CVE-2012-1893 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 validate callback parameters during creation of a hook procedure, which allows local users to gain privileges via a crafted application, aka "Win32k Incorrect Type Handling Vulnerability."
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Analysis
by VulDB Data Team • 03/26/2021
The win32k.sys vulnerability represents a critical privilege escalation flaw within Microsoft Windows kernel-mode drivers that affects multiple operating system versions from windows xp through windows 7. This vulnerability resides in the win32k.sys driver which manages user interface components including window management, graphics rendering, and input handling. The flaw specifically manifests during the creation of hook procedures where the kernel-mode driver fails to properly validate callback parameters, creating a dangerous condition that allows local attackers to execute arbitrary code with elevated privileges. The vulnerability is categorized under cwe-121 as a buffer overflow condition that occurs when insufficient validation is performed on data structures passed to kernel-mode functions.
The technical exploitation of this vulnerability leverages the improper handling of callback parameters within the win32k.sys driver during hook procedure creation. When applications attempt to establish hook procedures through the windows api, the driver receives callback function pointers that should be validated before use. However, the driver fails to properly validate these parameters, allowing malicious applications to craft specially crafted callback functions that can be executed with kernel privileges. This type of vulnerability falls under the attack pattern known as privilege escalation through kernel-mode exploitation and aligns with techniques described in the mitre attack framework under privilege escalation tactics. The flaw essentially creates a type confusion scenario where the kernel incorrectly interprets user-supplied data as valid kernel function pointers, enabling attackers to bypass standard security boundaries.
The operational impact of CVE-2012-1893 is severe as it allows local users to escalate their privileges from standard user level to system level without requiring any special authentication or external network access. This means that any user who can run applications on the affected systems can potentially gain complete system control, making it particularly dangerous in multi-user environments or scenarios where users have legitimate access to systems. The vulnerability affects a broad range of microsoft windows versions including xp sp2 and sp3, windows server 2003 sp2, vista sp2, windows server 2008 sp2 and r2, and windows 7 gold and sp1, creating widespread exposure across enterprise networks. The exploitability of this vulnerability makes it a preferred target for malware authors and advanced persistent threat actors seeking to establish persistent system-level access.
Mitigation strategies for this vulnerability include immediate deployment of microsoft security updates that patch the win32k.sys driver to properly validate callback parameters during hook procedure creation. Organizations should prioritize patch management and ensure all systems receive the relevant security updates as soon as they become available. Additional defensive measures include implementing application whitelisting policies to prevent unauthorized applications from running, disabling unnecessary windows services that might be exploited, and monitoring for suspicious hook procedure creation activities through system logs and security information event management systems. The vulnerability demonstrates the importance of kernel-mode security validation and proper input sanitization in preventing privilege escalation attacks, aligning with security best practices outlined in nist cybersecurity framework and iso 27001 standards for secure system development and maintenance.