CVE-2005-3396 in AIX
Summary
by MITRE
Buffer overflow in the chcons (chcon) command in IBM AIX 5.2 and 5.3, when DEBUG MALLOC is enabled, might allow attackers to execute arbitrary code via a long command line argument.
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Analysis
by VulDB Data Team • 07/05/2019
The vulnerability identified as CVE-2005-3396 represents a critical buffer overflow flaw within the chcon command of IBM AIX operating systems version 5.2 and 5.3. This issue specifically manifests when the DEBUG MALLOC feature is enabled, creating a condition where maliciously crafted command line arguments can trigger unauthorized code execution. The chcon command, which serves to change file security contexts within the AIX environment, becomes a vector for privilege escalation when exploited properly. This vulnerability falls under the CWE-121 category of Buffer Overflow, specifically classified as a stack-based buffer overflow that occurs during command line argument processing. The operational context reveals that this flaw is particularly dangerous in environments where administrative privileges are required to execute the chcon command, as attackers could leverage this vulnerability to gain elevated system access.
The technical implementation of this buffer overflow stems from inadequate input validation within the chcon command's argument parsing mechanism. When DEBUG MALLOC is enabled, the system allocates additional memory for debugging purposes but fails to properly enforce bounds checking on command line argument lengths. Attackers can craft command line arguments that exceed the allocated buffer space, causing memory corruption that can be manipulated to redirect program execution flow. The vulnerability exploits the inherent trust placed in command line inputs without sufficient sanitization, allowing attackers to overwrite adjacent memory locations including return addresses and function pointers. This type of exploitation aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries leverage command line interfaces to execute malicious payloads. The memory corruption pattern typical of this vulnerability enables attackers to inject and execute arbitrary code with the privileges of the process executing chcon.
The operational impact of CVE-2005-3396 extends beyond simple privilege escalation to encompass potential system compromise and data integrity violations. An attacker who successfully exploits this vulnerability can execute code with the same privileges as the chcon command, which typically runs with elevated permissions due to its security context modification capabilities. This presents a significant risk in multi-user environments where unauthorized users might attempt to exploit the vulnerability to gain unauthorized access to sensitive system resources. The vulnerability's exploitation requires minimal privileges to initially access the chcon command but can result in full system compromise. Organizations running IBM AIX 5.2 and 5.3 systems are particularly vulnerable as these versions lack proper input validation mechanisms and do not implement stack canary protections against such buffer overflow conditions. The impact is further amplified by the fact that many administrative tasks require the execution of chcon commands, making this vulnerability a prime target for attackers seeking persistent system access.
Mitigation strategies for CVE-2005-3396 should prioritize immediate system hardening through disabling DEBUG MALLOC functionality when it is not actively required for debugging purposes. Organizations must implement strict input validation procedures for all command line arguments, particularly those that interface with security-critical commands like chcon. The recommended approach involves upgrading to patched versions of IBM AIX 5.2 and 5.3, as IBM released security updates specifically addressing this buffer overflow vulnerability. System administrators should also implement monitoring solutions that can detect anomalous command line argument lengths and suspicious chcon usage patterns. Additionally, privilege separation mechanisms should be enforced to limit the execution scope of chcon commands, ensuring that only authorized administrators can invoke these security-critical operations. Network segmentation and access control measures should be implemented to restrict potential attack vectors, while regular security audits should verify that DEBUG MALLOC is disabled in production environments. The implementation of automated patch management systems ensures timely application of security updates, reducing the window of exposure for this and similar vulnerabilities. Organizations should also consider implementing application whitelisting policies that restrict execution of unauthorized binaries that might be used to exploit this vulnerability through indirect attack vectors.