CVE-2001-0116 in gpm
Summary
by MITRE
gpm 1.19.3 allows local users to overwrite arbitrary files via a symlink attack.
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Analysis
by VulDB Data Team • 04/30/2019
The vulnerability identified as CVE-2001-0116 affects the gpm package version 1.19.3, which stands for General Purpose Mouse daemon. This daemon is responsible for handling mouse input in Linux console environments and provides a mechanism for applications to access mouse events through the console. The core issue lies in how gpm manages temporary files during its operation, creating a race condition that can be exploited by local users to overwrite arbitrary files on the system. The vulnerability stems from improper file handling procedures within the daemon's execution context, particularly when it creates or modifies temporary files without sufficient security checks.
The technical flaw manifests through a classic symlink attack pattern where an attacker creates symbolic links to target files before gpm attempts to write to them. When gpm executes with elevated privileges to manage console mouse input, it processes these symbolic links without validating their targets, allowing the attacker to redirect file operations to arbitrary locations. This type of vulnerability falls under CWE-377, which addresses insecure temporary file handling, and specifically relates to CWE-59, which covers improper handling of symbolic links. The attack vector requires local system access but can potentially escalate privileges or cause unauthorized file modifications depending on the target files and system configuration.
The operational impact of this vulnerability extends beyond simple file overwriting, as it can be leveraged to compromise system integrity and potentially facilitate further attacks. An attacker could target critical system files such as configuration files, binaries, or log files to gain persistence or execute malicious code. The vulnerability affects systems running gpm version 1.19.3 where the daemon operates with sufficient privileges to modify files, which typically includes root or system-level access. This makes it particularly dangerous in multi-user environments where local users might not have direct access to critical system files but can exploit this weakness to indirectly compromise system security.
Mitigation strategies for CVE-2001-0116 focus on addressing the root cause through proper file handling mechanisms and privilege management. System administrators should immediately upgrade to gpm versions that address this vulnerability, as version 1.19.4 and later implementations corrected the symbolic link handling issues. The recommended approach includes implementing proper file validation before any file operations, using secure temporary file creation methods that prevent symlink attacks, and ensuring that daemon processes run with minimal required privileges. Additionally, the ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically T1068, which involves exploiting weaknesses in the system to gain elevated privileges. Organizations should also implement monitoring for suspicious file creation patterns and consider disabling gpm if console mouse functionality is not required, as this removes the attack surface entirely. Regular security audits of system daemons and their file handling practices remain essential for identifying similar vulnerabilities that could be exploited through similar attack vectors.