CVE-2012-5378 in ActiveTcl
Summary
by MITRE
Untrusted search path vulnerability in the installation functionality in ActiveTcl 8.5.12, when installed in the top-level C:\ directory, allows local users to gain privileges via a Trojan horse DLL in the C:\TD\bin directory, which is added to the PATH system environment variable, as demonstrated by a Trojan horse wlbsctrl.dll file used by the "IKE and AuthIP IPsec Keying Modules" system service in Windows Vista SP1, Windows Server 2008 SP2, Windows 7 SP1, and Windows 8 Release Preview.
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Analysis
by VulDB Data Team • 08/16/2025
The vulnerability described in CVE-2012-5378 represents a critical untrusted search path weakness in ActiveTcl 8.5.12 installation functionality when deployed in the root C:\ directory. This flaw stems from improper handling of the system PATH environment variable during the installation process, creating a privilege escalation vector that can be exploited by local attackers. The vulnerability specifically manifests when ActiveTcl is installed in the top-level directory structure, where it inadvertently modifies the system PATH to include the C:\TDbin directory, which is subsequently added to the global environment variable.
The technical exploitation of this vulnerability relies on the fundamental principle of DLL hijacking, where malicious code is loaded in place of legitimate system components. When ActiveTcl is installed in C:\, the installer places the TDbin directory in the PATH, creating an opportunity for attackers to place a malicious Trojan horse DLL in this location. The specific demonstration involves the wlbsctrl.dll file, which is utilized by the "IKE and AuthIP IPsec Keying Modules" system service in Windows Vista SP1, Windows Server 2008 SP2, Windows 7 SP1, and Windows 8 Release Preview. This service is particularly significant because it runs with elevated privileges, making any exploitation of the PATH vulnerability potentially lead to system compromise.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass broader system security implications. Attackers can leverage this weakness to execute arbitrary code with the privileges of the targeted service, which typically operates at the system level. The vulnerability affects multiple Windows operating systems, indicating a widespread exposure across the Windows platform ecosystem. This cross-version impact makes the vulnerability particularly dangerous as it can be exploited across different system configurations and deployments, from enterprise servers to desktop environments.
This vulnerability aligns with CWE-427 Uncontrolled Search Path Element, which specifically addresses the issue of programs using untrusted search paths that can be manipulated by attackers to load malicious code. The flaw also maps to ATT&CK technique T1068, which covers Exploitation for Privilege Escalation, as the vulnerability enables local users to gain elevated privileges through improper PATH handling. The PATH manipulation creates a persistent threat vector that can be exploited repeatedly, making it a particularly concerning security weakness. The vulnerability demonstrates poor security practices in software installation processes where environment variables are modified without proper validation or sanitization.
Mitigation strategies for this vulnerability should focus on immediate PATH environment variable sanitization during installation, proper privilege separation, and implementing secure coding practices that prevent untrusted paths from being added to system-wide environment variables. Organizations should conduct immediate vulnerability assessments to identify systems with ActiveTcl installations in the root directory and apply patches or workarounds. The recommended approach includes ensuring that installation processes do not automatically modify system PATH variables, particularly in root directories, and implementing strict controls over which directories are added to the system PATH. Additionally, system administrators should monitor for unauthorized modifications to PATH variables and implement proper access controls to prevent malicious DLL placement in system directories.