Expectations for Computer Security Incident Response
draft-ietf-grip-framework-irt-07
The information below is for an old version of the document that is already published as an RFC.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 2350.
|
|
|---|---|---|---|
| Authors | Erik Guttman , Nevil Brownlee | ||
| Last updated | 2013-03-02 (Latest revision 1997-09-11) | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Best Current Practice | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | (None) | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 2350 (Best Current Practice) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-grip-framework-irt-07
Internet Engineering Task Force (IETF) H. Asaeda
Request for Comments: 8487 NICT
Category: Standards Track K. Meyer
ISSN: 2070-1721 Dell EMC
W. Lee, Ed.
October 2018
Mtrace Version 2: Traceroute Facility for IP Multicast
Abstract
This document describes the IP multicast traceroute facility, named
Mtrace version 2 (Mtrace2). Unlike unicast traceroute, Mtrace2
requires special implementations on the part of routers. This
specification describes the required functionality in multicast
routers, as well as how an Mtrace2 client invokes a Query and
receives a Reply.
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 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8487.
Asaeda, et al. Standards Track [Page 1]
understand the background and set-up of the CSIRT, and it is vital
information for building trust between a constituent and a CSIRT.
3.3.4 Authority
This section will vary greatly from one CSIRT to another, based on
the relationship between the team and its constituency. While an
organizational CSIRT will be given its authority by the management
of the organization, a community CSIRT will be supported and chosen
by the community, usually in a advisory role.
A CSIRT may or may not have the authority to intervene in the
operation of all of the systems within its perimeter. It should
identify the scope of its control as distinct from the perimeter of
its constituency. If other CSIRTs operate hierarchically within its
perimeter, this should be mentioned here, and the related CSIRTs
identified.
Disclosure of a team's authority may expose it to claims of
liability. Every team should seek legal advice on these matters.
(See section 3.7 for more on liability.)
3.4 Policies
It is critical that Incident Response Teams define their policies.
The following sections discuss communication of these policies to
the constituent community.
3.4.1 Types of Incidents and Level of Support
The types of incident which the team is able to address, and the
level of support which the team will offer when responding to each
type of incident, should be summarized here in list form. The
Services section (see below) provides the opportunity to give more
detailed descriptions, and to address non-incident-related topics.
The level of support may change depending on factors such as the
team's workload and the completeness of the information available.
Such factors should be outlined and their impact should be
explained. As a list of known types of incidents will be incomplete
with regard to possible or future incidents, a CSIRT should also give
some background on the "default" support for incident types not
otherwise mentioned.
The team should state whether it will act on information it receives
about vulnerabilities which create opportunities for future
incidents. A commitment to act on such information on behalf of its
constituency is regarded as an optional proactive service policy
rather than a core service requirement for a CSIRT.
Brownlee, Guttman Internet Draft [Page 10]
Expectations for Computer Security Incident Response 11 September 97
3.4.2 Co-operation, Interaction and Disclosure of Information
This section should make explicit which related groups the CSIRT
routinely interacts with. Such interactions are not necessarily
related to the computer security incident response provided, but are
used to facilitate better cooperation on technical topics or
services. By no means need details about cooperation agreements be
given out; the main objective of this section is to give the
constituency a basic understanding of what kind of interactions are
established and what their purpose is.
The reporting and disclosure policy should make clear who will be
the recipients of a CSIRT's report in each circumstance. It should
also note whether the team will expect to operate through another
CSIRT or directly with a member of another constituency over matters
specifically concerning that member.
Important examples of related groups a CSIRT will interact with are
listed below.
Incident Response Teams:
A CSIRT will often need to interact with other CSIRTs. For
example a CSIRT within a large company may need to report
incidents to a national CSIRT, and a national CSIRT may need to
report incidents to national CSIRTs in other countries to deal
with all sites involved in a large-scale attack.
Collaboration between CSIRTs may lead to disclosure of
information. The following are examples of such disclosure,
but are not intended to be an exhaustive list:
- Reporting incidents within the constituency to other teams.
If this is done, site-related information may become public
knowledge, accessible to everyone, in particular the press.
- Handling incidents occurring within the constituency, but
reported from outside it (which implies that some information
has already been disclosed off-site).
- Reporting observations from within the constituency indicating
suspected or confirmed incidents outside it.
- Acting on reports of incidents occurring outside the
constituency.
- Passing information about vulnerabilities to vendors, to
partner CSIRTs or directly to affected sites lying within or
outside the constituency.
- Feedback to parties reporting incidents or vulnerabilities.
Brownlee, Guttman Internet Draft [Page 11]
Expectations for Computer Security Incident Response 11 September 97
- The provision of contact information relating to members of
the constituency, members of other constituencies, other
CSIRTs, or law-enforcement agencies.
Vendors:
Some vendors have their own CSIRTs, but some vendors may not.
In such cases a CSIRT will need to work directly with a vendor to
suggest improvements or modifications, to analyse the technical
problem or to test provided solutions. Vendors play a special
role in handling an incident if their products' vulnerabilities
are involved in the incident.
Law-enforcement agencies:
These include the police and other investigative agencies. CSIRTs
and users of the template should be sensitive to local laws and
regulations, which may vary considerably in different countries.
A CSIRT might advise on technical details of attacks or seek
advice on the legal implications of an incident. Local laws and
regulations may include specific reporting and confidentiality
requirements.
Press:
A CSIRT may be approached by the press for information and
comment from time to time.
An explicit policy concerning disclosure to the press can be
helpful, particularly in clarifying the expectations of a CSIRT's
constituency. The press policy will have to clarify the same
topics as above more specifically, as the constituency will
usually be very sensitive to press contacts.
Other:
This might include research activities or the relation to the
sponsoring organization.
The default status of any and all security-related information which
a team receives will usually be 'confidential,' but rigid adherence
to this makes the team to appear to be an informational 'black
hole,' which may reduce the likelihood of the team's obtaining
cooperation from clients and from other organizations. The CSIRT's
template should define what information it will report or disclose,
to whom, and when.
Different teams are likely to be subject to different legal
restraints requiring or limiting disclosure, especially if they work
in different jurisdictions. In addition, they may have reporting
requirements imposed by their sponsoring organization. Each team's
template should specify any such constraints, both to clarify users'
expectations and to inform other teams.
Conflicts of interest, particularly in commercial matters, may also
restrain disclosure by a team; this document does not recommend on
how such conflicts should be addressed.
Brownlee, Guttman Internet Draft [Page 12]
Expectations for Computer Security Incident Response 11 September 97
A team will normally collect statistics. If statistical information
is distributed, the template's reporting and disclosure policy
should say so, and should describe how to obtain such statistics.
3.4.3 Communication and Authentication
You must have a policy which describes methods of secure and
verifiable communication that you will use. This is necessary for
communication between CSIRTs and between a CSIRT and its
constituents. The template should include public keys or pointers
to them, including key fingerprints, together with guidelines on how
to use this information to check authenticity and how to deal with
corrupted information (for example where to report this fact).
At the moment it is recommended that as a minimum every CSIRT have
(if possible), a PGP key available. A team may also
make other mechanisms available (for example PEM, MOSS, S/MIME),
according to its needs and the needs of its constituents. Note
however, that CSIRTs and users should be sensitive to local laws and
regulations. Some countries do not allow strong encryption, or
enforce specific policies on the use of encryption technology. In
addition to encrypting sensitive information whenever possible,
correspondence should include digital signatures. (Please note that
in most countries, the protection of authenticity by using digital
signatures is not affected by existing encryption regulations.)
