Asterisk is an open source telephony engine and toolkit. Multiple vulnerabilities have been found in Asterisk allowing for Denial of Service and username disclosure.
Remote unauthenticated attackers could send specially crafted data to Asterisk, possibly resulting in a Denial of Service via a daemon crash, call-number exhaustion, CPU or traffic consumption. Remote unauthenticated attackers could furthermore enumerate valid usernames to facilitate brute force login attempts.
Vulnerable Systems:
* Asterisk versions prior to 1.2.32
Immune Systems:
* Asterisk version 1.2.32 and newer
Multiple vulnerabilities have been discovered in the IAX2 channel driver when performing the 3-way handshake (CVE-2008-1897), when handling a large number of POKE requests (CVE-2008-3263), when handling authentication attempts (CVE-2008-5558) and when handling firmware download (FWDOWNL) requests (CVE-2008-3264). Asterisk does also not correctly handle SIP INVITE messages that lack a "From" header (CVE-2008-2119), and responds differently to a failed login attempt depending on whether the user account exists (CVE-2008-3903, CVE-2009-0041).
