Symantec AntiVirus Scan Engine Web Service Buffer Overflow Vulnerability

iDEFENSE Security Advisory 10.04.05
www.idefense.com/application/poi/display?id=314&type=vulnerabilities
October 4, 2005

I. BACKGROUND

Symantec Scan Engine is a TCP/IP server and programming interface that 
enables third parties to incorporate support for Symantec content 
scanning technologies into their proprietary applications. More 
information is available from the vendor website: 

http://enterprisesecurity.symantec.com/products/products.cfm?productid=1
73

II. DESCRIPTION

Remote exploitation of a buffer overflow vulnerability in Symantec 
AntiVirus Scan Engine can allow remote attackers to execute arbitrary 
code. 

The vulnerability specifically exists due to insufficient input 
validation of HTTP Headers. A remote attacker can send a specially 
crafted HTTP request to the administrative Scan Engine Web Wervice on 
port 8004 to crash the service or execute arbitrary code. Due to 
improper use of signed integer value types, a negative value can be 
supplied by a connecting client, which will interpret the value as a 
very large number and later use the value as an argument to a memory 
copy operation. An overly long copy will occur resulting in a heap 
overflow. Remote attackers can supply carefully crafted HTTP requests 
to trigger the heap overflow and execute arbitrary code.

III. ANALYSIS

Successful exploitation of the vulnerability can result in remote code 
execution with SYSTEM privileges. Exploitation of the vulnerability 
does not require credentials or any other element in the attack other 
than being able to send a HTTP request to TCP port 8001 on the 
vulnerable server. It is recommended to apply the vendor-supplied 
workaround or upgrade to the latest available version of the software. 

IV. DETECTION

iDEFENSE Labs has confirmed the existence of this vulnerability in 
Symantec AntiVirus Scan Engine 4.0. The vendor has confirmed that the 
vulnerability also effects products utilizing Symantec AntiVirus Scan 
Engine 4.3, however Scan Engine 4.1 is not affected.

V. WORKAROUND

The vendor has supplied the following workaround solution:

"Default installation instructions state that, for security reasons, 
customers should access the administrative interface using a switch or 
via a secure segment of the network. The Symantec AntiVirus Scan Engine 
Administration default port, 8004/tcp, should be locked down for 
trusted internal access only. This port can be changed, as it might 
conflict with existing applications in the environment. But whatever 
port is used for the user-interface, it should never be visible 
external to the network which greatly reduces opportunities for 
unauthorized access. A customer may choose to completely disable the 
Symantec AntiVirus Scan Engine's user-interface once it has been 
satisfactorily configured.

* To disable the user interface, set the port to "0" in the user-
  interface and restart the Symantec AntiVirus Scan Engine. 

* To re-enable the user-interface, edit the Symantec AntiVirus Scan 
  Engine configuration file, set the port back to 8004/tcp, or the 
  applicable user-configured port, and restart the Symantec AntiVirus 
  Scan Engine."

VI. VENDOR RESPONSE

"Symantec Engineers have verified this issue and made security updates
available for the Symantec AntiVirus Scan Engine. Symantec strongly
recommends all customers immediately apply the latest updates for their
supported product versions to protect against these types of threats.
Symantec is unaware of any adverse customer impact from this issue."

A vendor advisory for this issue is available at:

  http://www.symantec.com/avcenter/security/Content/2005.10.04.html

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-2758 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

08/31/2005  Initial vendor notification
08/31/2005  Initial vendor response
10/04/2005  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

infamous41md[at]hotpop.com is credited with this discovery.

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X. LEGAL NOTICES

Copyright (c) 2005 iDEFENSE, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDEFENSE. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.