Secunia

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

1) A boundary error exists in the Asterisk STUN implementation, which can be exploited to cause the application to crash via specially crafted RTP packets.

Successful exploitation requires that the chan_sip, chan_gtalk, chan_jingle, chan_h323, chan_mgcp, or chan_skinny is enabled.

The vulnerability is reported in the following products:
Asterisk Open Source 1.4.x prior to version 1.4.8
AsteriskNOW pre-release prior to version beta7
Asterisk Appliance Developer Kit prior to version 0.5.0
s800i 1.0.x prior to version 1.0.2.

2) A boundary error exists in the Asterisk Skinny channel driver (chan_skinny), which can be exploited to cause the application to crash via packets that contain a size field smaller than the actual size of the packet.

Successful exploitation requires that chan_skinny is enabled.

3) A NULL-pointer dereference error exists in the Asterisk IAX2 channel driver (chan_iax2), which can be exploited to cause a DoS via specially crafted LGRQ and LAGRP frames.

Successful exploitation requires that chan_iax is enabled.

4) A boundary error exists in the Asterisk IAX2 channel driver (chan_iax2) within the handling of RTP frames. This can be exploited to cause a stack-based buffer overflow by sending large data payloads (more than 4096 bytes) in a voice or video frame.

Successful exploitation of this vulnerability allows execution of arbitrary code, but requires that the system is configured to connect channels that use RTP and IAX channels.

Vulnerabilities #2, #3, and #4 are reported in the following products:
Asterisk Open Source 1.0.x
Asterisk Open Source 1.2.x prior to version 1.2.22
Asterisk Open Source 1.4.x prior to version 1.4.8
AsteriskNOW pre-release prior to version beta7
Asterisk Business Edition A.x.x
Asterisk Business Edition B.x.x prior to version B.2.2.1
Asterisk Appliance Developer Kit prior to version 0.5.0
s800i 1.0.x prior to version 1.0.2.

Solution
Asterisk Open Source 1.2.x:
Further details available in Customer Area

Provided and/or discovered by
The vendor credits:
1) and 2) Will Drewry, Google Security Team
3) Chris Clark and Zane Lackey, iSEC Partners
4) Russel Bryant

Original Advisory
1) http://ftp.digium.com/pub/asa/ASA-2007-017.pdf
2) http://ftp.digium.com/pub/asa/ASA-2007-016.pdf
3) http://ftp.digium.com/pub/asa/ASA-2007-015.pdf
4) http://ftp.digium.com/pub/asa/ASA-2007-014.pdf

Deep Links
Links available in Customer Area