CVE-2003-0087 in libIM Library
Summary
by MITRE
Buffer overflow in libIM library (libIM.a) for National Language Support (NLS) on AIX 4.3 through 5.2 allows local users to gain privileges via several possible attack vectors, including a long -im argument to aixterm.
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Analysis
by VulDB Data Team • 06/05/2024
The vulnerability identified as CVE-2003-0087 represents a critical buffer overflow flaw within the libIM library component of AIX operating systems version 4.3 through 5.2. This library serves as part of the National Language Support infrastructure, providing internationalization capabilities for applications running on AIX platforms. The flaw specifically manifests in the handling of command-line arguments, particularly when processing the -im parameter within the aixterm terminal emulator. The buffer overflow vulnerability arises from insufficient input validation and bounds checking mechanisms within the library's argument parsing routines, creating an exploitable condition that can be leveraged by local attackers to escalate privileges.
The technical implementation of this vulnerability stems from improper memory management within the libIM library's processing of the -im command-line argument. When aixterm receives a long -im argument, the library fails to properly validate the input length against the allocated buffer space, allowing attackers to overwrite adjacent memory locations. This overflow can potentially corrupt critical program data structures, function return addresses, or other memory regions that control program execution flow. The vulnerability is classified as a classic stack-based buffer overflow, where the attacker-controlled input exceeds the allocated buffer size, enabling arbitrary code execution with the privileges of the target process. The flaw exists at the intersection of CWE-121, stack-based buffer overflow, and CWE-122, heap-based buffer overflow, though the specific implementation demonstrates stack-based characteristics due to the nature of the argument processing.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and unauthorized access to sensitive system resources. Local attackers who can execute commands on the target system can leverage this flaw to elevate their privileges from standard user level to root or administrative access, depending on the execution context and target application. The vulnerability affects the entire AIX 4.3 through 5.2 product line, making it particularly concerning for organizations running legacy systems that may not have received subsequent security updates. Attackers can exploit this through multiple vectors including direct invocation of aixterm with malicious arguments, or through applications that utilize the libIM library and pass untrusted input to the affected functions. The exploitability of this vulnerability is enhanced by the fact that it requires minimal privileges to trigger and can be executed without network access, making it particularly dangerous in environments where local access is possible.
Organizations affected by CVE-2003-0087 should implement immediate mitigations including applying the vendor-provided security patches for AIX systems, implementing input validation controls for command-line arguments, and monitoring system logs for suspicious aixterm usage patterns. The recommended approach includes disabling or restricting the use of the affected -im argument when possible, implementing proper bounds checking in application code, and ensuring that all AIX systems are updated to versions that contain the patched libIM library. Security controls should also include monitoring for unauthorized privilege escalation attempts and implementing least privilege principles to limit the potential impact of successful exploitation. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068, 'Exploitation for Privilege Escalation', with potential lateral movement implications if attackers can use the elevated privileges to access other systems or resources within the network environment.