For communication via telephone or facsimile a CSIRT may keep secret
authentication data for parties with whom they may deal, such as an
agreed password or phrase. Obviously, such secret keys must not be
published, though their existence may be.
3.5 Services
Services provided by a CSIRT can be roughly divided into two
categories: real-time activities directly related to the main task
of incident response, and non-real-time proactive activities,
supportive of the incident response task. The second category and
part of the first category consist of services which are optional
in the sense that not all CSIRTs will offer them.
3.5.1 Incident Response
Incident response usually includes assessing incoming reports about
incidents ("Incident Triage") and following up on these with other
CSIRTs, ISPs and sites ("Incident Coordination"). A third range of
services, helping a local site to recover from an incident
("Incident Resolution"), is comprised of typically optional
services, which not all CSIRTs will offer.
Brownlee, Guttman Internet Draft [Page 13]
Expectations for Computer Security Incident Response 11 September 97
3.5.1.1 Incident Triage
Incident triage usually includes:
- Report assessment Interpreting incoming incident
reports, prioritizing them,and
relating them to ongoing incidents
and trends.
- Verification Help in determining whether an
incident has really occurred, and
its scope.
3.5.1.2 Incident Coordination
Incident Coordination normally includes:
- Information categorization Categorization the incident related
information (logfiles, contact
information, etc.) with respect to
the information disclosure policy.
- Coordination Notification of other involved
parties on a need-to-know basis, as
per the information disclosure
policy.
3.5.1.3 Incident Resolution
Usually additional or optional, incident resolution services
include:
- Technical Assistance This may include analysis of
compromised systems.
- Eradication Elimination of the cause of a
security incident (the vulnerability
exploited), and its effects (for
example, continuing access to the
system by an intruder).
- Recovery Aid in restoring affected systems
and services to their status before
the security incident.
Brownlee, Guttman Internet Draft [Page 14]
Expectations for Computer Security Incident Response 11 September 97
RFC 8487 Mtrace2 October 2018
Copyright Notice
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it for publication as an RFC or to translate it into languages other
than English.
Asaeda, et al. Standards Track [Page 2]
RFC 8487 Mtrace2 October 2018
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 7
3. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Mtrace2 TLV Format . . . . . . . . . . . . . . . . . . . 9
3.2. Defined TLVs . . . . . . . . . . . . . . . . . . . . . . 10
3.2.1. Mtrace2 Query . . . . . . . . . . . . . . . . . . . . 10
3.2.2. Mtrace2 Request . . . . . . . . . . . . . . . . . . . 12
3.2.3. Mtrace2 Reply . . . . . . . . . . . . . . . . . . . . 12
3.2.4. IPv4 Mtrace2 Standard Response Block . . . . . . . . 13
3.2.5. IPv6 Mtrace2 Standard Response Block . . . . . . . . 18
3.2.6. Mtrace2 Augmented Response Block . . . . . . . . . . 20
3.2.7. Mtrace2 Extended Query Block . . . . . . . . . . . . 21
4. Router Behavior . . . . . . . . . . . . . . . . . . . . . . . 22
4.1. Receiving an Mtrace2 Query . . . . . . . . . . . . . . . 22
4.1.1. Query Packet Verification . . . . . . . . . . . . . . 22
4.1.2. Query Normal Processing . . . . . . . . . . . . . . . 23
4.2. Receiving an Mtrace2 Request . . . . . . . . . . . . . . 23
4.2.1. Request Packet Verification . . . . . . . . . . . . . 24
4.2.2. Request Normal Processing . . . . . . . . . . . . . . 24
4.3. Forwarding Mtrace2 Request . . . . . . . . . . . . . . . 26
4.3.1. Destination Address . . . . . . . . . . . . . . . . . 26
4.3.2. Source Address . . . . . . . . . . . . . . . . . . . 26
4.3.3. Appending Standard Response Block . . . . . . . . . . 26
4.4. Sending Mtrace2 Reply . . . . . . . . . . . . . . . . . . 27
4.4.1. Destination Address . . . . . . . . . . . . . . . . . 27
4.4.2. Source Address . . . . . . . . . . . . . . . . . . . 27
4.4.3. Appending Standard Response Block . . . . . . . . . . 27
4.5. Proxying Mtrace2 Query . . . . . . . . . . . . . . . . . 28
4.6. Hiding Information . . . . . . . . . . . . . . . . . . . 28
5. Client Behavior . . . . . . . . . . . . . . . . . . . . . . . 29
5.1. Sending Mtrace2 Query . . . . . . . . . . . . . . . . . . 29
5.1.1. Destination Address . . . . . . . . . . . . . . . . . 29
5.1.2. Source Address . . . . . . . . . . . . . . . . . . . 29
5.2. Determining the Path . . . . . . . . . . . . . . . . . . 29
5.3. Collecting Statistics . . . . . . . . . . . . . . . . . . 29
5.4. Last-Hop Router (LHR) . . . . . . . . . . . . . . . . . . 30
5.5. First-Hop Router (FHR) . . . . . . . . . . . . . . . . . 30
5.6. Broken Intermediate Router . . . . . . . . . . . . . . . 30
5.7. Non-supported Router . . . . . . . . . . . . . . . . . . 30
5.8. Mtrace2 Termination . . . . . . . . . . . . . . . . . . . 31
5.8.1. Arriving at Source . . . . . . . . . . . . . . . . . 31
5.8.2. Fatal Error . . . . . . . . . . . . . . . . . . . . . 31
5.8.3. No Upstream Router . . . . . . . . . . . . . . . . . 31
5.8.4. Reply Timeout . . . . . . . . . . . . . . . . . . . . 31
5.9. Continuing after an Error . . . . . . . . . . . . . . . . 31
Asaeda, et al. Standards Track [Page 3]
RFC 8487 Mtrace2 October 2018
6. Protocol-Specific Considerations . . . . . . . . . . . . . . 32
6.1. PIM-SM . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.2. Bidirectional PIM . . . . . . . . . . . . . . . . . . . . 32
6.3. PIM-DM . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.4. IGMP/MLD Proxy . . . . . . . . . . . . . . . . . . . . . 33
7. Problem Diagnosis . . . . . . . . . . . . . . . . . . . . . . 33
7.1. Forwarding Inconsistencies . . . . . . . . . . . . . . . 33
7.2. TTL or Hop-Limit Problems . . . . . . . . . . . . . . . . 33
7.3. Packet Loss . . . . . . . . . . . . . . . . . . . . . . . 33
7.4. Link Utilization . . . . . . . . . . . . . . . . . . . . 34
7.5. Time Delay . . . . . . . . . . . . . . . . . . . . . . . 34
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
8.1. "Mtrace2 Forwarding Codes" Registry . . . . . . . . . . . 35
8.2. "Mtrace2 TLV Types" Registry . . . . . . . . . . . . . . 35
8.3. UDP Destination Port . . . . . . . . . . . . . . . . . . 35
9. Security Considerations . . . . . . . . . . . . . . . . . . . 35
9.1. Addresses in Mtrace2 Header . . . . . . . . . . . . . . . 35
9.2. Verification of Clients and Peers . . . . . . . . . . . . 35
9.3. Topology Discovery . . . . . . . . . . . . . . . . . . . 36
9.4. Characteristics of Multicast Channel . . . . . . . . . . 36
9.5. Limiting Query/Request Rates . . . . . . . . . . . . . . 37
9.6. Limiting Reply Rates . . . . . . . . . . . . . . . . . . 37
9.7. Specific Security Concerns . . . . . . . . . . . . . . . 37
9.7.1. Request and Response Bombardment . . . . . . . . . . 37
9.7.2. Amplification Attack . . . . . . . . . . . . . . . . 37
9.7.3. Leaking of Confidential Topology Details . . . . . . 38
9.7.4. Delivery of False Information (Forged Reply Messages) 38
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 39
10.1. Normative References . . . . . . . . . . . . . . . . . . 39
10.2. Informative References . . . . . . . . . . . . . . . . . 40
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 41
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41
Asaeda, et al. Standards Track [Page 4]
RFC 8487 Mtrace2 October 2018
1. Introduction
Given a multicast distribution tree, tracing hop-by-hop downstream
from a multicast source to a given multicast receiver is difficult
because there is no efficient and deterministic way to determine the
branch of the multicast routing tree on which that receiver lies. On
the other hand, walking up the tree from a receiver to a source is
easy, as most existing multicast routing protocols know the upstream
router for each source. Tracing from a receiver to a source can
involve only the routers on the direct path.
