CVE-2006-6076 in BrightStor ARCserve Backup
Summary
by MITRE
Buffer overflow in the Tape Engine (tapeeng.exe) in CA (formerly Computer Associates) BrightStor ARCserve Backup 11.5 and earlier allows remote attackers to execute arbitrary code via certain RPC requests to TCP port 6502.
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Analysis
by VulDB Data Team • 04/28/2026
The vulnerability identified as CVE-2006-6076 represents a critical buffer overflow flaw within the Tape Engine component of CA BrightStor ARCserve Backup software versions 11.5 and earlier. This issue specifically affects the tapeeng.exe executable which serves as the core component responsible for tape backup operations within the backup solution. The vulnerability manifests when the software processes certain Remote Procedure Call (RPC) requests transmitted over TCP port 6502, which is the default port used by the BrightStor backup service for remote management and backup operations. The buffer overflow condition occurs due to inadequate input validation and bounds checking within the RPC processing logic, creating a scenario where maliciously crafted RPC requests can overwrite adjacent memory locations in the tapeeng.exe process.
The technical exploitation of this vulnerability enables remote attackers to execute arbitrary code with the privileges of the user running the tapeeng.exe process, typically the SYSTEM account on Windows systems. This occurs because the buffer overflow allows attackers to overwrite the return address on the stack or other critical memory structures, effectively redirecting program execution flow to malicious code injected by the attacker. The flaw is particularly dangerous as it operates over a network port, eliminating the need for local system access or authentication. The vulnerability follows the common pattern of stack-based buffer overflows, which are categorized under CWE-121 in the Common Weakness Enumeration system, specifically representing insufficient bounds checking in memory allocation scenarios. The attack vector leverages the RPC interface to deliver malformed data that exceeds the allocated buffer space, leading to memory corruption and potential code execution.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with complete control over the backup server system. The BrightStor ARCserve Backup solution typically manages critical enterprise backup operations and may have access to sensitive data repositories, making this vulnerability particularly attractive to threat actors. Once compromised, attackers can manipulate backup operations, steal backup data, or use the compromised system as a pivot point for further attacks within the network. The vulnerability affects organizations using older versions of the software, which may have been deployed in enterprise environments where backup servers are often configured with elevated privileges and have access to extensive data stores. This represents a significant security risk as it allows attackers to gain unauthorized access to backup infrastructure without requiring legitimate credentials, potentially compromising the integrity and availability of backup systems that are critical for business continuity.
Mitigation strategies for CVE-2006-6076 should prioritize immediate software updates and patches provided by CA, as the vendor would have released a fix addressing the buffer overflow condition in subsequent versions of the BrightStor ARCserve Backup software. Organizations should implement network segmentation to restrict access to TCP port 6502, limiting exposure to only trusted network segments and administrative workstations. Additional protective measures include disabling the RPC service entirely if not required, implementing network access controls through firewalls, and monitoring for unusual RPC traffic patterns on the affected port. The vulnerability aligns with ATT&CK technique T1059.007 for remote code execution through RPC interfaces and represents a classic example of how backup infrastructure can become a critical attack surface in enterprise environments. Regular vulnerability assessments and network scanning should be conducted to identify unpatched systems running vulnerable versions of the software, while security monitoring should specifically target anomalous behavior on TCP port 6502 that could indicate exploitation attempts. Organizations should also consider implementing intrusion detection systems that can identify and alert on malformed RPC requests that attempt to exploit this specific buffer overflow condition.