CVE-2000-1119 in AIX
Summary
by MITRE
Buffer overflow in setsenv command in IBM AIX 4.3.x and earlier allows local users to execute arbitrary commands via a long "x=" argument.
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Analysis
by VulDB Data Team • 06/05/2024
The vulnerability identified as CVE-2000-1119 represents a critical buffer overflow flaw within the setsenv command of IBM AIX operating systems version 4.3.x and earlier. This issue resides in the command line argument processing mechanism where the setsenv utility fails to properly validate the length of input arguments, specifically the "x=" parameter. The flaw occurs when local users provide an excessively long argument string that exceeds the allocated buffer space, causing memory corruption that can be exploited to execute arbitrary code with elevated privileges. The vulnerability stems from inadequate bounds checking and memory management practices within the system's command processing framework.
The technical implementation of this buffer overflow vulnerability involves the setsenv command's handling of environment variable assignments where the "x=" prefix triggers a specific code path that does not perform proper input validation. When a malicious user supplies a long argument string beginning with "x=", the command processes this input without sufficient boundary checks, leading to memory overwrite conditions that can corrupt the stack or heap memory regions. This memory corruption can be manipulated to redirect program execution flow, allowing attackers to inject and execute malicious code within the context of the running process. The vulnerability specifically aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios.
The operational impact of CVE-2000-1119 extends beyond simple privilege escalation as it provides attackers with a direct path to system compromise through local execution. Since the vulnerability requires only local access to exploit, it can be leveraged by users with minimal system privileges to gain elevated permissions, potentially leading to complete system takeover. The exploitability of this vulnerability is enhanced by the fact that it does not require network access or complex attack vectors, making it particularly dangerous in environments where local user access is not properly restricted. This type of vulnerability can be classified under ATT&CK technique T1068, which focuses on local privilege escalation through exploitation of system vulnerabilities, and T1059, covering command and scripting interpreters used for execution.
Mitigation strategies for this vulnerability should include immediate application of IBM's security patches and updates specifically designed to address the buffer overflow in the setsenv command. System administrators should implement strict access controls to limit local user privileges and monitor for suspicious command execution patterns. The recommended approach involves disabling or restricting usage of the vulnerable setsenv command until proper patches are applied, along with implementing comprehensive logging and monitoring of environment variable manipulation attempts. Additionally, organizations should conduct thorough vulnerability assessments to identify other potential buffer overflow conditions within their AIX systems and apply defensive programming practices such as input validation, bounds checking, and stack canaries to prevent similar issues from occurring in the future.