This document specifies the multicast traceroute facility named
Mtrace version 2 or Mtrace2, which allows the tracing of an IP
multicast routing path. Mtrace2 is usually initiated from an Mtrace2
client by sending an Mtrace2 Query to a Last-Hop Router (LHR) or to a
Rendezvous Point (RP). The RP is a special router where sources and
receivers meet in Protocol Independent Multicast - Sparse Mode
(PIM-SM) [5]. From the LHR/RP receiving the Query, the tracing is
directed towards a specified source if a source address is specified
and a source-specific state exists on the receiving router. If no
source address is specified or if no source-specific state exists on
a receiving LHR, the tracing is directed toward the RP for the
specified group address. Moreover, Mtrace2 provides additional
information such as the packet rates and losses, as well as other
diagnostic information. Mtrace2 is primarily intended for the
following purposes:
o To trace the path that a packet would take from a source to a
receiver.
o To isolate packet-loss problems (e.g., congestion).
o To isolate configuration problems (e.g., Time to live (TTL)
threshold).
The following figure shows a typical case of how Mtrace2 is used.
FHR represents the first-hop router, LHR represents the last-hop
router, and the arrow lines represent the Mtrace2 messages that are
sent from one node to another. The numbers before the Mtrace2
messages represent the sequence of the messages that would happen.
The source, receiver, and Mtrace2 client are typically hosts.
Asaeda, et al. Standards Track [Page 5]
RFC 8487 Mtrace2 October 2018
2. Request 2. Request
+----+ +----+
| | | |
v | v |
+--------+ +-----+ +-----+ +----------+
| Source |----| FHR |----- The Internet -----| LHR |----| Receiver |
+--------+ +-----+ | +-----+ +----------+
\ | ^
\ | /
\ | /
\ | /
3. Reply \ | / 1. Query
\ | /
\ | /
\ +---------+ /
v | Mtrace2 |/
| Client |
+---------+
When an Mtrace2 client initiates a multicast trace, it sends an
Mtrace2 Query packet to an LHR or RP for a multicast group and,
optionally, a source address. The LHR/RP turns the Query packet into
a Request. The Request message type enables each of the upstream
routers processing the message to apply different packet and message
validation rules than those required for the handling of a Query
message. The LHR/RP then appends a Standard Response Block
containing its interface addresses and packet statistics to the
Request packet, then forwards the packet towards the source/RP. The
Request packet is either unicasted to its upstream router towards the
source/RP or multicasted to the group if the upstream router's IP
address is not known. In a similar fashion, each router along the
path to the source/RP appends a Standard Response Block to the end of
the Request packet before forwarding it to its upstream router. When
the FHR receives the Request packet, it appends its own Standard
Response Block, turns the Request packet into a Reply, and unicasts
the Reply back to the Mtrace2 client.
The Mtrace2 Reply may be returned before reaching the FHR under some
circumstances. This can happen if a Request packet is received at an
RP or gateway, or when any of several types of error or exception
conditions occur that prevent the sending of a Request to the next
upstream router.
The Mtrace2 client waits for the Mtrace2 Reply message and displays
the results. When not receiving an Mtrace2 Reply message due to
network congestion, a broken router (see Section 5.6), or a non-
responding router (see Section 5.7), the Mtrace2 client may resend
another Mtrace2 Query with a lower hop count (see Section 3.2.1) and
Asaeda, et al. Standards Track [Page 6]
RFC 8487 Mtrace2 October 2018
repeat the process until it receives an Mtrace2 Reply message. The
details are specific to the Mtrace2 client and outside the scope of
this document.
Note that when a router's control plane and forwarding plane are out
of sync, the Mtrace2 Requests might be forwarded based on the control
states instead. In this case, the traced path might not represent
the real path the data packets would follow.
Mtrace2 supports both IPv4 and IPv6. Unlike the previous version of
Mtrace, which implements its query and response as Internet Group
Management Protocol (IGMP) messages [10], all Mtrace2 messages are
UDP based. Although the packet formats of IPv4 and IPv6 Mtrace2 are
different because of the address families, the syntax between them is
similar.
This document describes the base specification of Mtrace2 that can
serve as a basis for future proposals such as Mtrace2 for Automatic
Multicast Tunneling (AMT) [16] and Mtrace2 for Multicast in MPLS/BGP
IP VPNs (known as Multicast VPN (MVPN)) [15]. They are, therefore,
out of the scope of this document.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL
3.5.2. Proactive Activities
Usually additional or optional, proactive services might include:
- Information provision This might include an archive of
known vulnerabilities, patches or
resolutions of past problems, or
advisory mailing lists.
- Security Tools This may include tools for auditing
a Site's security.
- Education and training
- Product evaluation
- Site security auditing and consulting
3.6 Incident Reporting Forms
The use of reporting forms makes it simpler for both users and
teams to deal with incidents. The constituent can prepare answers
to various important questions before he or she actually contacts
the team, and can therefore come well prepared. The team gets all
the necessary information at once with the first report and can
proceed efficiently.
Depending on the objectives and services of a particular CSIRT,
multiple forms may be used, for example a reporting form for a new
vulnerability may be very different from the form used for reporting
incidents.
It is most efficient to provide forms through the online information
services of the team. The exact pointers to them should be given in
the CSIRT description document, together with statements about
appropriate use, and guidelines for when and how to use the forms.
If separate e-mail addresses are supported for form-based reporting,
they should be listed here again.
One example of such a form is the Incident Reporting Form provided
by the CERT Coordination Center:
- ftp://info.cert.org/incident_reporting_form
3.7 Disclaimers
Although the CSIRT description document does not constitute a
contract, liability may conceivably result from its descriptions of
services and purposes. The inclusion of a disclaimer at the end of
the template is therefore recommended and should warn the user about
possible limitations.
Brownlee, Guttman Internet Draft [Page 15]
Expectations for Computer Security Incident Response 11 September 97
In situations where the original version of a document must be
translated into another language, the translation should carry a
disclaimer and a pointer to the original. For example:
Although we tried to carefully translate the original
document from German into English, we can not be certain
that both documents express the same thoughts in the same
level of detail and correctness. In all cases, where there
is a difference between both versions, the German version
will prevail.
The use of and protection by disclaimers is affected by local laws
and regulations, of which each CSIRT should be aware. If in doubt
the CSIRT should check the disclaimer with a lawyer.
Appendix A: Glossary of Terms
This glossary defines terms used in describing security incidents
and Computer Security Incident Response Teams. Only a limited list
is included. For more definitions please refer to other sources,
for example to the Internet User's Glossary [RFC 1983].
