CVE-2011-1237 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 • 11/02/2021
The CVE-2011-1237 vulnerability represents a critical use-after-free condition in the win32k.sys kernel-mode driver component of Microsoft Windows operating systems. This vulnerability specifically affects 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. The flaw resides in the kernel-mode drivers that handle graphical user interface operations, making it particularly dangerous as it operates at the most privileged level of the operating system. The vulnerability stems from improper management of driver objects within the win32k.sys module, which is responsible for handling windowing system operations and graphical rendering components.
The technical exploitation of this vulnerability occurs when a malicious application crafts a specific sequence of operations that triggers the improper memory management within the win32k.sys driver. During normal operation, the driver maintains references to kernel-mode objects that are eventually freed when no longer needed. However, in this case, the driver continues to reference memory locations that have already been deallocated, creating a use-after-free condition. This condition allows an attacker to manipulate the freed memory and potentially execute arbitrary code with kernel-level privileges. The vulnerability is classified under CWE-416 as a use-after-free error, which represents a well-known class of memory safety issues that can lead to privilege escalation attacks.
The operational impact of CVE-2011-1237 is severe as it provides local attackers with a pathway to achieve privilege escalation from standard user level to kernel-level privileges. This means that any user who can run a malicious application on an affected system can potentially gain complete system control, including the ability to install malware, modify system files, access sensitive data, and disable security features. The vulnerability's exploitation requires local access, making it less likely to be exploited remotely, but still poses significant risk in environments where users may have elevated privileges or where privilege escalation attacks are part of broader compromise strategies. The attack vector specifically involves crafting a malicious application that can manipulate the win32k.sys driver object management, leveraging the inherent memory management flaws to execute code with system-level privileges.
Microsoft addressed this vulnerability through security update MS11-034, which specifically targeted the win32k.sys use-after-free issue. Organizations should implement this patch immediately and maintain comprehensive monitoring for any signs of exploitation attempts. System administrators should also consider implementing additional security controls such as user access restrictions, application whitelisting, and enhanced endpoint protection measures to mitigate potential exploitation attempts. The vulnerability demonstrates the critical importance of kernel-mode driver security and proper memory management practices, as these components form the foundation of operating system security and can provide attackers with the most powerful attack vectors available. Security professionals should note that this vulnerability represents a classic example of how improper object lifetime management in kernel drivers can lead to severe privilege escalation exploits, aligning with common attack patterns documented in the MITRE ATT&CK framework under privilege escalation techniques.