CVE-2000-1121 in AIX
Summary
by MITRE
Buffer overflow in enq command in IBM AIX 4.3.x and earlier may allow local users to execute arbitrary commands via a long -M argument.
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Analysis
by VulDB Data Team • 06/05/2024
The vulnerability described in CVE-2000-1121 represents a critical buffer overflow flaw within the enq command of IBM AIX operating systems version 4.3.x and earlier. This issue specifically manifests when processing the -M argument, which is used for specifying message queues in the AIX environment. The enq command serves as a utility for managing and manipulating message queues within the AIX system, making it a crucial component for inter-process communication and system administration tasks. The buffer overflow occurs due to insufficient input validation and bounds checking when handling the -M argument, allowing maliciously crafted input to overwrite adjacent memory locations in the program's execution stack.
The technical exploitation of this vulnerability stems from the fundamental flaw in memory management within the enq command implementation. When a local user provides an excessively long argument to the -M flag, the command fails to properly validate the input length against the allocated buffer size. This allows the attacker to overwrite critical memory segments including return addresses, stack canaries, or other control data structures. The vulnerability is classified as a classic stack-based buffer overflow, which aligns with CWE-121, representing the weakness of insufficient bounds checking on buffers. This type of vulnerability falls under the broader category of memory corruption vulnerabilities that have been extensively documented in cybersecurity literature and represent one of the most common attack vectors for privilege escalation and arbitrary code execution.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it provides attackers with the ability to execute arbitrary commands with the privileges of the enq process. This capability can be leveraged to gain unauthorized access to system resources, escalate privileges to root level, or potentially compromise the entire system. Local users who can execute the enq command can exploit this vulnerability to bypass normal access controls and execute malicious payloads. The attack vector is particularly concerning because it requires minimal privileges to initiate and can be executed without network access, making it a significant threat in environments where local access is not properly restricted. From an attacker's perspective, this vulnerability represents a low-effort, high-impact method for gaining system control, as demonstrated by the attack techniques outlined in the MITRE ATT&CK framework under the privilege escalation tactics.
Mitigation strategies for this vulnerability should include immediate patching of affected IBM AIX systems to the latest available security fixes from IBM. Organizations should implement strict input validation and bounds checking mechanisms to prevent similar issues in custom applications. The principle of least privilege should be enforced to limit local user access to critical system commands, while regular security audits should be conducted to identify potential buffer overflow vulnerabilities in legacy systems. System administrators should also consider implementing monitoring and logging mechanisms to detect suspicious command execution patterns. Additionally, the vulnerability highlights the importance of proper software development practices including code reviews, static analysis tools, and dynamic testing procedures to identify and prevent similar memory corruption issues in application code. Organizations maintaining legacy AIX systems should also consider migrating to more modern operating systems with better security features and active support cycles to avoid similar vulnerabilities in the future.