CVE-2005-0771 in Backup Exec
Summary
by MITRE
VERITAS Backup Exec Server (beserver.exe) 9.0 through 10.0 for Windows allows remote unauthenticated attackers to modify the registry by calling methods to the RPC interface on TCP port 6106.
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Analysis
by VulDB Data Team • 07/04/2025
The vulnerability identified as CVE-2005-0771 affects VERITAS Backup Exec Server versions 9.0 through 10.0 for Windows systems, presenting a critical security flaw in the remote procedure call interface implementation. This issue stems from inadequate authentication mechanisms within the beserver.exe process that operates on TCP port 6106, allowing unauthorized remote attackers to manipulate system registry settings without requiring valid credentials or prior access to the system. The flaw represents a significant weakness in the backup software's security architecture, as it enables arbitrary modification of critical system configuration data through unauthenticated network connections.
The technical exploitation of this vulnerability occurs through the RPC interface exposed by the Backup Exec Server service, where attackers can invoke specific methods that directly interface with the Windows registry. This vulnerability maps to CWE-284 Access Control, specifically representing inadequate access control mechanisms that permit unauthorized modification of system resources. The RPC interface lacks proper authentication checks, allowing any remote entity to establish connections and execute registry modification operations. Attackers can leverage this weakness to inject malicious registry entries, modify existing configurations, or potentially establish persistence mechanisms within the target environment.
The operational impact of this vulnerability extends beyond simple registry modification, as it provides attackers with a means to fundamentally alter system behavior and potentially escalate privileges. By modifying registry entries, attackers could disable security features, modify backup schedules, or redirect backup operations to malicious destinations. This capability aligns with ATT&CK technique T1112 Registry Run Keys and Startup Folder, where adversaries establish persistence through registry modifications. The vulnerability particularly affects enterprise environments where Backup Exec is commonly deployed for critical data protection operations, as it could compromise the integrity of backup processes and potentially allow attackers to manipulate recovery procedures.
Organizations should implement immediate mitigations including network segmentation to restrict access to TCP port 6106, deployment of firewall rules to block external access to the backup server RPC interface, and application of vendor-provided patches to address the authentication bypass. The vulnerability demonstrates the importance of secure RPC implementation practices and highlights the need for proper access control mechanisms in enterprise backup solutions. Security teams should conduct comprehensive network scans to identify affected systems and implement monitoring for suspicious registry modification activities. Additionally, organizations should review their backup infrastructure configurations to ensure that critical services are not exposed to untrusted networks, as this vulnerability represents a classic example of insufficient network boundary protection for critical system services.