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Asterisk: Multiple vulnerabilities


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200610-15 / asterisk
Release Date October 30, 2006
Latest Revision January 30, 2007: 02
Impact high
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
net-misc/asterisk < 1.2.13, < 1.0.12 >= 1.2.13, revision >= 1.0.12 All supported architectures

Related bugreports: #144941, #151881


Asterisk is vulnerable to the remote execution of arbitrary code or a Denial of Service.

2.  Impact Information


Asterisk is an open source implementation of a telephone private branch exchange (PBX).


Asterisk contains buffer overflows in channels/chan_mgcp.c from the MGCP driver and in channels/chan_skinny.c from the Skinny channel driver for Cisco SCCP phones. It also dangerously handles client-controlled variables to determine filenames in the Record() function. Finally, the SIP channel driver in channels/chan_sip.c could use more resources than necessary under unspecified circumstances.


A remote attacker could execute arbitrary code by sending a crafted audit endpoint (AUEP) response, by sending an overly large Skinny packet even before authentication, or by making use of format strings specifiers through the client-controlled variables. An attacker could also cause a Denial of Service by resource consumption through the SIP channel driver.

3.  Resolution Information


There is no known workaround for the format strings vulnerability at this time. You can comment the lines in /etc/asterisk/mgcp.conf, /etc/asterisk/skinny.conf and /etc/asterisk/sip.conf to deactivate the three vulnerable channel drivers. Please note that the MGCP channel driver is disabled by default.


All Asterisk users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/asterisk-1.2.13"

4.  References


Page updated October 30, 2006

Summary: This is a Gentoo Linux Security Advisory

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