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Security Advisories Relating to Symantec Products - Symantec Backup Exec Authentication Bypass and Potential Buffer Overflow


November 19, 2008

Revision History




Remote Access (adjacent network)Yes
Local AccessNo
Authentication RequiredNo
Exploit availableNo

*Proof of concept only


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 Products

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.
  • 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 responsible disclosure guidelines.
Symantec has developed a Software Security Vulnerability Management Process document outlining the process we follow in addressing suspected vulnerabilities in our products.
Symantec Corporation firmly believes in a proactive approach to secure software development and implements security review into various stages of the software development process. Additionally, Symantec is committed to the security of its products and services as well as to its customers’ data. Symantec is committed to continually improving its software security process.
This document provides an overview of the current Secure Development Lifecycle (SDLC) practice applicable to Symantec’s product and service teams as well as other software security related activities and policies used by such teams. This document is intended as a summary and does not represent a comprehensive list of security testing and practices conducted by Symantec in the software development process.
Please contact secure@symantec.com if you believe you have discovered a security issue in a Symantec product. A member of the Symantec Software 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 Software Security PGP key can be found at the following location:
Permission to redistribute this alert electronically is granted as long as it is not edited in any way unless authorized by Symantec Software Security. Reprinting the whole or part of this alert in any medium other than electronically requires permission from secure@symantec.com.
Last modified on: November 19, 2008
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