Constituency:
Implicit in the purpose of a Computer Security Incident Response
Team is the existence of a constituency. This is the group of
users, sites, networks or organizations served by the team. The
team must be recognized by its constituency in order to be
effective.
Security Incident:
For the purpose of this document, this term is a synonym of
Computer Security Incident: any adverse event which compromises
some aspect of computer or network security.
The definition of an incident may vary between organizations, but
at least the following categories are generally applicable:
- Loss of confidentiality of information.
- Compromise of integrity of information.
- Denial of service.
- Misuse of service, systems or information.
- Damage to systems.
These are very general categories. For instance the replacement
of a system utility program by a Trojan Horse is an example of
'compromise of integrity,' and a successful password attack is an
example of 'loss of confidentiality.' Attacks, even if they
failed because of proper protection, can be regarded as
Incidents.
Within the definition of an incident the word 'compromised' is
Brownlee, Guttman Internet Draft [Page 16]
Expectations for Computer Security Incident Response 11 September 97
used. Sometimes an administrator may only 'suspect' an incident.
During the response it must be established whether or not an
incident has really occurred.
Computer Security Incident Response Team:
Based on two of the definitions given above, a CSIRT is a team
that coordinates and supports the response to security incidents
that involve sites within a defined constituency.
In order to be considered a CSIRT, a team must:
- Provide a (secure) channel for receiving reports about
suspected incidents.
- Provide assistance to members of its constituency in
handling these incidents.
- Disseminate incident-related information to its
constituency and to other involved parties.
Note that we are not referring here to police or other law
enforcement bodies which may investigate computer-related crime.
CSIRT members, indeed, need not have any powers beyond
those of ordinary citizens.
Vendor:
A 'vendor' is any entity that produces networking or computing
technology, and is responsible for the technical content of that
technology. Examples of 'technology' include hardware (desktop
computers, routers, switches, etc.), and software (operating
systems, mail forwarding systems, etc.).
Note that the supplier of a technology is not necessarily the
'vendor' of that technology. As an example, an Internet Service
Provider (ISP) might supply routers to each of its customers, but
the 'vendor' is the manufacturer, since the manufacturer, rather
than the ISP, is the entity responsible for the technical content
of the router.
Vulnerability:
A 'vulnerability' is a characteristic of a piece of technology
which can be exploited to perpetrate a security incident. For
example, if a program unintentionally allowed ordinary users to
execute arbitrary operating system commands in privileged mode,
this "feature" would be a vulnerability.
Brownlee, Guttman Internet Draft [Page 17]
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Appendix B: Related Material
Important issues in responding to security incidents on a site level
are contained in [RFC 1244], the Site Security Handbook, produced by
the Site Security Handbook Working Group (SSH). This document will
be updated by the SSH working group and will give recommendations
for local policies and procedures, mainly related to the avoidance
of security incidents.
Other documents of interest for the discussion of CSIRTs and their
tasks are available by anonymous FTP. A collection can be found on:
- ftp://ftp.cert.dfn.de/pub/docs/csir/
Please refer to file 01-README for further information about
the content of this directory.
Some especially interesting documents in relation to this document
are as follows:
- ftp://ftp.nic.surfnet.nl/surfnet/net-security/cert-nl/docs/
reports/R-92-01
This report contains the Operational Framework of CERT-NL, the
CSIRT of SURFnet (network provider in the Netherlands).
- For readers interested in the operation of FIRST (Forum of
Incident Response and Security Teams) more information is
collected in Appendix C.
- http://hightop.nrl.navy.mil/news/incident.html
This document leads to the NRL Incident Response Manual.
- http://www.cert.dfn.de/eng/team/kpk/certbib.html
This document contains an annotated bibliography of available
material, documents and files about the operation of CSIRTs
with links to many of the referenced items.
- ftp://info.cert.org/incident_reporting_form
This Incident Reporting Form is provided by the CERT
Coordination Center to gather incident information and to avoid
additional delays caused by the need to request more detailed
information from the reporting site.
- http://www.cert.org/cert.faqintro.html
A collection of frequently asked questions from the CERT
Coordination Center.
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Appendix C: Known Computer Security Incident Response Teams
Today, there are many different CSIRTs but no single source lists
every team. Most of the major and long established teams (the first
CSIRT was founded in 1988) are nowadays members of FIRST, the
worldwide Forum of Incident Response and Security Teams. At the
time of writing, more than 55 teams are members (1 in Australia, 13
in Europe, all others in North America). Information about FIRST
can be found:
- http://www.first.org/
The current list of members is available also, with the relevant
contact information and some additional information provided by the
particular teams:
- http://www.first.org/team-info/
For CSIRTs which want to become members of this forum (please note
that a team needs a sponsor - a team which is already a full member
of FIRST - to be introduced), the following files contain more
information:
- http://www.first.org/about/op_frame.html
The Operational Framework of FIRST.
- http://www.first.org/docs/newmem.html
Guidelines for teams which want to become members of FIRST.
Many of the European teams, regardless of whether they are members
of FIRST or not, are listed by countries on a page maintained by
the German CSIRT:
- http://www.cert.dfn.de/eng/csir/europe/certs.html
To learn about existing teams suitable to one's needs it is
often helpful to ask either known teams or an Internet Service
Provider for the "right" contact.
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Appendix D: Outline for CSIRT Template
This outline summarizes in point form the issues addressed in this
document, and is the recommended template for a CSIRT description
document. Its structure is designed to facilitate the communication
of a CSIRT's policies, procedures, and other relevant information to
its constituency and to outside organizations such as other CSIRTs.
A 'filled-in' example of this template is given as Appendix E.
1. Document Information
1.1 Date of Last Update
1.2 Distribution List for Notifications
1.3 Locations where this Document May Be Found
2. Contact Information
2.1 Name of the Team
2.2 Address
2.3 Time Zone
2.4 Telephone Number
2.5 Facsimile Number
2.6 Other Telecommunication
2.7 Electronic Mail Address
2.8 Public Keys and Encryption Information
2.9 Team Members
2.10 Other Information
2.11 Points of Customer Contact
3. Charter
3.1 Mission Statement
3.2 Constituency
3.3 Sponsorship and/or Affiliation
3.4 Authority
4. Policies
4.1 Types of Incidents and Level of Support
4.2 Co-operation, Interaction and Disclosure of Information
4.3 Communication and Authentication
5. Services
5.1 Incident Response
5.1.1. Incident Triage
5.1.2. Incident Coordination
5.1.3. Incident Resolution
5.2 Proactive Activities
6. Incident Reporting Forms
7. Disclaimers
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Expectations for Computer Security Incident Response 11 September 97
Appendix E: Example - 'filled-in' Template for a CSIRT
Below is an example of a filled-in template for a fictitious CSIRT
called XYZ-CSIRT. This text is for example purposes only, and does
not constitute endorsement by the working group or the IETF of any
particular set of procedures or policies. While CSIRTs are welcome
to use any or all of this text if they wish, such use is of course
not mandatory, or even appropriate in most cases.
CSIRT Description for XYZ-CERT
-----------------------------
1. About this document
1.1 Date of Last Update
This is version 1.01, published 1997/03/31.
1.2 Distribution List for Notifications
Notifications of updates are submitted to our mailing list
<xyz-cert-info@xyz-univ.ca>. Subscription requests for this
list should be sent to the Majordomo at
<xyz-cert-info-request@xyz-univ.ca>; the body of the message
should consist of the word "subscribe". Send the word "help"
instead if you don't know how to use a Majordomo list manager.
This mailing list is moderated.
