TSRT-06-06: Computer Associates eTrust AntiVirus WebScan Manifest
            Processing Buffer Overflow Vulnerability

http://www.tippingpoint.com/security/advisories/TSRT-06-06.html 
August 7, 2006

-- CVE ID:
CVE-2006-3975

-- Affected Vendor:
Computer Associates

-- Affected Products:
eTrust AntiVirus WebScan v1.1.0.1047 and earlier

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since July 26, 2006 by Digital Vaccine protection
filter ID 4544. For further product information on the TippingPoint IPS:

http://www.tippingpoint.com 

-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
systems with affected installations of the Computer Associates eTrust
AntiVirus WebScan ActiveX component. Successful exploitation requires
that the target user browse to a malicious web page. The vulnerable
component is typically installed as a prerequisite to the free online
WebScan found at:

http://www3.ca.com/securityadvisor/virusinfo/scan.aspx 

The specific flaw exists during WebScan's processing of the actual
manifest files delivered during a scanner update check. It downloads a
'filelist.txt' file from this server, which is used as a manifest file
to describe the updates available. Each line of the file consists of
four fields in the following form:

    [file name] [decimal integer] [decimal integer] [decimal integer]

A lack of bounds checking on the file names specified in update
manifests may lead to a buffer overflow that can be easily exploited to
execute arbitrary code. As WebScan allows the server for update
downloads to be specified on a web page as an initialization parameter,
a malicious manifest can be delivered from any server; it is not
necessary to impersonate a legitimate update server.

-- Vendor Response:
Computer Associates has addressed this issue in the latest version of
their WebScan product. More information from the vendor is available
at:

http://www3.ca.com/securityadvisor/vulninfo/vuln.aspx?id=34509 

-- Disclosure Timeline:
2006.07.17 - Vulnerability reported to vendor
2006.07.26 - Digital Vaccine released to TippingPoint customers
2006.08.07 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by Matthew Murphy, TippingPoint
Security Research Team.

-- About the TippingPoint Security Research Team (TSRT):
The TippingPoint Security Research Team (TSRT) consists of industry
recognized security researchers that apply their cutting-edge
engineering, reverse engineering and analysis talents in our daily
operations. More information about the team is available at:

http://www.tippingpoint.com/security 
 
The by-product of these efforts fuels the creation of vulnerability
filters that are automatically delivered to our customers' intrusion
prevention systems through the Digital Vaccine(R) service.