CVE-2001-0221 in ja-xklock
Summary
by MITRE
Buffer overflow in ja-xklock 2.7.1 and earlier allows local users to gain root privileges.
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Analysis
by VulDB Data Team • 06/19/2024
The vulnerability identified as CVE-2001-0221 represents a critical buffer overflow flaw within the ja-xklock 2.7.1 software and earlier versions. This issue specifically affects the Japanese X Keylock implementation, which is designed to provide keyboard lock functionality within X Window System environments. The buffer overflow occurs when the application processes user input without proper bounds checking, creating an exploitable condition that can be leveraged by local attackers to escalate privileges.
The technical flaw manifests in the improper handling of input data within the ja-xklock application's memory management routines. When the program receives input from users, it fails to validate the length of the data being processed against the allocated buffer size. This oversight allows maliciously crafted input to overwrite adjacent memory locations, potentially corrupting the program's execution flow. The vulnerability is particularly dangerous because ja-xklock typically runs with elevated privileges, often as setuid root applications, making successful exploitation directly translate to full system compromise.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it represents a fundamental security weakness in authentication and access control mechanisms. Local attackers who can execute code on the target system can exploit this flaw to gain root access, effectively bypassing all security controls that depend on proper authentication. This vulnerability directly violates the principle of least privilege and can lead to complete system takeover, data exfiltration, and persistent backdoor establishment. The attack vector is relatively simple since it requires only local access and the ability to execute code, making it particularly dangerous in environments where local user access is not strictly controlled.
From a cybersecurity perspective, this vulnerability maps directly to CWE-121, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation'. The vulnerability demonstrates the critical importance of input validation and proper memory management in security-sensitive applications. Organizations should immediately implement patch management procedures to update ja-xklock to versions beyond 2.7.1, while also considering the broader implications for legacy software systems that may contain similar buffer overflow vulnerabilities. Additionally, system administrators should conduct thorough audits of all setuid applications to identify and remediate similar issues, as this vulnerability represents a common class of flaws that continue to plague software systems decades after its initial discovery.