CVE-2011-0671 in Windows
Summary
by MITRE
Use-after-free vulnerability in 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 leverages incorrect driver object management, a different vulnerability than other "Vulnerability Type 1" CVEs listed in MS11-034, aka "Win32k Use After Free Vulnerability."
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Analysis
by VulDB Data Team • 04/26/2025
The CVE-2011-0671 vulnerability represents a critical use-after-free flaw in the win32k.sys kernel-mode driver component of Microsoft Windows operating systems. This vulnerability exists within the windowing subsystem that manages graphical user interface elements and handles user input processing. The flaw specifically manifests in how the driver object management operates during the handling of user-mode applications that interact with the kernel-mode components through the win32k.sys driver. This particular vulnerability is classified under CWE-416 as a use-after-free condition, where memory that has been freed is subsequently accessed, creating potential for arbitrary code execution. The vulnerability affects a wide range of Windows versions including Windows xp sp2 and sp3, windows server 2003 sp2, windows vista sp1 and sp2, windows server 2008 gold and sp2, windows server 2008 r2 and r2 sp1, and windows 7 gold and sp1, making it one of the most widespread kernel-mode vulnerabilities of its time.
The technical exploitation of this vulnerability occurs when a malicious application crafted to manipulate driver object references triggers a race condition in the win32k.sys driver. During normal operation, the driver maintains references to kernel objects that represent user interface elements such as windows, menus, and other graphical components. When an application improperly manages these references or when the driver fails to properly validate object states, it creates a scenario where freed memory can be reallocated and subsequently accessed by an attacker-controlled application. This particular vulnerability differs from other "vulnerability type 1" issues referenced in ms11-034 because it specifically targets the kernel-mode driver object management rather than other aspects of the windows kernel. The flaw allows local attackers to escalate privileges from user-level to kernel-level execution context, effectively providing complete system compromise capabilities. The vulnerability operates through the windowing subsystem's object management routines where improper reference counting and memory deallocation lead to the use-after-free condition.
The operational impact of CVE-2011-0671 is severe and directly aligns with the attack pattern described in the mitre att&ck framework under privilege escalation techniques. Once successfully exploited, this vulnerability enables attackers to gain kernel-level privileges, which provides complete control over the affected system. The attack vector requires local system access, making it particularly dangerous in environments where users have legitimate access to systems but could be compromised through social engineering or other means. The vulnerability's exploitation can result in persistent backdoor installation, data exfiltration, system monitoring, and complete compromise of the target environment. The widespread nature of affected operating systems means that organizations running these versions face significant risk exposure, with the potential for lateral movement within networks if attackers establish footholds on multiple systems. This vulnerability was particularly concerning because it allowed for privilege escalation without requiring special privileges or network access, making it an attractive target for attackers seeking persistent access to systems.
Mitigation strategies for CVE-2011-0671 primarily focus on the immediate application of microsoft security patches released as part of ms11-034. Organizations should prioritize deployment of the relevant security updates across all affected windows systems to remediate the vulnerability at the source. Additional defensive measures include implementing application whitelisting policies to prevent unauthorized applications from executing and monitoring for suspicious kernel-mode activity that might indicate exploitation attempts. The vulnerability's classification as a use-after-free condition makes it particularly susceptible to exploitation through heap spraying techniques, where attackers attempt to control memory layout to ensure successful exploitation. System administrators should also consider implementing enhanced monitoring for kernel-mode driver activity and establishing baseline behavioral patterns to detect anomalous system behavior that might indicate exploitation attempts. Given the vulnerability's nature, organizations should conduct thorough security assessments to identify systems running affected versions of windows and prioritize patch deployment to mitigate the risk of exploitation. The vulnerability's impact on system integrity and privilege escalation capabilities makes it essential that organizations treat this as a critical security concern requiring immediate attention and remediation.