CVE-2000-1012 in FreeBSD
Summary
by MITRE
The catopen function in FreeBSD 5.0 and earlier, and possibly other OSes, allows local users to read arbitrary files via the LANG environmental variable.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 05/28/2018
The vulnerability described in CVE-2000-1012 represents a critical security flaw in the internationalization support mechanisms of FreeBSD systems and potentially other operating systems. This issue resides within the catopen function which is part of the locale handling infrastructure designed to support internationalization and localization features. The vulnerability manifests when the system processes the LANG environment variable, which is commonly used to specify the language and locale settings for applications. When local users manipulate this environment variable inappropriately, they can exploit the function to gain unauthorized access to arbitrary files on the system.
The technical implementation of this vulnerability stems from improper input validation and file access control within the catopen function. When applications or system components invoke catopen to open message catalog files for internationalization purposes, the function fails to properly sanitize the LANG environment variable contents. This lack of proper validation allows attackers to craft malicious values that can cause the function to traverse file system paths in unintended ways. The flaw essentially creates a path traversal vulnerability within the internationalization subsystem, enabling attackers to read files that should normally be restricted or protected.
The operational impact of this vulnerability is significant for systems running affected versions of FreeBSD and potentially other Unix-like operating systems. Local users who can influence the LANG environment variable can access sensitive files such as configuration files, system logs, user credentials, or other confidential data that might be stored in locations accessible to the application using catopen. This represents a privilege escalation vector from a local attacker's perspective, as the ability to read arbitrary files can lead to information disclosure, credential harvesting, and further exploitation opportunities. The vulnerability affects systems where applications rely on internationalization features and may be exploited to gain insights into system configuration and user data.
Security practitioners should implement immediate mitigations including updating to FreeBSD versions 5.1 or later where this vulnerability has been addressed through proper input validation in the catopen function. Additionally, system administrators should review and restrict the LANG environment variable settings in application contexts where sensitive file access is not required. The vulnerability aligns with CWE-22 Path Traversal and CWE-200 Information Disclosure, both of which are fundamental security concerns in system design. From an attacker perspective, this vulnerability fits within the ATT&CK technique T1059 Command and Scripting Interpreter and T1566 Phishing, as it could be exploited through local system access or potentially through crafted environment variable manipulation in specific application contexts. The remediation approach should include comprehensive system patching, environment variable sanitization, and monitoring for unauthorized access attempts to sensitive system files.