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Security Advisories Relating to Symantec Products - Symantec Client Proxy Buffer Overflow in Older Product Versions


February 17, 2010

Revision History



Remote Access Yes
Local Access No
Authentication Required No
Exploit publicly available No


The Symantec Client Proxy integrated into older versions of Symantec AntiVirus and Symantec Client Security is vulnerable to a buffer overflow.
Product Version Solution(s)
Symantec AntiVirus 10.0.x Upgrade to SAV 10.1 MR9
10.1.x Upgrade to to MR9
10.2.x Upgrade to MR4
Symantec Client Security 3.0.x Upgrade to SCS 3.1 MR9
3.1.x Upgrade to MR9

Note: Only the Symantec products indicated above shipped with these components.


Symantec was notified of an ActiveX buffer overflow in the Symantec Client Proxy, CLIproxy.dll. The issue impacts the client-side only, is done under the user account and does not lead to an escalation of privilege. It is possible to craft specific HTML webpages that pass information to proxy without proper boundary checking.

The impact of this threat requires user interaction to either click on a link directing them to the specially created html website or otherwise be exposed to said HTML in the constraints of a web browser.

Symantec Response

Symantec product engineers have released a fix for this issue in the MR9 update. Symantec recommends all customers apply the latest available update to protect against threats of this nature.

Symantec is not aware of any exploitation of or adverse customer impact from these issues.

Best Practices

As part of normal best practices, Symantec strongly recommends:

  • Restrict access to administration or management systems to privileged users.
  • Restrict remote access, if required, to trusted/authorized systems only.
  • Run under the principle of least privilege where possible to limit the impact of exploit by threats.
  • Keep all operating systems and applications updated with the latest vendor patches.
  • Follow a multi-layered approach to security. Run both firewall and anti-malware applications, at a minimum, to provide multiple points of detection and protection to both inbound and outbound threats.
  • Deploy network and host-based intrusion detection systems to monitor network traffic for signs of anomalous or suspicious activity. This may aid in detection of attacks or malicious activity related to exploitation of latent vulnerabilities


Symantec would like to thank Alexander Polyakov from DSecRG for reporting these issues and coordinating with us while Symantec resolved them.


BID: Security Focus, http://www.securityfocus.com, has assigned a Bugtraq ID (BID) 38222 to these issues for inclusion in the Security Focus vulnerability database.

CVE: These issues are candidates for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. The CVE initiative has assigned CVE-2010-0108 for the Client Proxy Buffer Overflow
Symantec takes the security and proper functionality of our products very seriously. As founding members of the Organization for Internet Safety (OISafety), Symantec supports and follows responsible disclosure guidelines.
Please contact secure@symantec.com if you feel you have discovered a security issue in a Symantec product. A member of the Symantec Product Security team will contact you regarding your submission to coordinate any required response. Symantec strongly recommends using encrypted email for reporting vulnerability information to secure@symantec.com. The Symantec Product Security PGP key can be found at the location below.
Symantec has developed a Product Vulnerability Response document outlining the process we follow in addressing suspected vulnerabilities in our products. This document is available below.

Copyright (c) by Symantec Corp.

Permission to redistribute this alert electronically is granted as long as it is not edited in any way unless authorized by Symantec Product Security. Reprinting the whole or part of this alert in any medium other than electronically requires permission from secure@symantec.com


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.
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Last modified on: February 17, 2010
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