Vulnerability Note VU#107822

Symantec products vulnerable to buffer overflow via a specially crafted UPX file

The AntiVirus Library DEC2EXE component contains a flaw in virtual file offset checking that can result in a heap overflow condition and the ability for an attacker to execute arbitrary code contained within the UPX file being scanned. Before the UPX file is uncompressed, the Portable Executable (PE) header is reconstructed. If a negative file offset to a crafted PE header is specified, and this crafted header contains malicious information, subsequent bounds calculations involving data from the legitimate PE header will result in a heap overflow.

II. Impact

Updates for Symantec products are provided through the LiveUpdate functionality of the product or from the Symantec Product Support web page.

In the meantime, Symantec Security Response Bulletin SYM05-003 provides a number of workarounds to disable or remove the DEC2EXE module.

Systems Affected

http://www.sarc.com/avcenter/security/Content/2005.02.08.html
http://www.sarc.com/avcenter/venc/data/bloodhound.exploit.26.html
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2005020911112648
http://xforce.iss.net/xforce/alerts/id/187
http://secunia.com/advisories/14179/
http://securitytracker.com/alerts/2005/Feb/1013133.html

Credit

Thanks to Alex Wheeler and the rest of the ISS X-Force for reporting this vulnerability.

This document was written by Ken MacInnis and is based primarily on information provided by ISS X-Force and Symantec.

Other Information

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