CVE-2000-0340 in Linux
Summary
by MITRE
Buffer overflow in Gnomelib in SuSE Linux 6.3 allows local users to execute arbitrary commands via the DISPLAY environmental variable.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2000-0340 represents a critical buffer overflow flaw within the Gnomelib component of SuSE Linux 6.3 operating system. This issue resides in the handling of the DISPLAY environment variable, which is fundamental to X Window System operations and graphical user interfaces. The flaw manifests when the system processes user-supplied input through the DISPLAY variable, creating an exploitable condition that can be leveraged by local attackers to gain elevated privileges and execute arbitrary code on the affected system.
The technical implementation of this vulnerability stems from improper bounds checking within the Gnomelib library functions that process the DISPLAY environment variable. When a local user manipulates this variable with malicious input exceeding the allocated buffer size, memory corruption occurs that can be exploited to overwrite adjacent memory locations including return addresses and function pointers. This buffer overflow condition directly maps to CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory regions. The vulnerability specifically affects the X11 display management functionality and demonstrates how environment variable handling can create exploitable conditions in system libraries.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides local attackers with complete control over the affected system. Since the flaw exists within a core system library that many applications depend upon, successful exploitation can result in unauthorized code execution with the privileges of the targeted process. Attackers can leverage this condition to install backdoors, modify system files, or establish persistent access to the compromised host. The local nature of the attack means that any user with access to the system can potentially exploit this vulnerability without requiring network connectivity or specialized tools, making it particularly dangerous in multi-user environments where privilege separation is critical.
Mitigation strategies for CVE-2000-0340 should focus on immediate system updates and security hardening measures. The primary solution involves applying the vendor-supplied patches that address the buffer overflow in Gnomelib and ensure proper bounds checking for environment variable processing. System administrators should also implement strict environment variable validation and sanitize all user inputs before processing them through system libraries. Additional protective measures include disabling unnecessary graphical services, implementing proper access controls, and monitoring for suspicious environment variable modifications. From an ATT&CK framework perspective, this vulnerability aligns with T1068 which covers 'Exploitation for Privilege Escalation' and T1059 which covers 'Command and Scripting Interpreter' as attackers can leverage the privilege escalation to execute arbitrary commands through the compromised system. Organizations should also consider implementing runtime protections such as stack canaries and address space layout randomization to make exploitation more difficult. Regular security audits and vulnerability assessments should be conducted to identify similar issues in legacy system components that may not have received adequate security updates over time.