Description: Sipera VIPER Lab has reported two vulnerabilities in Nortel Multimedia Communication Server (MCS) 5100, which can be exploited by malicious people to cause a DoS (Denial of Service).
The vulnerabilities are caused due to errors in the SIP header parsing module of the MCS PC Client and can be exploited to crash the application or cause a buffer overflow via a specially crafted SIP message containing a malformed header.
Successful exploitation may allow execution of arbitrary code.
The vulnerabilities are reported in release 4.1 version 3.5.208[20051015]. Other versions may also be affected.
Solution: Update to the latest versions:
MCS 5100 Release 3.5 MR 3.5.7 (Client Version 5.0.133(20061113))
MCS 5100 Release 4.0 MR 4.0.24 (Client Version 5.0.231(20070228))
Provided and/or discovered by: Sipera VIPER Lab
Changelog: 2007-10-01: Updated advisory based on additional information from Nortel and Sipera Systems. Updated "Solution" section.
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