Veritas Backup Exec Agent Browser Registration Request Buffer Overflow
Vulnerability

iDEFENSE Security Advisory 12.16.04
http://www.idefense.com/application/poi/display?id=169
December 16, 2004

I. BACKGROUND

Backup Exec is a next generation backup and restore solution for
Microsoft Windows server environments. More information is available
here:

http://veritas.com/Products/www?c=product&refId=57

II. DESCRIPTION

Remote exploitation of a stack-based buffer overflow vulnerability in
Veritas Backup Exec allows attackers to execute arbitrary code.

The vulnerability specifically exists within the function responsible
for receiving and parsing registration requests. The registration
request packet contains the hostname and connecting TCP port of the
client which is stored in an array on the stack. An attacker can send a
registration request with an overly long hostname value to overflow the
array and take control of the saved return address to execute arbitrary
code.

III. ANALYSIS

Successful exploitation does not require authentication thereby allowing
any remote attacker to execute arbitrary code under the privileges of
the Backup Exec Agent Browser (benetns.exe) process which is usually a
domain administrative account.

IV. DETECTION

iDEFENSE has confirmed the existence of this vulnerability in Backup
Exec for Windows Servers 9.1.

V. WORKAROUND

Use a firewall to restrict incoming connections to trusted workstations
running the Backup Exec client software.

VI. VENDOR RESPONSE

8.60.3878 Hotfix 68 - Backup Exec
(Buffer overflow creates a security hole in Agent Browser)

   http://seer.support.veritas.com/docs/273422.htm

9.1.4691 Hotfix 40 - Backup Exec
(Buffer overflow creates a security hole in Agent Browser;
Licensed Storage Central becomes Eval when Backup Exec 9.1 is uninstalled)
*Requires Backup Exec 9.1.4691 Service Pack 1

   http://seer.support.veritas.com/docs/273420.htm

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2004-1172 to these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

11/02/2004   Initial vendor contact
12/16/2004   Initial vendor response
12/16/2004   Public disclosure

IX. CREDIT

An anonymous contributor and Patrik Karlsson (http://www.cqure.net) are
credited with discovering this vulnerability.

Get paid for vulnerability research
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X. LEGAL NOTICES

Copyright (c) 2004 iDEFENSE, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
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part of this alert in any other medium other than electronically, please
email customerservice@idefense.com for permission.

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.