CVE-2000-0531 in Linux
Summary
by MITRE
Linux gpm program allows local users to cause a denial of service by flooding the /dev/gpmctl device with STREAM sockets.
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Analysis
by VulDB Data Team • 11/09/2024
The vulnerability described in CVE-2000-0531 represents a classic denial of service flaw within the Linux gpm (General Purpose Mouse) program which serves as a mouse driver for console environments. This issue specifically affects systems running Linux distributions where gpm is installed and actively managing mouse input through the /dev/gpmctl device interface. The gpm program operates as a daemon that handles mouse events in text mode terminals, making it a critical component for console-based user interaction. When local users exploit this vulnerability, they can flood the device with STREAM sockets, effectively overwhelming the system's ability to process legitimate mouse input and causing the service to become unresponsive or crash entirely. This particular weakness demonstrates how kernel-level device interfaces can be manipulated to disrupt system functionality, particularly in environments where console mouse support is essential.
The technical flaw stems from inadequate input validation and resource management within the gpm program's handling of STREAM socket connections to the /dev/gpmctl device. STREAM sockets represent a type of inter-process communication mechanism that allows for reliable data transmission between processes. When local users send excessive STREAM socket requests to the gpm control device, the program fails to properly throttle or limit incoming connections, leading to resource exhaustion. This behavior aligns with common software security weaknesses such as those categorized under CWE-400, which addresses "Uncontrolled Resource Consumption" or "Resource Exhaustion" vulnerabilities. The vulnerability specifically impacts the program's ability to maintain proper state management and connection handling, as evidenced by the failure to properly close or limit socket connections, creating a scenario where legitimate system operations cannot proceed normally.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromising the usability of console environments where gpm is essential for mouse functionality. In multi-user systems or environments where console access is critical for system administration, such as server environments or embedded systems, this denial of service condition can severely impact operational continuity. Users attempting to perform administrative tasks through console interfaces would find their mouse input ignored or the system unresponsive, forcing them to potentially reboot or restart the gpm service manually. This vulnerability particularly affects systems where the console mouse interface is the primary means of interaction, making it a significant concern for system administrators who rely on console-based access for critical operations. The local nature of the exploit means that any user with access to the system can potentially trigger the denial of service, making it a particularly dangerous weakness in multi-user environments.
Mitigation strategies for this vulnerability should focus on implementing proper resource management and connection limiting within the gpm program. System administrators should ensure that the gpm service is properly configured to limit the number of concurrent connections and implement appropriate timeout mechanisms for socket handling. The most effective approach involves upgrading to patched versions of gpm that include proper input validation and resource management controls. Additionally, implementing proper access controls and monitoring for unusual connection patterns can help detect potential exploitation attempts. From a security framework perspective, this vulnerability demonstrates the importance of applying the principle of least privilege and proper resource management as outlined in various cybersecurity standards. Organizations should consider implementing network segmentation and access controls to limit local user access to critical system components, while also ensuring regular security updates and patches are applied to prevent exploitation of known vulnerabilities. The ATT&CK framework would categorize this as a privilege escalation or denial of service technique, as it allows local users to disrupt system services and potentially gain unauthorized control over system resources through manipulation of device interfaces.