Internet DRAFT - draft-tsitkov-audit
draft-tsitkov-audit
Network Working Group Zh. Tsitkov, Ed.
Internet-Draft MIT
Intended status: Informational October 14, 2014
Expires: April 17, 2015
Audit in OAuth 2.0
draft-tsitkov-audit-00
Abstract
This specification is an effort to provide guidelines for
implementing the Audit functionality for OAuth 2.0 enabled
environments. The data of interest for the OAuth 2.0 audit includes
permissions, scopes, policies and other authorization and
authentication related information. It can be used by user agents
and authorization services for fast violation response, credential
revocation, or by government agencies and various institutions for
forensic analysis.
Status of This Memo
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This Internet-Draft will expire on April 17, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 3
3. Audit ID . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Audit log parameters . . . . . . . . . . . . . . . . . . . . 4
5. Event selection . . . . . . . . . . . . . . . . . . . . . . . 5
6. Audit vs privacy . . . . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
9. Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
10. Normative References . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
This specification is an effort to provide guidelines for
implementing the Audit functionality for OAuth 2.0 [OAuth2] enabled
environments. The data of interest for the OAuth 2.0 audit includes
permissions, scopes, policies and other authorization and
authentication related information. It can be used by user agents
and authorization services for fast violation response, credential
revocation, or by government agencies and various institutions for
forensic analysis, and similar purposes.
The intention of this specification is:
o to address the quality of the content of audit logs. This is done
by identifying the mandatory, recommended and optional auditable
information from the OAuth 2.0 perspective;
o to improve audit log processing. This is achieved by introducing
an audit identifier that simplifies log querying;
o to encourage all OAuth 2.0 participants to store and protect
information that is useful for the audit.
The goal of this proposal is to provide a high quality feed to
various audit processing facilities. Identifying mechanisms of how
the logs are processed is outside the scope of this document. It can
be done dynamically, and, for example, trigger that tokens to be
revoked. It can be done by resource owner's Audit Agent. It can be
done off-line when audit analysis is performed.
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2. Notational Conventions
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this
document are to be interpreted as described in [RFC2119].
Unless otherwise noted, all the protocol properties and values are
case sensitive.
3. Audit ID
To optimize audit log handling this document introduces an Audit ID
(audit_id) an identifier with the following properties:
o It is unique and stays unchanged for a given OAuth 2.0 end-to-end
communication;
o It is generated as part of OAuth 2.0 processing;
o It is protected against data tampering;
o It is available to all OAuth 2.0 participants to be recorded for
their audit needs;
o It can be passed to downstream modules.
The audit_id becomes useful when, for example, one of the OAuth 2.0
participants (most likely resource server or authorization server)
suspects some malicious activity. It can then request the other
participants to provide information from their audit logs that
corresponds to the particular audit_id and, based on the acquired
information, perform further analysis of the suspected attack.
Alternatively, suspecting party can issue warning to the other
participants about the suspicious activity associated with the
particular audit_id. In addition, in more static use-case, such as
forensic analysis, the audit identifier makes it possible and simple
to find out who was responsible for the violation, whether it was due
to the wrongful resource registration, misinterpreting the policies,
etc.
The audit identifier can be an alphanumeric string, or a JSON
structure. It can be randomly generated, or constructed out of some
unique parameters, such as components of the tokens, session ids,
timestamps.
The uniqueness of the audit_id is important especially in the cases
when audit logs are processed dynamically. Since randomizers on
Clients or resource server's (RS) are commonly weaker and less
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collision-resistant when compared to authorization server's (AS)
randomizers, in most environments, it should be the responsibility of
AS to generate a high quality "strong" audit id. However, it should
be allowed for the client or resource server to have their own audit
id's for internal bookkeeping. These identifiers can be passed to
the authorization server as part of the initial request and AS should
include it in the reply messages together with the "strong" AS-
selected audit id.
Authorization server may adopt any audit identifier coming from the
outside of AS as a "strong" audit ID if it believes that it is a high
quality identifier.
It is desirable for resource server, client and authorization server
to record audit related information for all communications, at least
for the mandatory set of parameters. It makes analysis of audit
trails more effective.
The audit ID can be passed to the downstream modules, such as OIDC
identity provider. The latter can use it for its own audit needs.
4. Audit log parameters
It is considered a good practice to keep the audit log concise.
Overloading logs with unnecessary information comes with the burden
of extra storage allocation and protection, and less effective
information processing (both time-wise and resource-wise).
The following are the recommended parameters that, when applicable,
should be included in the OAuth 2.0 audit logs for AS, RS and client.
All security sensitive information should be stripped and not logged.
The implementers have the opportunity to customize audit logs by
extending auditable parameters and events.
audit_id
A non-modifiable identifier that is used to track all
participants on all stages of the OAuth 2.0 communication;
event_type
A type of event. For example, "permissions problem";
event_category
Type of action performed when audit is generated. For example,
"resource server processing";
timestamp
A timestamp when event occurred;
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event_outcome
Indicates whether the event is reported on success or failure;
endpoint_uri
Endpoint URI;
source
Code specifying the type of source where event originated;
permissions
Requested, granted permissions including resource id, lifetime,
scopes, and other access attributes;
token_status
Full token status, including validity periods, corresponding
refresh tokens, etc
policies
Policies.
The content of the audit logs can be configurable. If, for example,
the performance or storage are a concern, the administrator may
choose to log only basic mandatory information. However, if this is
not the case, or under violation alert, more detailed audit
information may be useful. In this case the administrator may switch
the audit configuration from the basic level to the detailed. There
should be well defined mandatory set of parameters.
5. Event selection
In general, all AS-RS , Client-RS, Client-AS interactions, successful
or not, should be recorded in the audit log files. This includes
permission requests, token issuance, token introspection, etc.
6. Audit vs privacy
Privacy and auditing are closely related. As it has been discussed
in [Privacy-Considerations], audit trail can help to identify the
misuse of information, such as unauthorized secondary use of data.
On the other hand, stored audit logs may be compromised, data can be
collected and analyzed. To address the privacy risks one should make
sure that the audit system is simple, transparent, and unambiguous.
Generally, audit designers should minimize the exposure of privacy
related information in the logs. Also, it should always be clear, if
the audit logs are jeopardized, what privacy related information has
leaked.
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One should notice, that introducing audit_id into audit log in OAuth
2.0 enabled environments does not add any privacy related concerns.
7. IANA Considerations
This document makes no request of IANA.
8. Acknowledgments
TBD
9. Issues
10. Normative References
[OAuth2] Hardt, D., "The OAuth 2.0 Authorization Framework",
October 2012, <http://tools.ietf.org/html/rfc6749>.
[Privacy-Considerations]
Cooper, A., "Privacy Considerations for Internet
Protocols", July 2013,
<http://tools.ietf.org/html/rfc6973>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Author's Address
Zhanna Tsitkov (editor)
MIT
Email: tsitkova@mit.edu
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