Secunia Security Advisory – Gentoo has issued an update for asterisk. This fixes multiple vulnerabilities, which can be exploited by malicious people to determine valid user names or cause a DoS (Denial of Service).
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/90314/sa40039.txt
Source: https://packetstormsecurity.com/files/90314/Secunia-Security-Advisory-40039.html