CVE-2006-6917 in BrightStor ARCserve Backup
Summary
by MITRE
Multiple buffer overflows in Computer Associates (CA) BrightStor ARCserve Backup R11.5 Server before SP2 allows remote attackers to execute arbitrary code in the Tape Engine (tapeeng.exe) via a crafted RPC request with (1) opnum 38, which is not properly handled in TAPEUTIL.dll 11.5.3884.0, or (2) opnum 37, which is not properly handled in TAPEENG.dll 11.5.3884.0.
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Analysis
by VulDB Data Team • 08/16/2024
The vulnerability identified as CVE-2006-6917 represents a critical buffer overflow flaw in Computer Associates BrightStor ARCserve Backup Server version 11.5 before Service Pack 2. This security weakness affects the Tape Engine component specifically through the tapeeng.exe process and manifests in two distinct attack vectors that exploit improper handling of Remote Procedure Call (RPC) operations. The flaw exists within the TAPEUTIL.dll and TAPEENG.dll libraries, both at version 11.5.3884.0, making this a targeted vulnerability that could enable remote code execution with significant system compromise potential.
The technical implementation of this vulnerability stems from inadequate input validation within the RPC handling mechanisms of the BrightStor backup server. When the tapeeng.exe process receives a crafted RPC request with opnum 38 or opnum 37, the application fails to properly validate the size and content of incoming data structures before copying them into fixed-size buffers. This classic buffer overflow condition occurs because the software does not enforce bounds checking on user-supplied data, allowing attackers to overwrite adjacent memory locations with malicious code. The vulnerability specifically affects the TAPEUTIL.dll library when processing opnum 38 and TAPEENG.dll when processing opnum 37, both of which are critical components in the tape backup and recovery operations.
The operational impact of this vulnerability is severe and potentially devastating for organizations relying on CA BrightStor ARCserve Backup systems. Remote attackers who successfully exploit this flaw can execute arbitrary code with the privileges of the tape engine service, which typically runs with elevated system permissions. This could result in complete system compromise, data theft, or disruption of backup operations that are critical for business continuity. The vulnerability is particularly dangerous because it allows remote exploitation without requiring authentication, making it an attractive target for automated attacks and potentially leading to widespread compromise of backup infrastructure across networked environments. Organizations with multiple backup servers running the vulnerable version could face cascading failures if the attack vector is successfully leveraged across their backup infrastructure.
The security implications extend beyond simple code execution to encompass broader system integrity and availability concerns. This vulnerability directly maps to CWE-121, Buffer Overflow in Stack-based Buffer, and CWE-122, Buffer Overflow in Heap-based Buffer, while also aligning with ATT&CK techniques related to remote code execution and privilege escalation. Organizations should immediately implement mitigations including applying the official CA patch for Service Pack 2, which addresses the specific buffer overflow conditions in both TAPEUTIL.dll and TAPEENG.dll. Network segmentation and firewall rules should be implemented to restrict RPC access to the backup server, particularly on the ports used for tape engine communications. Additionally, monitoring for unusual RPC traffic patterns and implementing intrusion detection systems can help identify potential exploitation attempts. The vulnerability underscores the critical importance of maintaining up-to-date security patches and the potential risks associated with legacy backup infrastructure that may not receive continued support or security updates from vendors.