CVE-2001-0641 in man
Summary
by MITRE
Buffer overflow in man program in various distributions of Linux allows local user to execute arbitrary code as group man via a long -S option.
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Analysis
by VulDB Data Team • 10/14/2024
The vulnerability described in CVE-2001-0641 represents a classic buffer overflow flaw within the man program across multiple Linux distributions, creating a significant security risk for local users. This issue stems from inadequate input validation when processing command-line arguments, specifically the -S option which is used to specify the section number for manual pages. The flaw allows an attacker with local access to potentially escalate privileges and execute arbitrary code with the privileges of the group man, which is a critical system group responsible for managing manual pages and related documentation files.
The technical implementation of this vulnerability occurs when the man program processes an excessively long argument for the -S option without proper bounds checking. This oversight creates a writable buffer that can be overwritten beyond its allocated memory space, leading to potential stack corruption and arbitrary code execution. The buffer overflow specifically targets the program's argument parsing mechanism, where the length of the section specification parameter is not properly validated against the buffer size. This type of vulnerability falls under CWE-121, which addresses stack-based buffer overflow conditions, and is particularly dangerous because it operates within a privileged context that could be exploited by local users to gain elevated system access.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides a pathway for local attackers to execute malicious code with group-level permissions. The group man typically has specific access rights to manual page files and related system documentation, making this privilege escalation particularly concerning for system integrity. Attackers could leverage this vulnerability to modify system documentation, potentially creating backdoors or hiding malicious activities within the system's documentation structure. The exploitability of this vulnerability is relatively straightforward, requiring only local access to the system and knowledge of the specific command-line argument that triggers the buffer overflow condition. This makes it a particularly attractive target for attackers who have already gained local access to a system but seek to elevate their privileges.
Mitigation strategies for CVE-2001-0641 should focus on immediate patching of affected man programs across all Linux distributions, as well as implementing proper input validation and bounds checking in the argument parsing routines. System administrators should ensure that all packages containing the man program are updated to versions that include proper buffer overflow protections, including stack canaries and address space layout randomization where applicable. The vulnerability also highlights the importance of input sanitization and the principle of least privilege in system design, as the man program should not require elevated group permissions to function normally. Additionally, monitoring for unusual usage patterns of the man command, particularly with long arguments, can help detect potential exploitation attempts. Organizations should consider implementing automated patch management systems to prevent such vulnerabilities from remaining unaddressed in production environments, as this type of flaw represents a persistent risk that can be exploited by both malicious insiders and external attackers who have gained local access to systems.