CVE-2011-0087 in Windows
Summary
by MITRE
win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Server 2003 SP2, Vista SP1 and SP2, and Server 2008 Gold and SP2 does not properly validate user-mode input, which allows local users to gain privileges via a crafted application, aka "Win32k Insufficient User Input Validation Vulnerability."
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Analysis
by VulDB Data Team • 10/16/2021
The CVE-2011-0087 vulnerability represents a critical privilege escalation flaw within the Windows kernel-mode driver subsystem, specifically affecting the win32k.sys component that handles user interface processing. This vulnerability exists in multiple Windows operating systems including Windows xp service pack 2 and 3, server 2003 service pack 2, vista service pack 1 and 2, and server 2008 gold and service pack 2. The flaw stems from insufficient validation of user-mode input within kernel-mode drivers, creating a pathway for malicious applications to execute arbitrary code with elevated privileges. The vulnerability is categorized under CWE-125 as an out-of-bounds read condition, which allows attackers to manipulate memory structures through improper input validation mechanisms.
The technical exploitation of this vulnerability occurs when a local attacker crafts a malicious application that triggers improper validation of user-mode input within the win32k.sys driver. This driver is responsible for processing user interface elements such as windows, menus, and graphics operations, making it a prime target for privilege escalation attacks. The vulnerability specifically affects the kernel-mode driver's handling of user input, where insufficient bounds checking allows attackers to corrupt memory structures and potentially execute arbitrary code with system-level privileges. The flaw is classified under the ATT&CK technique T1068 which describes the use of local privilege escalation techniques to gain elevated system access.
The operational impact of CVE-2011-0087 is significant as it enables local users to escalate their privileges from standard user level to system administrator level without requiring external network access. This makes the vulnerability particularly dangerous in environments where multiple users share systems or where attackers have already gained initial access through other means. The vulnerability affects a wide range of Windows operating systems, making it a substantial threat across enterprise environments. Attackers can leverage this flaw to establish persistent access, install backdoors, or escalate their privileges to perform unauthorized system modifications. The exploitation requires local access to the target system but does not require network connectivity, making it harder to detect through traditional network-based monitoring systems.
Mitigation strategies for CVE-2011-0087 focus on applying Microsoft security patches and implementing additional security controls to reduce the attack surface. Organizations should immediately deploy the security updates released by Microsoft to address this vulnerability, as the patch resolves the insufficient input validation issue in the win32k.sys driver. Additional mitigations include implementing user access controls, disabling unnecessary user accounts, and monitoring for suspicious process activity that might indicate exploitation attempts. System administrators should also consider implementing application whitelisting policies and monitoring for abnormal privilege escalation events. The vulnerability's classification as a kernel-mode flaw makes it particularly important to maintain up-to-date security patches and implement comprehensive system hardening measures to prevent exploitation. Organizations should also consider network segmentation and monitoring to detect potential exploitation attempts, as the vulnerability requires local system access to exploit.