CVE-2016-0095 in Windows
Summary
by MITRE
The kernel-mode driver in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 allows local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability," a different vulnerability than CVE-2016-0093, CVE-2016-0094, and CVE-2016-0096.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/09/2022
The vulnerability identified as CVE-2016-0095 represents a critical privilege escalation flaw within the Windows kernel-mode driver subsystem, specifically affecting multiple versions of the Windows operating system from Vista through Windows 10. This vulnerability resides in the win32k.sys driver which manages user interface components and graphics rendering functions within the Windows kernel. The flaw allows local attackers with standard user privileges to execute malicious code that can elevate their privileges to system level, effectively bypassing the operating system's security model. The vulnerability is categorized under CWE-264, which addresses permissions, privileges, and access controls, specifically targeting the improper handling of kernel-mode privileges.
The technical exploitation of this vulnerability occurs through a crafted application that leverages memory corruption within the win32k.sys driver. Attackers can manipulate the graphics subsystem through the User-Mode Driver Framework (UMDF) to trigger a buffer overflow or use-after-free condition that results in arbitrary code execution with kernel privileges. The flaw stems from insufficient validation of user-supplied data passed to kernel-mode functions, allowing attackers to craft malicious inputs that corrupt kernel memory structures. This vulnerability is particularly concerning because it operates within the kernel space where all security boundaries are effectively bypassed, enabling attackers to perform actions such as disabling security features, modifying system files, or establishing persistent backdoors.
The operational impact of CVE-2016-0095 extends beyond simple privilege escalation, as it provides attackers with complete system compromise capabilities that align with ATT&CK technique T1068, which covers local privilege escalation through kernel exploits. Once elevated to kernel level, attackers can manipulate the entire system state, access encrypted data, modify registry entries, and establish persistence mechanisms that survive system reboots. The vulnerability affects a broad range of Windows versions, making it particularly dangerous for organizations with mixed operating system environments, and the exploitation can occur without requiring network connectivity, making detection more challenging. Organizations that have not applied the relevant security patches are vulnerable to attacks that can lead to complete system compromise and potential data breaches.
Microsoft addressed this vulnerability through the release of security updates in their regular patch cycle, requiring system administrators to apply the appropriate patches to remediate the issue. The recommended mitigation strategy involves immediate deployment of the Windows security updates, combined with network monitoring to detect potential exploitation attempts. Additionally, organizations should implement defense-in-depth strategies including user account control restrictions, application whitelisting, and regular security assessments to reduce the attack surface. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates how kernel-level flaws can provide attackers with the most privileged access possible within a Windows environment, making timely patch management critical for maintaining system integrity and security posture.