Product

Asterisk

Summary

Remote Crash Vulnerability in SIP channel driver

Nature of Advisory

Remote attacker can crash an Asterisk server

Susceptibility

Remote Unauthenticated Sessions

Severity

Critical

Exploits Known

Yes

Reported On

06/15/2011

Reported By

Paul Belanger pabelanger@digium.com

Posted On

06/20/2011

Last Updated On

June 16, 2011

Advisory Contact

Kinsey Moore kmoore@digium.com

CVE Name

CVE-2011-2529

 

Description

If a remote user sends a SIP packet containing a null, Asterisk assumes available data extends past the null to the end of the packet when the buffer is actually truncated when copied.  This causes SIP header parsing to modify data past the end of the buffer altering unrelated memory structures.  This vulnerability does not affect TCP/TLS connections.

 

Resolution

Asterisk now uses the correct length when dealing with SIP packets containing nulls.  Available workarounds are to disable chan_sip or to upgrade.

 

Affected Versions

Product

Release Series

 

Asterisk Open Source

1.6.0.x

All

Asterisk Open Source

1.6.1.x

All

Asterisk Open Source

1.6.2.x

All

Asterisk Open Source

1.8.x

All

 

Corrected In

Product

Release

Asterisk Open Source 1.6.2.x

1.6.2.18.1

Asterisk Open Source 1.8.x

1.8.4.3

 

Patches

URL

Branch

Http://downloads.asterisk.org/pub/security/AST-2011-008.diff

1.6.2, 1.8

 

Asterisk Project Security Advisories are posted at http://www.asterisk.org/security

This document may be superseded by later versions; if so, the latest version will be posted at http://downloads.digium.com/pub/security/AST-2011-008.pdf and http://downloads.digium.com/pub/security/AST-2011-008.html

 

Revision History

Date

Editor

Revisions Made

06/20/2011

Kinsey Moore

Initial Release