Advisory: Clamav generic evasion (CAB)

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Release mode: Coordinated but limited disclosure
Ref : [TZO-40-2009] - Clamav generic evasion (CAB)
Vendor : http://www.clamav.net &
http://www.sourcefire.com/products/clamav
Status : Patched (in version 0.95.2)
CVE : none provided
Security notification reaction rating : good


Disclosure Policy : http://blog.zoller.lu/2008/09/notification-and-disclosure-policy.html

Affected products :
- ClamAV below 0.95.2

Affected systems:
- MACOSX server,
- IBM Secure E-mail Express Solution for System
Others : http://www.clamav.net/about/who-use-clamav/

I. Background
Quote: "Clam AntiVirus is an open source (GPL) anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail gateways. It provides a number of utilities including a flexible and scalable multi-threaded
daemon, a command line scanner and advanced tool for automatic database updates. The core of the package is an anti-virus engine available in a form of shared library. "

II. Description
The parsing engine can be bypassed by manipulating CAB (Filesize) archives in a "certain way" that the Clamav engine cannot extract the content but the end user is able to.

III. Impact
To know more about the impact and type of "evasion", I updated the  description at http://blog.zoller.lu/2009/04/case-for-av-bypassesevasions.html

IV. Disclosure timeline
DD/MM/YYYY

Nothing particular too note.