CVE-2012-0157 in Windows
Summary
by MITRE
win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 does not properly handle window messaging, which allows local users to gain privileges via a crafted application that calls the PostMessage function, aka "PostMessage Function Vulnerability."
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/05/2025
The CVE-2012-0157 vulnerability represents a critical privilege escalation flaw within the Windows kernel-mode driver subsystem, specifically affecting the win32k.sys component that handles window messaging operations. This vulnerability exists in multiple Windows operating systems including XP SP2/SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2/R2/R2 SP1, and Windows 7 Gold/SP1, making it one of the most widespread kernel-mode privilege escalation vulnerabilities of its time. The flaw stems from improper handling of window messaging operations within the kernel, particularly when applications utilize the PostMessage function to send messages between windows.
The technical exploitation of this vulnerability occurs through a local privilege escalation attack vector where a malicious application can craft specific window messages that trigger memory corruption within the win32k.sys driver. When the kernel processes these crafted PostMessage calls, it fails to properly validate the message parameters or handle the messaging context, leading to memory corruption that can be leveraged to execute arbitrary code with kernel-level privileges. This represents a classic kernel-mode buffer overflow or memory corruption vulnerability that allows local users to escalate their privileges from user-level to SYSTEM level access. The vulnerability specifically relates to how the kernel handles window message queues and message processing, where improper bounds checking or parameter validation occurs during the message dispatching process.
From an operational impact perspective, this vulnerability poses significant security risks as it enables local attackers to gain SYSTEM-level privileges without requiring network access or external exploitation vectors. The attack requires only local system access and the ability to run a malicious application, making it particularly dangerous in environments where users may have local access to systems but should not possess administrative privileges. Once exploited, the attacker gains complete control over the target system, enabling them to read/write any file, modify system configurations, install malware, or establish persistent backdoors. This vulnerability has been extensively documented in various exploit kits and malware samples, demonstrating its practical utility for attackers seeking to escalate privileges on compromised systems. The impact extends beyond individual system compromise to potentially enable broader network infiltration and lateral movement within compromised environments.
Mitigation strategies for CVE-2012-0157 primarily focus on immediate patching of affected systems through Microsoft security updates, as this vulnerability was addressed through the Microsoft Security Bulletin MS12-002 released in January 2012. Organizations should implement comprehensive patch management procedures to ensure all affected Windows systems receive the necessary updates promptly. Additional mitigations include implementing application whitelisting policies, restricting local user privileges, disabling unnecessary services, and monitoring for suspicious PostMessage activity in system logs. Security professionals should also consider implementing intrusion detection systems that can identify potential exploitation attempts through anomalous window messaging patterns. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of how kernel-mode vulnerabilities can be exploited for privilege escalation, falling under ATT&CK technique T1068 for Local Privilege Escalation. Organizations should also consider implementing security awareness training to prevent users from executing untrusted applications that could exploit this vulnerability.