Secunia

A weakness has been reported in Sophos Anti-Virus, which can be exploited by malware to bypass certain scanning functionality.

The problem is caused due to an error when parsing .zip archive headers and can be exploited via a specially crafted .zip archive where the uncompressed size of the archived file has been modified within the local and global headers.

Successful exploitation causes malware in a specially crafted .zip archive to pass the scanning functionality undetected.

NOTE: This is not a critical issue on client systems, as the malware still is detected upon execution by the desktop on-access scanner.

Solution
The problem has been fixed in version 3.87.0 of Sophos Anti-Virus on all operating system platforms except Windows 95/98/Me.
Further details available in Customer Area

Provided and/or discovered by
Discovered by anonymous person and reported via iDEFENSE.

Original Advisory
Sophos:
http://sophos.com/support/knowledgebase/article/2074.html

iDEFENSE:
http://www.idefense.com/application/poi/display?id=153&type=vulnerabilities

Deep Links
Links available in Customer Area