A vulnerability has been reported in Nortel IP Softphone 2050, which can be exploited by malicious people to cause a DoS (Denial of Service) and potentially to compromise a vulnerable system.

The vulnerability is caused due to boundary errors when processing invalid packets sent to the RTCP port. This can be exploited to cause a buffer overflow and crash the application via specially crafted packets.

Successful exploitation may allow execution of arbitrary code.

Solution
Update to release R2.2 Upgrade Version 264 (see vendor advisory for further details).

Provided and/or discovered by
Daniel Stirnimann and Cyrill Brunschwiler, Compass Security Network Computing AG

Changelog
Further details available to Secunia VIM customers

Original Advisory
Nortel:
http://support.nortel.com/go/main.jsp?cscat=BLTNDETAIL&id=696882

Compass Security Network Computing AG:
http://www.csnc.ch/static/advisory/csnc/nortel_UNIStim_IP_softphone_buffer-overflow_v1.0.txt

Deep Links
Links available to Secunia VIM customers