1.3 Locations where this Document May Be Found
The current version of this CSIRT description document is
available from the XYZ-CERT WWW site; its URL is
http://www.xyz-univ.ca/xyz-cert/english/CSIRT-descr.txt
Une version francaise de ce document est igalement disponible:
http://www.xyz-univ.ca/xyz-cert/francais/CSIRT-descr.txt
Please make sure you are using the latest version.
1.4 Authenticating this Document
Both the English and French versions of this document have
been signed with the XYZ-CERT's PGP key. The signatures are
also on our Web site, under:
http://www.xyz-univ.ca/xyz-cert/english/CSIRT-descr.asc
http://www.xyz-univ.ca/xyz-cert/francais/CSIRT-descr.asc
2. Contact Information
2.1 Name of the Team
"XYZ-CERT": the XYZ University Computer Emergency Response
Team.
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2.2 Address
XYZ-CERT
XYZ University, Computing Services Department
12345 Rue Principale
UniversityTown, Quebec
Canada H0H 0H0
2.3 Time Zone
Canada/Eastern (GMT-0500, and GMT-0400 from April to October)
2.4 Telephone Number
+1 234 567 7890 (ask for the XYZ-CERT)
2.5 Facsimile Number
+1 234 567 7899 (this is *not* a secure fax)
2.6 Other Telecommunication
None available.
2.7 Electronic Mail Address
<xyz-cert@xyz-univ.ca> This is a mail alias that relays mail
to the human(s) on duty for the XYZ-CERT.
2.8 Public Keys and Other Encryption Information
The XYZ-CERT has a PGP key, whose KeyID is 12345678 and
whose fingerprint is
11 22 33 44 55 66 77 88 88 77 66 55 44 33 22 11.
The key and its signatures can be found at the usual large
public keyservers.
Because PGP is still a relatively new technology at XYZ
University, this key still has relatively few signatures;
efforts are underway to increase the number of links to this
key in the PGP "web of trust". In the meantime, since most
fellow universities in Quebec have at least one staff member
who knows the XYZ-CERT coordinator Zoe Doe, Zoe Doe has
signed the XYZ-CERT key, and will be happy to confirm its
fingerprint and that of her own key to those people who know
her, by telephone or in person.
2.9 Team Members
Zoe Doe of Computing Services is the XYZ-CERT coordinator.
Backup coordinators and other team members, along with their
areas of expertise and contact information, are listed in the
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Expectations for Computer Security Incident Response 11 September 97
XYZ-CERT web pages, at
http://www.xyz-univ.ca/xyz-cert/teamlist.html
Management, liaison and supervision are provided by Steve Tree,
Assistant Director (Technical Services), Computing Services.
2.10 Other Information
General information about the XYZ-CERT, as well as links to
various recommended security resources, can be found at
http://www.xyz-univ.ca/xyz-cert/index.html
2.11 Points of Customer Contact
The preferred method for contacting the XYZ-CERT is via
e-mail at <xyz-cert@xyz-univ.ca>; e-mail sent to this address
will "biff" the responsible human, or be automatically
forwarded to the appropriate backup person, immediately. If
you require urgent assistance, put "urgent" in your subject
line.
If it is not possible (or not advisable for security reasons)
to use e-mail, the XYZ-CERT can be reached by telephone during
regular office hours. Telephone messages are checked less
often than e-mail.
The XYZ-CERT's hours of operation are generally restricted to
regular business hours (09:00-17:00 Monday to Friday except
holidays).
If possible, when submitting your report, use the form
mentioned in section 6.
3. Charter
3.1 Mission Statement
The purpose of the XYZ-CERT is, first, to assist members of XYZ
University community in implementing proactive measures to
reduce the risks of computer security incidents, and second, to
assist XYZ community in responding to such incidents when they
occur.
3.2 Constituency
The XYZ-CERT's constituency is the XYZ University community,
as defined in the context of the "XYZ University Policy on
Computing Facilities". This policy is available at
http://www-compserv.xyz-univ.ca/policies/pcf.html
However, please note that, notwithtanding the above, XYZ-CERT
services will be provided for on-site systems only.
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3.3 Sponsorship and/or Affiliation
The XYZ-CERT is sponsored by the ACME Canadian Research
Network. It maintains affiliations with various University
CSIRTs throughout Canada and the USA on an as needed basis.
3.4 Authority
The XYZ-CERT operates under the auspices of, and with authority
delegated by, the Department of Computing Services of XYZ
University. For further information on the mandate and
authority of the Department of Computing Services, please
refer to the XYZ University "Policy on Computing Facilities&" in this document are to be interpreted as described in
BCP 14 [1] [7] when, and only when, they appear in all capitals, as
shown here. The key words indicate requirement levels for compliant
Mtrace2 implementations.
2.1. Definitions
Since Mtrace2 Queries and Requests flow in the opposite direction to
the data flow, we refer to "upstream" and "downstream" with respect
to data, unless explicitly specified.
Incoming Interface:
The interface on which data is expected to arrive from the
specified source and group.
Outgoing Interface:
This is one of the interfaces to which data from the source or RP
is expected to be transmitted for the specified source and group.
It is also the interface on which the Mtrace2 Request was
received.
Asaeda, et al. Standards Track [Page 7]
RFC 8487 Mtrace2 October 2018
Upstream router:
The router, connecting to the Incoming Interface of the current
router, which is responsible for forwarding data for the specified
source and group to the current router.
First-Hop Router (FHR):
The router that is directly connected to the source the Mtrace2
Query specifies.
Last-Hop Router (LHR):
A router that is directly connected to a receiver. It is also the
router that receives the Mtrace2 Query from an Mtrace2 client.
Group state:
The state a shared-tree protocol, such as Protocol Independent
Multicast - Sparse Mode (PIM-SM) [5], uses to choose the upstream
router towards the RP for the specified group. In this state,
source-specific state is not available for the corresponding group
address on the router.
Source-specific state:
The state that is used to choose the path towards the source for
the specified source and group.
ALL-[protocol]-ROUTERS group:
Link-local multicast address for multicast routers to communicate
with their adjacent routers that are running the same routing
protocol. For instance, the IPv4 'ALL-PIM-ROUTERS' group is
'224.0.0.13', and the IPv6 'ALL-PIM-ROUTERS' group is 'ff02::d'
[5].
3. Packet Formats
This section describes the details of the packet formats for Mtrace2
messages.
All Mtrace2 messages are encoded in the Type/Length/Value (TLV)
format (see Section 3.1). The first TLV of a message is a message
header TLV specifying the type of message and additional context
information required for processing of the message and for parsing of
subsequent TLVs in the message. Subsequent TLVs in a message,
referred to as Blocks, are appended after the header TLV to provide
additional information associated with the message. If an
implementation receives an unknown TLV Type for any TLV in a message,
it SHOULD ignore and silently discard the entire packet. If the
length of a TLV exceeds the available space in the containing packet,
the implementation MUST ignore and silently discard the TLV and any
remaining portion of the containing packet.
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RFC 8487 Mtrace2 October 2018
All Mtrace2 messages are UDP packets. For IPv4, Mtrace2
Query/Request/Reply messages MUST NOT be fragmented. Therefore,
Mtrace2 clients and LHRs/RPs MUST set the IP header do-not-fragment
(DF) bit for all Mtrace2 messages. For IPv6, the packet size for the
Mtrace2 messages MUST NOT exceed 1280 bytes, which is the smallest
Maximum Transmission Unit (MTU) for an IPv6 interface [8]. The
source port is uniquely selected by the local host operating system.
