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atheme.org Security Advisory ASA-2012-03-01: Improper cleanup of CertFP entries may result in undefined behaviour
From: William Pitcock <nenolod () dereferenced org>
Date: Wed, 21 Mar 2012 13:55:23 -0500
atheme.org Security Advisory
Original release: March 20, 2012.
Last update: March 20, 2012.
Copyright (c) 2012 atheme.org and it's contributors.
All rights reserved.
Distribution of this document in full, or in part is allowed,
provided that it remains in unmodified form and the above
copyright notice and this permission notice remain unchanged.
Topic: Improper cleanup of CertFP entries may result in undefined
behaviour (privilege escalation or crash).
Versions affected: 5.2.0 - 5.2.6, 6.0.0 - 6.0.9, 7.0.0-alpha1 - 7.0.0-beta1
CVSSv2 vector: AV:N/AC:M/Au:M/C:C/I:P/A:C/E:F/RL:O/RC:C
CVSSv2 base score: 7.5
Access vector: network
Access complexity: medium
Authentication requirement: multiple instances
Confidentiality impact: complete
Integrity impact: partial
Availability impact: complete
CVSSv2 temporal score: 6.2
Exploitability: functional exploit exists
Remediation level: official fix
Report confidence: confirmed
Improper cleanup of CertFP entries may result in undefined behaviour for
an IRC system using Atheme IRC Services as an IRC services implementation.
If an account is expired or dropped, CertFP entries will linger, occasionally
pointing to an unallocated object (which triggers an exceptional condition)
or another account object. Thusly, if an attacker creates an account and then
registers their CertFP fingerprint with that account and deletes it, they may
be able to gain access to another account in the future without that account
being aware of it.
Such a condition can also cause inconsistencies in the object store when
marshalled to disk, resulting in an exceptional condition on demarshalling,
such as when services is restarted.
This vulnerability was introduced when CertFP support was added to Atheme
A denial of service against an IRC network's services daemon can have
devastating effects as a typical IRC network is dependent on the
availability of services for directory, nickname and channel ACL
This vulnerability was discovered by "Aaron M. D. Jones" and was reported
to us by him. The bug report is at: http://jira.atheme.org/browse/SRV-166
Upgrading to the latest release for the branch you are using is strongly
A patch release for all currently maintained versions of Atheme IRC
Services was released on the same day, March 20th.
If your current version of Atheme is maintained, patch releases are
available from the Atheme website at http://www.atheme.net/. These
versions are Atheme 5.2.7, Atheme 6.0.10 and Atheme 7.0.0-beta2.
The SHA256 checksums for these versions are:
This bug does not exist in any unmaintained version of Atheme as far
as we are aware.
The account destructor did not call mycertfp_delete() on the CertFP entries
associated with an account object. As a result, the certfp entries linger.
To exploit, register an account with your CertFP entry and then delete it.
Then reconnect to the network after a couple of new accounts are registered.
You may be authenticated to one of those new accounts, or services will crash.
For further information about this security advisory, please contact
the Atheme developers at irc.atheme.org #atheme.
For more information about atheme.org, please visit the following resources:
- IRC: irc.atheme.org #atheme-project
- Web: http://www.atheme.org/
- atheme.org Security Advisory ASA-2012-03-01: Improper cleanup of CertFP entries may result in undefined behaviour William Pitcock (Mar 22)