CVE-2010-4000 in gnome-shell
Summary
by MITRE
gnome-shell in GNOME Shell 2.31.5 places a zero-length directory name in the LD_LIBRARY_PATH, which allows local users to gain privileges via a Trojan horse shared library in the current working directory.
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Analysis
by VulDB Data Team • 02/08/2019
The vulnerability identified as CVE-2010-4000 affects GNOME Shell version 2.31.5 and represents a privilege escalation flaw that exploits how the system handles library loading paths. This issue occurs when the gnome-shell application incorrectly processes the LD_LIBRARY_PATH environment variable by including a zero-length directory name, creating an exploitable condition that can be leveraged by local attackers. The vulnerability stems from improper handling of environment variables during application execution, specifically within the dynamic library loading mechanism that GNOME Shell employs to locate required shared libraries.
The technical flaw manifests through the manipulation of the LD_LIBRARY_PATH variable where a zero-length directory component is inadvertently included in the search path. When a user executes gnome-shell, the application processes this malformed library path which can cause the system to search for shared libraries in the current working directory before checking standard system locations. This behavior creates an opportunity for attackers to place malicious shared libraries in directories where they can be loaded by the privileged gnome-shell process, effectively enabling privilege escalation from a regular user account to a root-level privileged process.
The operational impact of this vulnerability extends beyond simple privilege escalation as it allows attackers to execute arbitrary code with elevated privileges on systems running affected GNOME Shell versions. The attack vector requires local access to the system since the exploit relies on placing malicious libraries in the current working directory, making it particularly dangerous in environments where users may have access to shell sessions or desktop environments. This vulnerability directly violates security principles by allowing unauthorized code execution with elevated privileges, potentially enabling complete system compromise.
Mitigation strategies for CVE-2010-4000 involve immediate patching of affected GNOME Shell installations to version 2.32.0 or later where the issue has been resolved through proper handling of the LD_LIBRARY_PATH environment variable. System administrators should also implement proper file system permissions and audit current working directories for unauthorized shared library placements. The vulnerability aligns with CWE-276, which addresses improper privilege management, and maps to ATT&CK technique T1068, privilege escalation through dynamic link library injection. Organizations should also consider implementing additional security controls such as monitoring for suspicious library loading patterns and restricting the ability to modify critical system directories. Regular security assessments and vulnerability scanning should be conducted to identify other potential environment variable manipulation issues that could lead to similar privilege escalation vulnerabilities in other applications.