CVE-2002-0246 in UnixWare
Summary
by MITRE
Format string vulnerability in the message catalog library functions in UnixWare 7.1.1 allows local users to gain privileges by modifying the LC_MESSAGE environment variable to read other message catalogs containing format strings from setuid programs such as vxprint.
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Analysis
by VulDB Data Team • 04/03/2025
This vulnerability exists in the message catalog library functions of UnixWare 7.1.1 operating system, representing a classic format string flaw that can be exploited by local attackers to escalate privileges. The vulnerability specifically manifests when the LC_MESSAGE environment variable is manipulated to point to alternative message catalog files that contain crafted format strings. These format strings are then processed by setuid programs such as vxprint, which are designed to run with elevated privileges. The flaw stems from improper input validation within the message catalog processing routines, where user-controlled data from environment variables is directly used in printf-style functions without adequate sanitization. This creates a condition where malicious format specifiers can be injected into the program execution flow, potentially allowing attackers to read arbitrary memory locations, execute arbitrary code, or manipulate program behavior. The vulnerability is particularly dangerous because it leverages the trust model of setuid programs, which are typically designed to operate with elevated privileges to perform system-level operations. When exploited, this vulnerability can enable local users to gain privileges that would normally be restricted to system administrators or root users. The attack vector is straightforward: an attacker modifies the LC_MESSAGE environment variable to reference a specially crafted message catalog file containing malicious format strings, then executes a setuid program that processes these catalogs. This type of vulnerability is categorized under CWE-134 which specifically addresses the use of format strings with user-supplied data, making it a well-documented weakness in software security practices. The operational impact extends beyond simple privilege escalation as it can potentially lead to complete system compromise, given that setuid programs often have broad system access capabilities. The exploitation requires local access but can result in significant security breaches, particularly in multi-user environments where privilege separation is critical. According to ATT&CK framework, this vulnerability maps to privilege escalation techniques where adversaries leverage insecure library functions to gain elevated system access. The vulnerability represents a fundamental flaw in input handling and environment variable processing within system libraries, highlighting the importance of robust input validation and secure coding practices. Security practitioners should note that this vulnerability is particularly concerning because it affects core system libraries and can be exploited through simple environment variable manipulation, making it accessible to attackers with minimal technical expertise. The fix typically involves patching the message catalog processing functions to properly sanitize user-supplied input and prevent format string injection attacks, or implementing stricter validation of environment variable contents before they are processed by system utilities. Organizations should ensure that UnixWare systems are updated with appropriate patches to address this vulnerability and prevent potential exploitation by malicious actors seeking to escalate privileges within their environments.