CVE-2011-0089 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, and R2, and Windows 7 does not properly validate user-mode input, which allows local users to gain privileges via a crafted application, aka "Win32k Window Class Improper Pointer Validation Vulnerability."
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Analysis
by VulDB Data Team • 10/16/2021
The CVE-2011-0089 vulnerability represents a critical privilege escalation flaw within the Windows kernel-mode driver component known as win32k.sys. This vulnerability affects multiple versions of the windows operating system including xp sp2 and sp3, windows server 2003 sp2, windows vista sp1 and sp2, windows server 2008 gold sp2 and r2, and windows 7. The vulnerability stems from improper validation of user-mode input within the kernel-mode drivers that handle windowing operations and graphics rendering. The affected win32k.sys driver is responsible for managing window class registration and window management functions that are fundamental to the graphical user interface operations in windows operating systems. This particular flaw manifests as a pointer validation issue that occurs when the driver processes user-mode input through window class registration mechanisms.
The technical exploitation of this vulnerability occurs when a local attacker crafts a malicious application that triggers improper pointer validation within the win32k.sys driver. The vulnerability specifically relates to how the driver handles window class registration operations and fails to properly validate pointers that are passed from user-mode applications to kernel-mode code. When a malicious application attempts to register a window class with crafted parameters, the win32k.sys driver does not adequately validate the pointer references, potentially allowing an attacker to manipulate kernel memory structures. This improper validation creates a condition where attacker-controlled data can influence the execution flow of kernel-mode code, leading to privilege escalation. The vulnerability falls under the common weakness enumeration category of cwe-125 out of bounds read and cwe-787 out of bounds write, both of which are classified as memory safety issues that can lead to arbitrary code execution.
The operational impact of this vulnerability is significant as it allows local users to escalate their privileges from standard user level to system level execution. This privilege escalation capability means that an attacker who has already gained access to a user account can leverage this vulnerability to gain full system control without requiring additional authentication or exploitation methods. The vulnerability affects all versions of windows that were released prior to the patching of this specific issue, making it a widespread concern across enterprise environments. The attack vector requires only local access to the target system, which makes it particularly dangerous as it can be exploited by malware that gains initial access through other means such as phishing attacks or social engineering. The vulnerability also aligns with the attack technique known as privilege escalation through kernel-mode exploitation and can be categorized under the attack pattern of code injection into kernel space.
Mitigation strategies for CVE-2011-0089 include immediate deployment of microsoft security patches that address the pointer validation flaw in win32k.sys driver. organizations should ensure that all affected windows systems are updated with the relevant security updates released by microsoft, particularly the ms11-006 security bulletin that specifically addresses this vulnerability. additional protective measures include implementing application whitelisting policies to prevent execution of unauthorized applications, enabling user access control features, and monitoring for suspicious window class registration activities. the vulnerability also highlights the importance of secure coding practices in kernel-mode drivers and demonstrates the critical need for proper input validation and pointer handling in operating system components. network administrators should consider implementing monitoring solutions that can detect anomalous windowing operations that might indicate exploitation attempts, while also ensuring that systems are configured to automatically apply security updates to minimize exposure windows. organizations should also consider the broader implications of kernel-mode vulnerabilities and implement layered security approaches that include both endpoint protection and network monitoring to detect and prevent exploitation of similar vulnerabilities.