consortiums that have established agreed-upon use and
abuse guidelines.
6. AcrossNationalBoundaries. This selection must be set if the
trace type is anything but a trace of attack traffic with
malicious intent. This must also be set if the traffic request
is based upon regulations of a specific nation that would not
apply to all nations. This is different from the
"BetweenConsortiums" setting since it may be possible to have
multiple nations as members of the same consortium, and this
option must be selected if the traffic is of a type that may
have different restrictions in other nations.
7. 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
NP 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 would most accurately
describe the traffic type.
type
One. ENUM.
1. Attack. This option should only be selected if the traffic is
related to a network-based 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 NP 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 include determining what sources or
destinations accessed certain materials available on the
Internet, including, but not limited to, news, technology, or
inappropriate content.
4. OfficialBusiness. This option MUST be used if the traffic
being traced is requested or is affiliated with any government
or other official business request. This would be used during
an investigation by government authorities or other government
traces to track suspected criminal or other activities.
5. 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 trace. The information should be
provided in the IODEF message in the Expectation class or in
the History class using a HistoryItem log.
6. ext-value. An escape value used to extend this attribute. See
IODEF [RFC5070], Section 5.1.
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
REQUIRED. ENUM. The type of RID message sent. The six types of
messages are described in Section 4.3.2 and can be noted as one of
the six selections below.
1. TraceRequest. This 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. RequestAuthorization. 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. Investigation. This message type is used when the source of
the traffic is believed to be valid. The purpose of the
Investigation request is to leverage the existing peer or
consortium relationships in order to notify the NP 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, statistics and trending information,
etc.
6. IncidentQuery. 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
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 an Investigation request, the source
of the incident. In the case of an Investigation request, 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 address listed in the Node element of the
RIDPolicy class is the next upstream RID system that will
receive the RID message.
2. SourceOfIncident. The address listed in the Node element of
the RIDPolicy class is the incident source. The IP address is
used to determine the path of RID systems 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
an Investigation request message is used. This is not to be
confused with the IncidentSource class, as the defined value
here is from an initial trace or Investigation request, not the
source used in a Result message.
3. ext-value. An escape value used to extend this attribute. See
IODEF [RFC5070], Section 5.1.
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.
4.3.4. RID Namespace
The RID schema declares a namespace of "iodef-rid-1.0" and registers it per [XMLnames]. Each IODEF-RID document MUST use the "iodef- rid-1.0" namespace in the top-level element RID-Document. It can be referenced as follows: <RID-Document version="1.00" lang="en-US" xmlns:iodef-rid="urn:ietf:params:xml:ns:iodef-rid-1.0" xsi:schemaLocation=http://www.iana.org/assignments/xml-registry/ schema/iodef-rid-1.0.xsd">4.4. 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 to ensure proper parsing of all RID messages. Note: The implementation of the RID system may obtain some of the information needed to fill in the content required for each message type automatically from packet input to the system or default information such as that used in the EventData class.4.4.1. TraceRequest
Description: This message or document is sent to the network management station next in the upstream trace once the upstream source of the traffic has been identified. The following information is required for TraceRequest messages and is provided through: RID Information: RIDPolicy RID message type, IncidentID, and destination policy information IODEF Information: Time Stamps (DetectTime, StartTime, EndTime, ReportTime).
Incident Identifier (Incident class, IncidentID).
Trace number - used for multiple traces of a single
incident; must be noted.
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 an upstream TraceRequest in RID.
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 NP
path contact information.
Standards for encryption and digital signatures [RFC3275],
[XMLsig]:
Digital signature from initiating RID system, passed to all
systems in upstream trace using XML digital signature.
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 would
enable the administrators to determine if the exact trace had already
passed through a single network. The Incident Identifier must also
be used to identify multiple TraceRequests from a single incident.
If a single TraceRequest results in divergent paths of TraceRequests,
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.
4.4.2. RequestAuthorization
Description: This message is sent to the initiating RID system from
the next upstream NP's RID system to provide information on the
request status in the current network.
The following information is required for RequestAuthorization
messages and is provided through:
RID Information:
RIDPolicy
RID message type, IncidentID, and destination
policy information
Status of TraceRequest
RequestStatus class in RID schema
Standards for encryption and digital signatures [RFC3275],
[XMLsig]:
Digital signature of responding NP for authenticity of Trace
Status Message, from the NP creating this message using XML
digital signature.
A message is sent back to the initiating RID system 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 RID system. The
Pending status would be automatically generated after a 2-minute
timeout without system-predefined or administrator action taken 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 enables the sending peer the option to
take action to stop or mitigate the traffic as close to the source as
possible.
