CVE-2011-1226 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 SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows local users to gain privileges via a crafted application that triggers a NULL pointer dereference, a different vulnerability than other "Vulnerability Type 2" CVEs listed in MS11-034, aka "Win32k Null Pointer De-reference Vulnerability."
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Analysis
by VulDB Data Team • 01/18/2025
The vulnerability identified as CVE-2011-1226 represents a critical privilege escalation flaw within the Windows kernel-mode driver subsystem, specifically affecting the win32k.sys component that handles user interface operations and graphics rendering. This vulnerability resides in the Windows operating system's kernel-mode drivers, making it particularly dangerous as it operates at the highest privilege level within the system. The flaw manifests when a malicious application triggers a NULL pointer dereference condition within the win32k.sys driver, which is responsible for managing windowing system components including graphics device interface operations and user input handling. This particular vulnerability is classified as a type 2 vulnerability according to Microsoft's classification system, distinguishing it from other related issues such as those detailed in MS11-034, and specifically targets the kernel-mode graphics subsystem that interfaces directly with the hardware rendering capabilities of Windows systems.
The technical exploitation of this vulnerability occurs through a carefully crafted application that can manipulate the win32k.sys driver into attempting to access a NULL memory pointer during normal operation. When this occurs, the kernel-mode driver fails to properly validate memory references, leading to a system crash or more critically, allowing a local attacker to escalate privileges to SYSTEM level access. The NULL pointer dereference vulnerability stems from inadequate input validation within the kernel-mode driver code, where the driver fails to properly check if memory pointers are valid before attempting to dereference them. This particular flaw affects a broad range of Windows operating systems including Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, as well as Windows 7 Gold and SP1, making it one of the most widely impacted vulnerabilities of its kind. The vulnerability operates under the Common Weakness Enumeration CWE-476 which specifically addresses NULL pointer dereference conditions in software systems.
The operational impact of this vulnerability extends beyond simple system instability, as successful exploitation can result in complete system compromise and privilege escalation to the highest system level. Local attackers who can execute code on the target system can leverage this flaw to gain SYSTEM privileges, effectively providing them with unrestricted access to all system resources, files, and user data. The attack vector requires local execution capability since the vulnerability is designed to be exploited by applications running in the same security context as the target system, making it particularly concerning for environments where untrusted applications might be executed. This vulnerability aligns with the MITRE ATT&CK framework under the privilege escalation technique category, specifically targeting the 'Windows Admin Rights' and 'System Services' attack paths that adversaries use to gain elevated privileges. The vulnerability's impact is amplified by the fact that it affects multiple versions of Windows operating systems, creating a widespread attack surface that spans over a decade of Windows releases, and represents a classic example of a kernel-mode vulnerability that can completely bypass user-mode security controls.
Mitigation strategies for CVE-2011-1226 require immediate implementation of Microsoft security patches and updates, as the primary fix involves applying the relevant security updates that address the NULL pointer dereference condition in the win32k.sys driver. System administrators should prioritize patching all affected Windows systems, particularly those running older versions of Windows that remain in production environments. Additionally, implementing security configurations such as disabling unnecessary user interface components and limiting local application execution can reduce the attack surface. The vulnerability also highlights the importance of maintaining up-to-date security patches and implementing proper system hardening measures to prevent exploitation of kernel-mode vulnerabilities. Organizations should also consider implementing application whitelisting policies and monitoring for suspicious system behavior that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of kernel-mode security and the potential consequences when memory management validation fails in core operating system components, making it essential for security teams to maintain comprehensive patch management processes and monitor for similar vulnerabilities in other system drivers.