Asterisk is an open source implementation of a telephone private branch exchange (PBX).
The MU Security Research Team discovered that Asterisk contains a NULL-pointer dereferencing error in the SIP channel when handling request messages.
A remote attacker could cause an Asterisk server listening for SIP messages to crash by sending a specially crafted SIP request message.
There is no known workaround at this time.
All Asterisk users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose net-misc/asterisk
Note: Asterisk 1.0.x is no longer supported upstream so users should consider upgrading to Asterisk 1.2.x.