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TITLE:
Asterisk IAX2 Call Number Exhaustion Denial of Service

SECUNIA ADVISORY ID:
SA36593

VERIFY ADVISORY:
http://secunia.com/advisories/36593/

DESCRIPTION:
A vulnerability has been reported in Asterisk, which can be exploited
by malicious people to cause a DoS (Denial of Service).

The vulnerability is caused due to the call number field in a
messages being handled as a fixed size 15 bit field. This can be
exploited to exhaust all available call numbers via a large number of
messages and prevent the handling of further sessions.

The vulnerability is reported in the following products and
versions:
* Asterisk Open Source 1.2.x all versions
* Asterisk Open Source 1.4.x all versions
* Asterisk Open Source 1.6.x all versions
* Asterisk Business Edition B.x.x all versions
* Asterisk Business Edition C.x.x all versions
* s800i (Asterisk Appliance) 1.3.x all versions

SOLUTION:
Update to the latest versions or apply patches, and consult the users
guide section of the IAX2 Security document.

Asterisk Open Source 1.2.x:  
Update to version 1.2.35 or apply the patch.
http://downloads.asterisk.org/pub/security/AST-2009-006-1.2.diff.txt

Asterisk Open Source 1.4.x:
Update to version 1.4.26.2 or apply the patch.
http://downloads.asterisk.org/pub/security/AST-2009-006-1.4.diff.txt

Asterisk Open Source 1.6.x:
Update to version 1.6.0.15 or 1.6.1.6, or apply the patch.
http://downloads.asterisk.org/pub/security/AST-2009-006-1.6.0.diff.txt
http://downloads.asterisk.org/pub/security/AST-2009-006-1.6.1.diff.txt

Asterisk Business Edition B.x.x:
Update to version B.2.5.10.

Asterisk Business Edition C.x.x:
Update to version C.2.4.3 or C.3.1.1.

S800i (Asterisk Appliance):
Update to version 1.3.0.3.

PROVIDED AND/OR DISCOVERED BY:
The vendor credits:
* Noam Rathaus
* Blake Cornell

ORIGINAL ADVISORY:
http://downloads.asterisk.org/pub/security/AST-2009-006.html

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About:
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