CVE-2001-1178 in X11r6
Summary
by MITRE
Buffer overflow in xman allows local users to gain privileges via a long MANPATH environment variable.
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Analysis
by VulDB Data Team • 11/17/2024
The vulnerability described in CVE-2001-1178 represents a classic buffer overflow flaw within the xman utility, which is part of the X Window System documentation viewer. This issue specifically affects the handling of environment variables, particularly the MANPATH variable that controls where manual pages are searched for. The flaw occurs when the xman application processes a specially crafted MANPATH environment variable that exceeds the allocated buffer size, leading to memory corruption that can be exploited by local attackers to elevate their privileges on the system.
This buffer overflow vulnerability falls under the CWE-121 category of "Stack-based Buffer Overflow" and demonstrates poor input validation practices in the xman application. The vulnerability is particularly concerning because it operates at the local privilege level, meaning that any user with access to the system can potentially exploit it to gain elevated permissions. The flaw exists in the way the application parses and stores the MANPATH environment variable without proper bounds checking, allowing an attacker to overwrite adjacent memory locations including return addresses and other critical program data structures.
The operational impact of this vulnerability extends beyond simple privilege escalation as it can be leveraged to execute arbitrary code with the privileges of the xman process, which typically runs with elevated permissions. Attackers can construct a malicious MANPATH environment variable that overflows the buffer and redirects program execution flow to malicious code. This type of vulnerability is particularly dangerous in multi-user environments where local access might be more easily obtained than remote access, and it can serve as a foothold for more extensive system compromise. The attack vector is relatively simple and does not require sophisticated network access, making it particularly attractive to attackers who can gain local shell access.
Mitigation strategies for this vulnerability should include immediate application of vendor patches or updates that implement proper buffer size validation and bounds checking for environment variable processing. System administrators should also consider implementing privilege separation mechanisms where possible, ensuring that the xman utility does not run with elevated privileges when possible. Additionally, the principle of least privilege should be enforced by limiting local user access to potentially vulnerable applications and monitoring for unusual environment variable modifications. The vulnerability demonstrates the importance of input validation and memory safety practices in system utilities, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploits. Organizations should also implement regular security audits of system utilities and environment variable handling to prevent similar issues from occurring in other applications that may be vulnerable to the same class of buffer overflow attacks.