Some vulnerabilities have been reported in Asterisk, which potentially can be exploited by malicious people to cause a DoS (Denial of Service) or compromise a vulnerable system.

1) Two boundary errors exist in the T.38 SDP parser of the SIP channel when processing the "T38FaxRateManagement" or "T38FaxUdpEC" SDP parameters within the "process_sdp()" function in chan_sip.c. This can be exploited to cause stack-based buffer overflows by sending a specially crafted SIP packet with overly long SDP parameters.

Successful exploitation requires that the "t38_udptl" configuration option is set to "yes".

The vulnerabilities is reported in the 1.4.x branch prior to version 1.4.3.

2) A NULL pointer dereference error exists within the authentication mechanism of the Asterisk Remote Management Interface, which can be exploited to crash the service.

Successful exploitation requires that the Management Interface is enabled and a user without a password is configured in the manager.conf file.

The vulnerability is reported in the 1.2.x branch before 1.2.18 and the 1.4.x branch before 1.4.3.

Solution
Update to version 1.4.3.

Provided and/or discovered by
1) Barrie Dempster, NGS Software
2) Reported by Digium Technical Support

Changelog
Further details available to Secunia VIM customers

Original Advisory
http://lists.grok.org.uk/pipermail/full-disclosure/2007-April/053969.html
http://lists.grok.org.uk/pipermail/full-disclosure/2007-April/053968.html

Deep Links
Links available to Secunia VIM customers