Check Point Advisories

Sophos Anti-Virus CAB File Invalid Folder Count Heap Overflow (CVE-2006-0994)

Vulnerability
Protection

Check Point Reference:	CPAI-2006-193
Date Published:	14 Oct 2009
Severity:	High
Last Updated:	Tuesday 17 June, 2014
Source:
Industry Reference:	CVE-2006-0994
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?
Vulnerability Description	Sophos Anti-Virus (AV) is a product that provides virus scanning functionality for desktop and server systems. It can scan files on the local system or files downloaded from the network for known viruses, Trojans, and other malicious programs. The AV product is capable of interpreting numerous compression formats and algorithms, one of which is the Windows CAB archive format. There exists a heap overflow vulnerability in Sophos Anti-Virus as well as many other Sophos products that embed it. The vulnerability exists in the component that handles Microsoft CAB compressed files. A remote unauthenticated attacker can exploit the vulnerability causing a denial of service condition or the execution of arbitrary code within the security context of the Anti-Virus service, normally System. In a simple attack case aimed at creating a denial of service condition, the on-demand Sophos Anti-Virus console will freeze, the Sophos Anti-Virus service and on-access scanning functionality will also stop working. The service and all other Anti-Virus functions will not resume until the target computer is restarted or the "Sophos Anti-Virus" service is restarted manually. Note that in order to restart the service, the SavService.exe process needs to be terminated if it is still being executed. Furthermore, the application that calls Sophos Anti-Virus, such as Windows Explorer, may also freeze on accessing the malformed CAB files. In a more sophisticated attack scenario, where the malicious user is successful in injecting and executing supplied code, the behaviour of the system is dependent on the nature the injected code. Any code injected into the vulnerable component would execute in the security context of the affected service, normally System.

Protection Overview

This protection will detect and block attempts to download files via HTTP that exploit this vulnerability

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R80 / R77 / R75

In the IPS tab, click Protections and find the Sophos Anti-Virus CAB File Invalid Folder Count Heap Overflow protection using the Search tool and Edit the protection's settings.
Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name: Security Products Enforcement Violation.
Attack Information: Sophos Anti-Virus CAB file invalid folder count heap overflow