4.4.3. 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 through the IncidentSource class. The Result
information MUST go back to the originating RID system that began the
investigation or trace. An NP 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:
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).
IODEF Information:
Time Stamps (DetectTime, StartTime, EndTime, ReportTime).
Incident Identifier (Incident class, IncidentID).
Trace number - used for multiple traces of a single
incident; must be noted.
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 an upstream TraceRequest in RID.
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 NP listed
is the NP that located the source of the traffic (the NP
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 NP
path contact information.
Standards for encryption and digital signatures [RFC3275]:
Digital signature of source NP for authenticity of Result
Message, from the NP creating this message using XML digital
signature.
A message is sent back to the initiating RID system to notify the
associated 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 NP to act upon the discovery of the source of a trace
should be included. The NP 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 enough to block all Internet access until the host has
taken the appropriate action to resolve any security issues or to
rate-limit the ingress traffic as close to the source as possible.
Security and privacy considerations discussed in Section 6 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 TraceRequest or
Investigation 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 TraceRequest or Investigation
request is made.
4.4.4. Investigation Request
Description: This message type is used when the source of the traffic
is believed not to be spoofed. The purpose of the Investigation
request message is to leverage the existing bilateral peer
relationships in order to notify the network provider closest to the
source of the valid traffic that some event occurred, which may be a
security-related incident.
The following information is required for Investigation request
messages and is provided through:
RID Information:
RID Policy
RID message type, IncidentID, and destination
policy information
IODEF Information:
Time Stamps (DetectTime, StartTime, EndTime, ReportTime).
Incident Identifier (Incident class, IncidentID).
Trace number - used for multiple traces of a single
incident; must be noted.
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 an upstream TraceRequest in RID.
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 NP
path contact information.
Standards for encryption and digital signatures [RFC3275]:
Digital signature from initiating RID system, passed to all
systems in upstream trace using XML digital signature.
Security considerations would include the ability to encrypt
[XMLencrypt] the contents of the Investigation request message using
the public key of the destination RID system. The incident number
would increase as if it were a TraceRequest message in order to
ensure uniqueness within the system. The relaying peers would also
append their Autonomous System (AS) or RID system information as the
request message was relayed along the web of network providers so
that the Result message could utilize the same path as the set of
trust relationships for the return message, thus indicating any
actions taken. The request would also be recorded in the state
tables of both the initiating and destination NP RID systems. The
destination NP is responsible for any actions taken as a result of
the request in adherence to any service level agreements or internal
policies. The NP should 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 message destination of RIDPolicy, SourceOfIncident. Note: All intermediate parties must be able to view RIDPolicy information in order to properly direct RID messages.4.4.5. 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: RID Information: RID Policy RID message type, IncidentID, and destination policy information The following data is recommended if available and can be provided through: IODEF Information: Time Stamps (DetectTime, StartTime, EndTime, ReportTime). Incident Identifier (Incident class, IncidentID). Trace number - used for multiple traces of a single incident; must be noted. 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 to include example packets and other information related to the incident (optional). Standards for encryption and digital signatures [RFC3275]: Digital signature from initiating RID system, passed to all systems receiving the report using XML digital signature.
Security considerations would 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 in response to an IncidentQuery, and data sensitivity must be considered in both cases. The NP path information is not necessary for this message, as it will be communicated directly between two trusted RID systems.4.4.6. IncidentQuery
Description: The IncidentQuery 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 IncidentQuery, the return report may be automated; otherwise, analyst intervention may be required. The following information must be used for an IncidentQuery message and is provided through: RID Information: RID Policy RID message type, IncidentID, and destination policy information IODEF Information (optional): Time Stamps (DetectTime, StartTime, EndTime, ReportTime). Incident Identifier (Incident class, IncidentID). Trace number - used for multiple traces of a single incident; must be noted. 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 to include example
packets and other information related to the incident
(optional).
Standards for encryption and digital signatures [RFC3275]:
Digital signature from initiating RID system, passed to all
systems receiving the IncidentQuery using XML digital
signature. If a packet is not included, the signature may be
based on the RIDPolicy class.
The proper response to the IncidentQuery 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 would send an
IODEF document containing multiple incidents or all instances of an
incident. The system sending the reply may pre-set 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 suited better than RID for large transfers of
data. The Confidence rating may be used in the IncidentQuery 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 IncidentQuery is intended to gather data about a specific type of
incident as well.
(page 37 continued on part 3)
