CVE-2012-1943 in Firefox
Summary
by MITRE
Untrusted search path vulnerability in Updater.exe in the Windows Updater Service in Mozilla Firefox 12.0, Thunderbird 12.0, and SeaMonkey 2.9 on Windows allows local users to gain privileges via a Trojan horse wsock32.dll file in an application directory.
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Analysis
by VulDB Data Team • 03/25/2021
The vulnerability identified as CVE-2012-1943 represents a critical untrusted search path issue affecting Mozilla Firefox 12.0 Thunderbird 12.0 and SeaMonkey 2.9 on Windows platforms. This flaw specifically impacts the Windows Updater Service component within these applications, creating a privilege escalation vector that adversaries can exploit through carefully crafted malicious files. The vulnerability stems from the insecure handling of dynamic library loading mechanisms during the update process, where the system fails to properly validate the origin and integrity of loaded modules. According to CWE-427, this issue falls under the category of Uncontrolled Search Path Element, which occurs when an application searches for libraries in directories specified by the user or environment without adequate verification of their contents or authenticity.
The technical exploitation of this vulnerability relies on the predictable nature of Windows library loading behavior, where the system searches for required DLL files in a specific order including the current working directory and application directories. When the Updater.exe process executes, it loads the wsock32.dll library from the application directory without proper validation of its source or integrity. An attacker can place a malicious wsock32.dll file in the same directory as the vulnerable application, causing the legitimate Updater.exe process to load and execute the attacker-controlled code with the privileges of the user running the application. This creates a local privilege escalation scenario where a standard user can potentially gain elevated system privileges through this indirect attack vector. The ATT&CK framework categorizes this as privilege escalation through dynamic link library injection, specifically mapping to technique T1055.001 which involves the injection of malicious code into legitimate processes.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass broader security implications for organizations relying on these Mozilla applications. Attackers can leverage this weakness to establish persistent access, escalate privileges to SYSTEM level, or deploy additional malware components through the compromised update mechanism. The vulnerability is particularly concerning because it operates silently within the normal update process, making detection difficult for security monitoring systems. The attack requires minimal user interaction beyond having the vulnerable application installed, and the malicious DLL can remain undetected for extended periods while maintaining persistence. Organizations may face significant risk if multiple users have access to these vulnerable applications, as the attack can be initiated from any user account with local access to the system. The vulnerability also demonstrates the importance of proper application sandboxing and secure coding practices, particularly in update mechanisms where elevated privileges are required for system-level operations.
Mitigation strategies for CVE-2012-1943 should focus on immediate patching of affected applications to version 13.0 or later where the vulnerability has been addressed. System administrators should implement strict access controls and file permissions on application directories to prevent unauthorized DLL injection attempts. The principle of least privilege should be enforced by running applications with minimal required permissions and avoiding execution from directories with write access by untrusted users. Additional protective measures include implementing application whitelisting policies, monitoring for suspicious DLL loading activities, and conducting regular security audits of application directories. Organizations should also consider deploying endpoint protection solutions that can detect and block unauthorized DLL injection attempts. The vulnerability highlights the critical need for secure coding practices in update mechanisms and proper validation of dynamic library loading processes, emphasizing the importance of following secure development lifecycle principles. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other applications and systems.