CVE-2001-1179 in X11r6
Summary
by MITRE
xman allows local users to gain privileges by modifying the MANPATH to point to a man page whose filename contains shell metacharacters.
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Analysis
by VulDB Data Team • 05/31/2018
The vulnerability described in CVE-2001-1179 represents a privilege escalation flaw within the xman utility, a graphical interface for viewing manual pages on Unix-like systems. This issue arises from the improper handling of environment variables, specifically the MANPATH variable, which controls where the system searches for manual pages. The vulnerability is classified under CWE-22 as Improper Limitation of a Pathname to a Restricted Directory, and it demonstrates how seemingly innocuous environment variable manipulation can lead to significant security implications. When local users exploit this weakness, they can potentially elevate their privileges from standard user level to root access, making it a critical concern for system administrators.
The technical flaw occurs when the xman utility processes manual pages and fails to properly sanitize or validate the filenames within the MANPATH environment variable. If an attacker can manipulate the MANPATH to include a directory containing a manual page with shell metacharacters in its filename, the utility may execute unintended commands during the rendering process. This vulnerability leverages the principle of command injection, where the system interprets special characters in filenames as shell commands rather than literal text. The flaw is particularly dangerous because it operates at the user level but can potentially be exploited to gain elevated privileges through the execution of arbitrary code with higher permissions. The vulnerability aligns with ATT&CK technique T1068 which covers the exploitation of legitimate system tools for privilege escalation.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can be used to establish persistent access to systems and potentially compromise entire networks. Attackers can craft malicious manual pages with filenames containing shell metacharacters such as semicolons, ampersands, or backticks that get executed when xman processes them. This creates a vector for remote code execution and system compromise, particularly in environments where users might have the ability to modify environment variables or where xman is run with elevated privileges. The vulnerability affects systems where xman is installed and accessible to local users, making it particularly relevant in multi-user environments or shared computing systems. Organizations using this utility are at risk of unauthorized access and data breaches, as the exploitation requires minimal privileges and can be automated.
Mitigation strategies for CVE-2001-1179 should focus on both immediate defensive measures and long-term architectural improvements. System administrators should ensure that the xman utility is properly configured to validate and sanitize all input from environment variables, particularly MANPATH. The most effective immediate solution involves restricting user access to modify the MANPATH variable or implementing proper input validation that prevents shell metacharacters from being interpreted as commands. Organizations should also consider implementing privilege separation where the xman utility runs with minimal necessary permissions, preventing potential escalation from occurring even if the vulnerability is exploited. Additionally, regular security audits should verify that no malicious manual pages exist in the system's manpath directories, and monitoring should be implemented to detect unusual activity related to manual page processing. The vulnerability highlights the importance of secure coding practices and proper input validation, as emphasized in industry standards such as the OWASP Top Ten and NIST guidelines for secure software development.