Asterisk Project Security Advisory – An attacker sending a valid RTP comfort noise payload containing a data length of 24 bytes or greater can remotely crash Asterisk.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/83317/AST-2009-010.txt
Source: https://packetstormsecurity.com/files/83317/Asterisk-Project-Security-Advisory-AST-2009-010.html