Cisco Unified IP Phone 7960G and 7940G (SIP) RTP Header Vulnerability

[Laurent Butti <laurent.butti@xxxxxxxxxxxxxxxxxx>]

Title:
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* Cisco Unified IP Phone 7960G and 7940G (SIP) RTP Header Vulnerability

Summary:
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* The Cisco Unified IP Phone 7960G and 7940G (SIP) do not correctly
parse some malformed RTP headers leading to a deterministic denial of
service

Assigned CVE:
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* CVE-2008-4444

Details:
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* SIP protocol is used to set up calls between phones. Once the call is
established, the media content is carried by the RTP protocol. A remote
attacker could send a specially crafted RTP packet against a Cisco SIP
phone in such a way as to cause the phone to reboot.

Attack Impact:
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* Denial-of-service (reboot or hang-up) and possibly remote arbitrary
code execution

Attack Vector:
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* Have the possibility to setup a call to the targeted phone and carry
RTP frame to the vulnerable device
* Have access to the VoIP network while a call is established and inject
RTP frames

Timeline:
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* 2008-06-13 - Vulnerability reported to Cisco
* 2008-06-16 - Full details sent to Cisco
* 2008-10-21 - Cisco released a patched firmware
* 2009-01-14 - Release of this security advisory

Affected Products:
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* Cisco Unified IP Phone 7960G and 7940G (SIP) with P0S3-08-9-00
firmware. Cisco released a patched firmware on October 21, 2008 which is
described in the bug identifier CSCsu22285 (Cisco Unified IP Phone 7960G
and 7940G (SIP) Release Notes for Firmware Release 8.10).

Credits:
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* This vulnerability was discovered by Gabriel Campana and Laurent Butti
from France Telecom / Orange