The destination port is the IANA-reserved Mtrace2 port number (see
Section 8). All Mtrace2 messages MUST have a valid UDP checksum.
Additionally, Mtrace2 supports both IPv4 and IPv6, but not when
mixed. For example, if an Mtrace2 Query or Request message arrives
as an IPv4 packet, all addresses specified in the Mtrace2 messages
MUST be IPv4 as well. The same rule applies to IPv6 Mtrace2
messages.
3.1. Mtrace2 TLV Format
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Value .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 8 bits
Describes the format of the Value field. For all the available
types, please see Section 3.2.
Length: 16 bits
Length of Type, Length, and Value fields in octets. Minimum
length required is 4 octets. The length MUST be a multiple of 4
octets. The maximum TLV length is not defined; however, the
entire Mtrace2 packet length MUST NOT exceed the available MTU.
Value: variable length
The format is based on the Type value. The length of the Value
field is the Length field minus 3. All reserved fields in the
Value field MUST be transmitted as zeros and ignored on receipt.
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RFC 8487 Mtrace2 October 2018
3.2. Defined TLVs
The following TLV Types are defined:
Code Type
==== ================================
0x00 Reserved
0x01 Mtrace2 Query
0x02 Mtrace2 Request
0x03 Mtrace2 Reply
0x04 Mtrace2 Standard Response Block
0x05 Mtrace2 Augmented Response Block
0x06 Mtrace2 Extended Query Block
Each Mtrace2 message MUST begin with either a Query, a Request, or a
Reply TLV. The first TLV determines the type of each Mtrace2
message. Following a Query TLV, there can be a sequence of optional
Extended Query Blocks. In the case of a Request or a Reply TLV, it
is then followed by a sequence of Standard Response Blocks, each from
a multicast router on the path towards the source or the RP. In the
case where more information is needed, a Standard Response Block can
be followed by one or multiple Augmented Response Blocks.
We will describe each message type in detail in the next few
sections.
3.2.1. Mtrace2 Query
An Mtrace2 Query is originated by an Mtrace2 client, which sends an
Mtrace2 Query message to the LHR. The LHR modifies only the Type
field of the Query TLV (to turn it into a "Request") before appending
a Standard Response Block and forwarding it upstream. The LHR and
intermediate routers handling the Mtrace2 message when tracing
upstream MUST NOT modify any other fields within the Query/Request
TLV. Additionally, intermediate routers handling the message after
the LHR has converted the Query into a Request MUST NOT modify the
Type field of the Request TLV. If the actual number of hops is not
known, an Mtrace2 client could send an initial Query message with a
large # Hops (e.g., 0xff), in order to try to trace the full path.
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RFC 8487 Mtrace2 October 2018
An Mtrace2 Query message is shown as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | # Hops |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Multicast Address |
| |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| |
| Source Address |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Mtrace2 Client Address |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Query ID | Client Port # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits
The Length field MUST be either 20 (i.e., 8 + 3 * 4 (IPv4
addresses)) or 56 (i.e., 8 + 3 * 16 (IPv6 addresses)); if the
length is 20, then IPv4 addresses MUST be assumed, and if the
length is 56, then IPv6 addresses MUST be assumed.
# Hops: 8 bits
This field specifies the maximum number of hops that the Mtrace2
client wants to trace. If there are some error conditions in the
middle of the path that prevent an Mtrace2 Reply from being
received by the client, the client MAY issue another Mtrace2 Query
with a lower number of hops until it receives a Reply.
Multicast Address: 32 bits or 128 bits
This field specifies an IPv4 or IPv6 address, which can be either:
m-1: a multicast group address to be traced or
m-2: all ones in case of IPv4 or the unspecified address (::) in
case of IPv6 if no group-specific information is desired.
Asaeda, et al. Standards Track [Page 11]
RFC 8487 Mtrace2 October 2018
Source Address: 32 bits or 128 bits
This field specifies an IPv4 or IPv6 address, which can be either:
s-1: a unicast address of the source to be traced or
s-2: all ones in case of IPv4 or the unspecified address (::) in
case of IPv6 if no source-specific information is desired.
For example, the client is tracing a (*,g) group state.
Note that it is invalid to have a source-group combination of
(s-2, m-2). If a router receives such combination in an Mtrace2
Query, it MUST silently discard the Query.
Mtrace2 Client Address: 32 bits or 128 bits
This field specifies the Mtrace2 client's IPv4 address or IPv6
global address. This address MUST be a valid unicast address;
therefore, it MUST NOT be all ones or an unspecified address. The
Mtrace2 Reply will be sent to this address.
Query ID: 16 bits
This field is used as a unique identifier for this Mtrace2 Query
so that duplicate or delayed Reply messages may be detected.
Client Port #: 16 bits
This field specifies the destination UDP port number for receiving
the Mtrace2 Reply packet.
3.2.2. Mtrace2 Request
The Mtrace2 Request TLV is exactly the same as an Mtrace2 Query
except for identifying the Type field of 0x02.
When an LHR receives an Mtrace2 Query message, it turns the Query
into a Request by changing the Type field of the Query from 0x01 to
0x02. The LHR then appends an Mtrace2 Standard Response Block (see
Section 3.2.4) of its own to the Request message before sending it
upstream. The upstream routers do the same without changing the Type
field until one of them is ready to send a Reply.
3.2.3. Mtrace2 Reply
The Mtrace2 Reply TLV is exactly the same as an Mtrace2 Query except
for identifying the Type field of 0x03.
When an FHR or an RP receives an Mtrace2 Request message that is
destined to itself, it appends an Mtrace2 Standard Response Block
(see Section 3.2.4) of its own to the Request message. Next, it
turns the Request message into a Reply by changing the Type field of
Asaeda, et al. Standards Track [Page 12]
RFC 8487 Mtrace2 October 2018
quot;,
available at
http://www-compserv.xyz-univ.ca/policies/pcf.html
The XYZ-CERT expects to work cooperatively with system
administrators and users at XYZ University, and, insofar as
possible, to avoid authoritarian relationships. However,
should circumstances warrant it, the XYZ-CERT will appeal to
Computing Services to exert its authority, direct or indirect,
as necessary. All members of the XYZ-CERT are members of the
CCSA (Committee of Computer Systems Administrators), and have
all of the powers and responsibilities assigned to Systems
Administrators by the Policy on Computing Facilities, or are
members of University management.
Members of the XYZ University community who wish to appeal the
actions of the XYZ-CERT should contact the Assistant Director
(Technical Services), Computing Services. If this recourse is
not satisfactory, the matter may be referred to the Director
of Computing Services (in the case of perceived
problems with existing policy), or to the XYZ University
Office of Rights and Responsibilities (in the case of perceived
errors in the application of existing policy).
4. Policies
4.1 Types of Incidents and Level of Support
The XYZ-CERT is authorized to address all types of computer
security incidents which occur, or threaten to occur, at
XYZ University.
The level of support given by XYZ-CERT will vary depending on
the type and severity of the incident or issue, the type of
constituent, the size of the user community affected, and the
XYZ-CERT's resources at the time, though in all cases some
response will be made within one working day. Resources will
be assigned according to the following priorities, listed in
decreasing order:
Brownlee, Guttman Internet Draft [Page 24]
Expectations for Computer Security Incident Response 11 September 97
- Threats to the physical safety of human beings.
- Root or system-level attacks on any Management Information
System, or any part of the backbone network infrastructure.
- Root or system-level attacks on any large public service
machine, either multi-user or dedicated-purpose.
- Compromise of restricted confidential service accounts or
software installations, in particular those used for MIS
applications containing confidential data, or those used
for system administration.
