CVE-2011-1886 in Windows
Summary
by MITRE
win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP3 does not properly validate the arguments to functions, which allows local users to read arbitrary data from kernel memory via a crafted application that triggers a NULL pointer dereference, aka "Win32k Incorrect Parameter Validation Allows Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 11/14/2021
The vulnerability identified as CVE-2011-1886 resides within the win32k.sys kernel-mode driver component of Microsoft Windows XP Service Pack 3, representing a critical information disclosure flaw that stems from improper parameter validation mechanisms. This vulnerability specifically affects the Windows kernel-mode subsystem responsible for managing graphical user interface elements and windowing operations, making it particularly dangerous as it operates at the most privileged level of the operating system. The flaw manifests when the win32k.sys driver fails to adequately validate input parameters passed to its internal functions, creating a pathway for malicious code execution that can result in unauthorized access to sensitive kernel memory regions.
The technical exploitation of this vulnerability occurs through a carefully crafted application that triggers a NULL pointer dereference condition within the win32k.sys driver. When legitimate applications attempt to invoke specific graphics-related functions without proper parameter validation, the driver processes these malformed inputs in a manner that leads to memory access violations. This particular flaw falls under the CWE-252 category of "Unchecked Return Value" and represents a classic example of improper input validation that can be leveraged to extract sensitive information from kernel memory spaces. The vulnerability is classified as a local privilege escalation vector since it requires a user-level application to trigger the condition, but the consequences extend to kernel-level memory access.
The operational impact of CVE-2011-1886 is significant as it enables local attackers to perform arbitrary data reads from kernel memory locations, potentially exposing sensitive system information including cryptographic keys, passwords, and other confidential data stored in memory. This information disclosure capability can serve as a stepping stone for more sophisticated attacks, allowing threat actors to gather intelligence about the target system's configuration and running processes. The vulnerability's exploitation is particularly concerning because it operates within the kernel-mode context where all system protections are effectively bypassed, making it a prime target for attackers seeking to establish persistent access or escalate privileges within the compromised environment.
Mitigation strategies for this vulnerability should focus on immediate patch deployment through Microsoft's security updates, as the manufacturer provided specific fixes for this flaw in their regular security bulletins. System administrators should prioritize applying the relevant Windows security updates that address the win32k.sys validation issues, particularly for systems running Windows XP SP3 which remains vulnerable to this and similar kernel-mode exploits. Additional protective measures include implementing application whitelisting policies to restrict execution of untrusted applications, enabling kernel-mode protection features such as Data Execution Prevention, and conducting regular security assessments to identify potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and credential access, specifically targeting the system's kernel-mode components to achieve unauthorized information disclosure. Organizations should also consider network segmentation and monitoring solutions to detect anomalous behavior that might indicate exploitation attempts, particularly focusing on unusual memory access patterns or kernel-level API calls that could signal the presence of this vulnerability in action.