Asterisk Project Security Advisory – Multiple problems have been identified in the Asterisk SIP channel driver (chan_sip) when handling response packets from other SIP endpoints.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/56223/ASA-2007-011.txt
Source: https://packetstormsecurity.com/files/56223/ASA-2007-011.txt.html