CVE-2011-1884 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 CVEs listed in MS11-054, aka "Win32k Use After Free Vulnerability."
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Analysis
by VulDB Data Team • 11/14/2021
The CVE-2011-1884 vulnerability represents a critical use-after-free condition 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 interactions with the desktop environment. The flaw specifically manifests in how the driver manages reference counting and object lifecycle within kernel space, creating a scenario where freed memory locations can be accessed and manipulated by malicious code. The vulnerability affects a broad range of Microsoft Windows versions including 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 particularly dangerous due to its widespread impact across multiple operating system families. This vulnerability is classified under CWE-416 as a Use After Free condition, which occurs when a program continues to reference memory after it has been freed, leading to potential exploitation by attackers who can manipulate the freed memory location.
The technical exploitation of this vulnerability requires a local attacker to craft a malicious application that can trigger the improper object management within the win32k.sys driver. The flaw occurs during the handling of windowing objects and graphics operations, where the driver fails to properly validate object references before performing operations on them. When an application creates and destroys windowing objects in a specific sequence, the kernel driver may free memory associated with these objects while still maintaining references to them, creating a window where attackers can overwrite the freed memory with malicious data. This memory corruption can then be leveraged to execute arbitrary code with kernel-level privileges, effectively allowing local users to escalate their access rights from standard user level to system level. The vulnerability is particularly concerning because it operates at kernel level, bypassing traditional user-mode security controls and operating system protections that normally prevent privilege escalation.
The operational impact of CVE-2011-1884 extends beyond simple privilege escalation as it provides attackers with complete control over affected systems. Once exploited, the vulnerability allows for persistent system compromise, enabling attackers to install malware, modify system files, disable security features, and establish backdoors for continued access. The nature of this vulnerability makes it particularly attractive for advanced persistent threat actors who seek to maintain long-term access to compromised systems. Additionally, the vulnerability's presence in multiple Windows versions means that organizations with mixed operating system environments face increased risk, as the exploitation vector remains consistent across different platforms. The vulnerability also demonstrates the complexity of kernel-mode security and the challenges inherent in maintaining secure driver implementations that must handle complex user interaction scenarios while maintaining memory safety. This vulnerability is categorized under ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and specifically relates to 'Exploitation of Windows Admin Shares' and 'Exploitation of Windows Kernel Vulnerabilities'.
Mitigation strategies for CVE-2011-1884 focus primarily on applying Microsoft security patches and updates, as the vulnerability was addressed through the Microsoft Security Bulletin MS11-054. Organizations should ensure that all affected systems receive the appropriate security updates, particularly those running older Windows versions that may not receive extended support. System administrators should also implement additional security measures including disabling unnecessary user interaction with potentially vulnerable applications, monitoring for suspicious kernel-level activity, and maintaining updated intrusion detection systems that can identify exploitation attempts. Network segmentation and least privilege principles should be enforced to limit the potential impact of successful exploitation, while regular security audits should verify that systems remain patched and secure. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates how kernel-level vulnerabilities can provide attackers with the most powerful attack vectors available, emphasizing the need for robust patch management processes and security monitoring across all system components.