- Denial of service attacks on any of the above three items.
- Any of the above at other sites, originating from XYZ
University.
- Large-scale attacks of any kind, e.g. sniffing attacks,
IRC "social engineering" attacks, password cracking
attacks.
- Threats, harrassment, and other criminal offenses
involving individual user accounts.
- Compromise of individual user accounts on multi-user
systems.
- Compromise of desktop systems.
- Forgery and misrepresentation, and other security-related
violations of local rules and regulations, e.g. netnews
and e-mail forgery, unauthorized use of IRC bots.
- Denial of service on individual user accounts, e.g.
mailbombing.
Types of incidents other than those mentioned above will be
prioritized according to their apparent severity and extent.
Note that no direct support will be given to end users; they
are expected to contact their system administrator, network
administrator, or department head for assistance. The XYZ-CERT
will support the latter people.
While the XYZ-CERT understands that there exists great
variation in the level of system administrator expertise at XYZ
University, and while the XYZ-CERT will endeavor to present
information and assistance at a level appropriate to each
person, the XYZ-CERT cannot train system administrators on the
fly, and it cannot perform system maintenance on their behalf.
In most cases, the XYZ-CERT will provide pointers to the
information needed to implement appropriate measures.
The XYZ-CERT is committed to keeping the XYZ University system
administration community informed of potential vulnerabilities,
and where possible, will inform this community of such
vulnerabilities before they are actively exploited.
4.2 Co-operation, Interaction and Disclosure of Information
While there are legal and ethical restrictions on the flow of
information from XYZ-CERT, many of which are also outlined in
Brownlee, Guttman Internet Draft [Page 25]
Expectations for Computer Security Incident Response 11 September 97
the XYZ University Policy on Computing Facilities, and all of
which will be respected, the XYZ-CERT acknowledges its
indebtedness to, and declares its intention to contribute to,
the spirit of cooperation that created the Internet.
Therefore, while appropriate measures will be taken to protect
the identity of members of our constituency and members of
neighbouring sites where necessary, the XYZ-CERT will otherwise
share information freely when this will assist others in
resolving or preventing security incidents.
In the paragraphs below, "affected parties" refers to the
legitimate owners, operators, and users of the relevant
computing facilities. It does not refer to unauthorized
users, including otherwise authorized users making
unauthorized use of a facility; such intruders may have no
expectation of confidentiality from the XYZ-CERT. They may or
may not have legal rights to confidentiality; such rights will
of course be respected where they exist.
Information being considered for release will be classified as
follows:
- Private user information is information about particular
users, or in some cases, particular applications, which
must be considered confidential for legal, contractual,
and/or ethical reasons.
Private user information will be not be released in
identifiable form outside the XYZ-CERT, except as provided
for below. If the identity of the user is disguised, then
the information can be released freely (for example to show
a sample .cshrc file as modified by an intruder, or to
demonstrate a particular social engineering attack).
- Intruder information is similar to private user
information, but concerns intruders.
While intruder information, and in particular identifying
information, will not be released to the public (unless it
becomes a matter of public record, for example because
criminal charges have been laid), it will be exchanged
freely with system administrators and CSIRTs tracking an
incident.
- Private site information is technical information about
particular systems or sites.
It will not be released without the permission of the site
in question, except as provided for below.
- Vulnerability information is technical information about
vulnerabilities or attacks, including fixes and
Brownlee, Guttman Internet Draft [Page 26]
Expectations for Computer Security Incident Response 11 September 97
workarounds.
Vulnerability information will be released freely, though
every effort will be made to inform the relevant vendor
before the general public is informed.
- Embarrassing information includes the statement that an
incident has occurred, and information about its extent or
severity. Embarrassing information may concern a site or
a particular user or group of users.
Embarrassing information will not be released without the
permission of the site or users in question, except as
provided for below.
- Statistical information is embarrassing information with
the identifying information stripped off.
Statistical information will be released at the discretion
of the Computing Services Department.
- Contact information explains how to reach system
administrators and CSIRTs.
Contact information will be released freely, except where
the contact person or entity has requested that this not
be the case, or where XYZ-CERT has reason to believe that
the dissemination of this information would not be
appreciated.
Potential recipients of information from the XYZ-CERT will be
classified as follows:
- Because of the nature of their responsibilities and
consequent expectations of confidentiality, members of XYZ
University management are entitled to receive whatever
information is necessary to facilitate the handling of
computer security incidents which occur in their
jurisdictions.
- Members of the Office of Rights and Responsibilities are
entitled to receive whatever information they request
concerning a computer security incident or related matter
which has been referred to them for resolution. The same is
true for the XYZ Security Department, when its assistance in
an investigation has been enlisted, or when the investigation
has been instigated at its request.
- System administrators at XYZ University who are members of
the CCSA are also, by virtue of their responsibilities,
trusted with confidential information. However, unless such
people are also members of XYZ-CERT, they will be given only
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that confidential information which they must have in order
to assist with an investigation, or in order to secure their
own systems.
- Users at XYZ University are entitled to information which
pertains to the security of their own computer accounts,
even if this means revealing "intruder information", or
"embarrasssing information" about another user. For
example, if account aaaa is cracked and the intruder attacks
account bbbb, user bbbb is entitled to know that aaaa was
cracked, and how the attack on the bbbb account was
executed. User bbbb is also entitled, if she or he requests
it, to information about account aaaa which might enable
bbbb to investigate the attack. For example, if bbbb was
attacked by someone remotely connected to aaaa, bbbb should
be told the provenance of the connections to aaaa, even
though this information would ordinarily be considered
private to aaaa. Users at XYZ University are entitled to be
notified if their account is believed to have been
compromised.
- The XYZ University community will receive no restricted
information, except where the affected parties have given
permission for the information to be disseminated.
Statistical information may be made available to the general
XYZ community. There is no obligation on the part of the
XYZ-CERT to report incidents to the community, though it may
choose to do so; in particular, it is likely that the
XYZ-CERT will inform all affected parties of the ways in
which they were affected, or will encourage the affected site
to do so.
- The public at large will receive no restricted information.
In fact, no particular effort will be made to communicate
with the public at large, though the XYZ-CERT recognizes
that, for all intents and purposes, information made
available to the XYZ University community is in effect made
available to the community at large, and will tailor the
information in consequence.
- The computer security community will be treated the same way
the general public is treated. While members of XYZ-CERT may
participate in discussions within the computer security
community, such as newsgroups, mailing lists (including the
full-disclosure list "bugtraq"), and conferences, they will
treat such forums as though they were the public at large.
While technical issues (including vulnerabilities) may be
discussed to any level of detail, any examples taken from
XYZ-CERT experience will be disguised to avoid identifying
the affected parties.
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- The press will also be considered as part of the general
public. The XYZ-CERT will not interact directly with the
Press concerning computer security incidents, except to point
them toward information already released to the general
public. If necessary, information will be provided to the
XYZ University Public Relations Department, and to the
Customer Relations group of the Computing Services
Department. All incident-related queries will be referred to
these two bodies. The above does not affect the ability of
members of XYZ-CERT to grant interviews on general computer
security topics; in fact, they are encouraged to do to, as a
public service to the community.
- Other sites and CSIRTs, when they are partners in the
investigation of a computer security incident, will in some
cases be trusted with confidential information. This will
happen only if the foreign site's bona fide can be verified,
and the information transmitted will be limited to that which
is likely to be helpful in resolving the incident. Such
information sharing is most likely to happen in the case of
sites well known to XYZ-CERT (for example, several other
Quebec universities have informal but well-established
working relationships with XYZ University in such mattters).
