Public Vulnerability Reports

Veritas Backup Exec Remote Agent NDMLSRVR.DLL DoS Vulnerability



VERITAS Backup Exec is an advanced backup and restore solution for
Microsoft Windows server environments. More information is available
from the vendor's website:


Remote exploitation of a denial of service condition in Veritas Software
Corp.'s Backup Exec allows attackers to crash the vulnerable service.

The Veritas Backup Exec Agent listens on TCP port 10000 and is
responsible for accepting connections from the backup server when a
backup is to occur. Typically the agent would be installed on most
servers and important workstations in an enterprise environment. Veritas
Backup Exec uses the standard NMDP protocol to communicate with the
listening agents.

The vulnerability specifically exists within NDMLSRVR.DLL due to a null
pointer dereference upon parsing of a maliciously crafted packet at the
following instruction:

    0x01053355 MOVZX EAX, WORD PTR [ESI]

An unhandled exception occurs resulting in a crash of the program and a
denial of service condition.


Exploitation does not require authentication, thereby allowing any
remote attacker to cause the denial of service and disruption of backup


iDEFENSE has confirmed the existence of this vulnerability in Backup
Exec for Windows Servers version 10.0 and 10.0 SP1, the latest versions
available as of this report. It is suspected that older versions are
also vulnerable.

Several vendors ship or use Veritas software including Hitachi and NEC


Use a firewall to restrict incoming connections to trusted workstations
running the Backup Exec client software which uses port 10000 TCP.


The vendor has addressed this vulnerability in security advisory


The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-0772 to this issue. This is a candidate for inclusion
in the CVE list (, which standardizes names for
security problems.


05/13/2005   Initial vendor notification
05/13/2005   Initial vendor response
06/22/2005   Coordinated public disclosure


Sebastian Apelt is credited with this discovery.

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Copyright © 2005 Verisign, Inc.

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