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19 November, 2008
Symantec Backup Exec Authentication Bypass and Potential Buffer Overflow

Revision History


Remote AccessYes
Local AccessNo
Authentication RequiredNo
Exploit publicly availableNo

Vulnerabilities were found in the authentication methods for logging onto a Backup Exec Remote Agent for Windows, Linux/Unix, Macintosh and Remote Media Agent for Linux Servers, that could allow an unprivileged user to gain unauthorized access to the application. Once authenticated, the user could further leverage a potential buffer overflow in the data management protocol in an attempt to crash or possibly further compromise the targeted system.

Affected Product
Symantec Backup Exec for Windows Server 12.52213Hotfix Available
Symantec Backup Exec for Windows Server 121364Hotfix Available
Symantec Backup Exec for Windows Server 11d7170Hotfix Available
Symantec Backup Exec for Windows Server 11d6235Hotfix Available

Note: ONLY the product versions and builds listed above as affected are vulnerable to these issues. This impacts the remote agents present on both Media servers and Remote backup hosts.

Tenable Network Security worked with Symantec to identify multiple vulnerability issues in authentication as well as a buffer overflow potential once authenticated on affected Symantec Backup Exec remote agents. An unprivileged but authorized network user could potentially bypass the authentication during the logon process with the Backup Exec remote agents. Access could allow the unauthorized user to retrieve or delete files from the targeted host. Once authenticated, a potential buffer overflow is present in the data management protocol that could allow the unauthorized user to crash or possibly further compromise the targeted system.

Symantec Response
Symantec product engineers have developed and released solutions for this issue through Symantec's LiveUpdate capability and support channels as indicated.
Symantec recommends all customers apply all updates to protect against threats of this nature.
Symantec knows of no exploitation of or adverse customer impact from these issues.

Technical documentation concerning this issue is available from:


Symantec has released an IPS signature to detect and block attempts to exploit the buffer overflow (BID 32346).

Best Practices
As part of normal best practices, Symantec strongly recommends a multi-layered approach to security

  • Run under the principle of least privilege where possible.
  • Keep all operating systems and applications updated with the latest vendor patches.
  • Users, at a minimum, should run both a personal firewall and antivirus application with current updates to provide multiple points of detection and protection to both inbound and outbound threats.
  • Users should be cautious of mysterious attachments and executables delivered via email and be cautious of browsing unknown/untrusted websites or opening unknown/untrusted URL links.
  • Do not open unidentified attachments or executables from unknown sources or that you didn't request or were unaware of.
  • Always err on the side of caution. Even if the sender is known, the source address may be spoofed.
  • If in doubt, contact the sender to confirm they sent it and why before opening the attachment. If still in doubt, delete the attachment without opening it.

Symantec would like to thank Renaud Deraison and Nicolas Pouvesle with Tenable Network Security for coordinating on these findings and working closely with Symantec as the issues were resolved.

Security Focus, http://www.securityfocus.com, has assigned a Bugtraq ID (BID) to these issues for inclusion in the Security Focus vulnerability database. BID 32347 has been assigned to the authentication bypass issue and BID 32346 has been assigned to the buffer overflow in the data management protocol.

A CVE Candidate name will be requested from the Common Vulnerabilities and Exposures (CVE) initiative for these issues. This advisory will be revised accordingly upon receipt of the CVE Candidate names. These issues are candidates for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems.

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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Last modified on: Wednesday, 19-Nov-2008 14:59:51 PST
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