CVE-2011-0676 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 • 01/21/2025
The vulnerability identified as CVE-2011-0676 represents a critical privilege escalation flaw within the Windows kernel-mode driver component known as win32k.sys. This vulnerability affects multiple versions of Microsoft Windows including XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 in various service pack configurations, and Windows 7 Gold and SP1. The flaw specifically resides in the kernel-mode drivers that manage user interface components and graphics rendering functions, making it particularly dangerous as it operates at the most privileged level of the operating system. The vulnerability is classified under CWE-476 which specifically addresses NULL pointer dereference conditions in software development, where a program attempts to access memory through a null pointer reference, leading to system instability and potential privilege escalation.
The technical mechanism of exploitation involves a local attacker crafting a malicious application that triggers a specific code path within win32k.sys where a NULL pointer dereference occurs. When the kernel-mode driver encounters this condition during processing of user interface operations, the system crashes and potentially allows an attacker to execute code with elevated privileges. This particular vulnerability differs from other "Vulnerability Type 2" issues referenced in MS11-034, indicating it represents a distinct code path and exploitation vector. The flaw essentially allows a local user to bypass normal security restrictions and escalate their privileges to SYSTEM level access, which provides complete control over the affected system. This represents a classic kernel-mode privilege escalation vulnerability that leverages the inherent trust relationships between kernel components and user applications.
The operational impact of CVE-2011-0676 is severe as it enables local privilege escalation attacks that can be exploited by any user account on the system, regardless of their initial access level. Once successfully exploited, attackers can gain SYSTEM-level privileges, which provides complete control over the operating system, including the ability to install malicious software, modify system files, access all user data, and potentially establish persistence mechanisms. This vulnerability is particularly concerning because it operates at the kernel level, making it extremely difficult to detect and prevent through traditional endpoint protection mechanisms. The exploitation requires local access to the target system, but this access can be obtained through various means including social engineering, phishing attacks, or initial compromise through other vulnerabilities, making the attack surface quite broad within enterprise environments. The vulnerability demonstrates how kernel-level flaws can provide attackers with the ultimate leverage for system compromise and persistence.
Mitigation strategies for CVE-2011-0676 primarily focus on applying the official Microsoft security patches released as part of MS11-034. Organizations should prioritize immediate deployment of the relevant security updates across all affected Windows systems to prevent exploitation. Additionally, implementing application whitelisting policies and restricting local user privileges can help reduce the attack surface and limit potential damage from successful exploitation attempts. System administrators should also monitor for unusual system behavior or kernel-mode crashes that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1068 which covers privilege escalation through kernel exploits, and T1059 which addresses execution through legitimate system utilities. Network segmentation and privileged access management controls should be strengthened to minimize the potential impact if exploitation occurs. Regular security assessments and vulnerability scanning should include verification of patch status for this specific vulnerability to ensure comprehensive protection across the enterprise infrastructure.