The Asterisk PBX is susceptible to a remote denial of service vulnerability via a specially crafted INVITE message. Affected versions include 1.2.14, 1.2.15, 1.2.16, 1.4.1, and possibly earlier versions.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/55252/asterisk-dos.txt
Source: https://packetstormsecurity.com/files/55252/asterisk-dos.txt.html