For the purposes of resolving a security incident, otherwise
semi-private but relatively harmless user information such as
the provenance of connections to user accounts will not be
considered highly sensitive, and can be transmitted to a
foreign site without excessive precautions. "Intruder
information" will be transmitted freely to other system
administrators and CSIRTs. "Embarrassing information" can be
transmitted when there is reasonable assurance that it will
remain confidential, and when it is necessary to resolve an
incident.
- Vendors will be considered as foreign CSIRTs for most intents
and purposes. The XYZ-CERT wishes to encourage vendors of
all kinds of networking and computer equipment, software, and
services to improve the security of their products. In aid
of this, a vulnerability discovered in such a product will be
reported to its vendor, along with all technical details
needed to identify and fix the problem. Identifying details
will not be given to the vendor without the permission of the
affected parties.
- Law enforcement officers will receive full cooperation from
the XYZ-CERT, including any information they require to
pursue an investigation, in accordance with the Policy on
Computing Facilities.
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4.3 Communication and Authentication
In view of the types of information that the XYZ-CERT will
likely be dealing with, telephones will be considered
sufficiently secure to be used even unencrypted. Unencrypted
e-mail will not be considered particularly secure, but will be
sufficient for the transmission of low-sensitivity data. If
it is necessary to send highly sensitive data by e-mail, PGP
will be used. Network file transfers will be considered to
be similar to e-mail for these purposes: sensitive data should
be encrypted for transmission.
Where it is necessary to establish trust, for example before
relying on information given to the XYZ-CERT, or before
disclosing confidential information, the identity and bona
fide of the other party will be ascertained to a reasonable
degree of trust. Within XYZ University, and with known
neighbor sites, referrals from known trusted people will
suffice to identify someone. Otherwise, appropriate methods
will be used, such as a search of FIRST members, the use of
WHOIS and other Internet registration information, etc, along
with telephone call-back or e-mail mail-back to ensure that
the party is not an impostor. Incoming e-mail whose data must
be trusted will be checked with the originator personally, or
by means of digital signatures (PGP in particular is
supported).
5. Services
5.1 Incident Response
XYZ-CERT will assist system administrators in handling the
technical and organizational aspects of incidents. In
particular, it will provide assistance or advice with respect
to the following aspects of incident management:
5.1.1 Incident Triage
- Investigating whether indeed an incident occured.
- Determining the extent of the incident.
5.1.2 Incident Coordination
- Determining the initial cause of the incident
(vulnerability exploited).
- Facilitating contact with other sites which may be
involved.
- Facilitating contact with XYZ University Security and/or
appropriate law enforcement officials, if necessary.
- Making reports to other CSIRTs.
- Composing announcements to users, if applicable.
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5.1.3 Incident Resolution
- Removing the vulnerability.
- Securing the system from the effects of the incident.
- Evaluating whether certain actions are likely to reap
results in proportion to their cost and risk, in
particular those actions aimed at an eventual prosecution
or disciplinary action: collection of evidence after the
fact, observation of an incident in progress, setting
traps for intruders, etc.
- Collecting evidence where criminal prosecution, or
University disciplinary action, is contemplated.
In addition, XYZ-CERT will collect statistics concerning
incidents which occur within or involve the XYZ University
community, and will notify the community as necessary to
assist it in protecting against known attacks.
To make use of XYZ-CERT's incident response services, please
send e-mail as per section 2.11 above. Please remember that
the amount of assistance available will vary according to
the parameters described in section 4.1.
5.2 Proactive Activities
The XYZ-CERT coordinates and maintains the following
services to the extent possible depending on its resources:
- Information services
- List of departmental security contacts, administrative
and technical. These lists will be available to the
general public, via commonly-available channels such as
the World Wide Web and/or the Domain Name Service.
- Mailing lists to inform security contacts of new
information relevant to their computing environments.
These lists will be available only to XYZ University
system administrators.
- Repository of vendor-provided and other security-related
patches for various operating systems. This repository
will be available to the general public wherever
license restrictions allow it, and will be provided via
commonly-available channels such as the World Wide Web
and/or ftp.
- Repository of security tools and documentation for
use by sysadmins. Where possible, precompiled
ready-to-install versions will be supplied. These will
be supplied to the general public via www or ftp as
above.
- "Clipping" service for various existing resources, such
as major mailing lists and newsgroups. The resulting
clippings will be made available either on the
restricted mailing list or on the web site, depending
on their sensitivity and urgency.
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- Training services
- Members of the XYZ-CERT will give periodic seminars on
computer security related topics; these seminars will
be open to XYZ University system administrators.
- Auditing services
- Central file integrity checking service for Unix
machines, and for any other platforms capable of
running "tripwire".
- Security level assignments; machines and subnetworks
at XYZ University will be audited and assigned a
security level. This security level information will be
available to the XYZ University community, to facilitate
the setting of appropriate access privileges. However,
details of the security analyses will be confidential,
and available only to the concerned parties.
- Archiving services
- Central logging service for machines capable of
Unix-style remote logging. Incoming log entries will
be watched by an automated log analysis program, and
events or trends indicative of a potential security
problem will be reported to the affected system
administrators.
- Records of security incidents handled will be kept.
While the records will remain confidential, periodic
statistical reports will be made available to the XYZ
University community.
Detailed descriptions of the above services, along with
instructions for joining mailing lists, downloading
information, or participating in certain services such as the
central logging and file integrity checking services, are
available on the XYZ-CERT web site, as per section 2.10
above.
6. Incident Reporting Forms
There are no local forms developed yet for reporting incidents
to XYZ-CERT. If possible, please make use of the Incident
Reporting Form of the CERT Coordination Center (Pittsburgh,
PA). The current version is available from:
ftp://info.cert.org/incident_reporting_form
7. Disclaimers
While every precaution will be taken in the preparation of
information, notifications and alerts, XYZ-CERT assumes no
responsibility for errors or omissions, or for damages
resulting from the use of the information contained within.
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4 Acknowlegements
The editors gratefully acknowledge the contributed material and
editorial scrutiny of Anne Bennett. Thanks also to Don Stikvoort
for assistance reworking the description of Incident Response Team
services.
5 References
[RFC 1244] P. Holbrooks, J. Reynolds / Site Security Handbook. -
July 23, 1991. - 101 pages. - FYI 8.
[RFC 1983] G. Malkin / Internet Users' Glossary. -
August 16, 1996. - 62 pages. - FYI 18.
6 Security Considerations
This document discusses the operation of Computer Security
Incident Response Teams, and the teams' interactions with their
constituencies and with other organizations. It is, therefore,
not directly concerned with the security of protocols, applications,
or network systems themselves. It is not even concerned with
particular responses and reactions to security incidents, but only
with the appropriate description of the responses provided by
CSIRTs.
Nonetheless, it is vital that the CSIRTs themselves operate securely,
which means that they must establish secure communication channels
with other teams, and with members of their constituency. They must
also secure their own systems and infrastructure, to protect the
interests of their constituency and to maintain the confidentiality
of the identity of victims and reporters of security incidents.
7 Authors' Addresses
Nevil Brownlee Erik Guttman
ITSS Technology Development Sun Microsystems, Inc.
The University of Auckland Bahnstr. 2
74915 Waibstadt Germany
Phone: +64 9 373 7599 x8941
E-mail: n.brownlee@auckland.ac.nz Phone: +49 7263 911484
E-Mail: Erik.Guttman@sun.com
This document expires March 11, 1998.
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