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August 16, 2007
Symantec Enterprise Firewall and Symantec Gateway Security Username Enumeration

Revision History
August 24, 2007: Added Symantec Gateway Security products and clarified workarounds.


Remote AccessYes
Local AccessNo
Authentication RequiredNo
Exploit publicly availableNo

Symantec Enterprise Firewall username information can be verified through an exposure in the login interface.

Affected Products
Symantec Enterprise Firewall (Solaris)8.0AllWorkaround
Symantec Gateway Security 300 Series2.1AllWorkaround
Symantec Gateway Security 400 Series2.1AllWorkaround
Symantec Gateway Security 1600 Series3.0.1AllWorkaround
Symantec Gateway Security 5000 Series3.0.1AllWorkaround

Note: Workarounds for this exposure are described in the Symantec Response and Workaround section below.

When the Symantec Enterprise Firewall is configured for remote access (client-to-gateway) VPN using pre-shared key (PSK) authentication, it responds differently to valid and invalid usernames. This exposure could be used to determine if a guessed username is valid. It does not list valid usernames. It can only be used to identify if a given username exists.

Symantec Response and Workaround
Symantec engineers have verified this exposure. For the SGS 300/400 series products, enabling the "Dynamic VPN Client" feature and entering a pre-shared key will fix the problem. For all other products, adding an IKE-enabled network user named "default-ikeuser" and configuring it with a shared secret resolves the problem. This username is used for extended authentication to a separate authentication server. However, extended authentication is not needed for this workaround to be effective.

Symantec recommends that Symantec Enterprise Firewall administrators who are concerned about this exposure apply the appropriate workaround noted above.

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

SecurityFocus, http://www.securityfocus.com, has assigned a Bugtraq ID(BID) to this issue for inclusion in the SecurityFocus vulnerability data base. The BID assigned is 25338 which can be found at http://www.securityfocus.com/bid/25338.

Symantec would like to thank Roy Hill of NTA Monitor Ltd for reporting this issue and for providing full coordination while Symantec resolved it.

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 the principles of responsible disclosure. Symantec also subscribes to the vulnerability disclosure guidelines outlined by the National Infrastructure Advisory Council (NIAC).

Please contact secure@symantec.com if you feel you have discovered a security issue in a Symantec product. A Symantec Product Security team member will contact you regarding your submission. 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 end of this message.

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.

PDF Symantec Vulnerability Response Policy PGP Symantec Product Vulnerability Management PGP Key

Copyright © 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 Security Response. 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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Initial Post on: Wednesday, 13-Aug-07 14:30:00
Last modified on: Monday, 27-Aug-2007 11:27:40 PDT
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