| Heap Corruption in Gaim-Encryption Plugin
Author : Rapid 7 Security Advisories <firstname.lastname@example.org>
Rapid7, Inc. Security Advisory
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Rapid7 Advisory R7-0013
Heap Corruption in Gaim-Encryption Plugin
Published: April 11, 2003
Bugtraq ID: 7182
1. Affected system(s):
o gaim-encryption 1.15 and earlier
o gaim-encryption 1.16 and later
GAIM is a multi-protocol instant messaging client that is
compatible with AIM, ICQ, MSN Messenger, Jabber, and other
protocols. The Gaim-Encryption plugin provides transparent
message encryption between two users.
The Gaim-Encryption plugin does insufficient validation on the
message length parameter supplied by a remote user. This allows
an arbitrary heap location to be overwritten with a zero byte
and will also cause an unbounded read into the heap.
The most obvious impact of this vulnerability would be a denial
of service to the GAIM client. While this vulnerability is not
likely to be exploitable, exploitation cannot be ruled out.
Please note that Gaim-Encryption is not part of GAIM and is not
developed by GAIM.
3. Vendor status and information
William Tompkins <bill AT icarion DOT com>
The author was notified and a fixed version was released on
March 16th, 2003.
Upgrade to version 1.16 of the Gaim-Encryption plugin. Note that
while a patched version of 1.15 was released, some versions of
1.15 may still be vulnerable.
5. Detailed analysis
The decrypt_msg function is responsible for decrypting encrypted
GAIM messages. It reads the message length from a user-supplied
header using sscanf. While some bounds checking is performed, a
negative length is not properly handled. This causes the NUL
termination of the message string to place a zero byte in an
arbitrary location in memory rather than at the end of the string
where it belongs.
6. Contact Information
Rapid7 Security Advisories
Phone: +1 (212) 558-8700
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