CVE-2016-3308 in Windows
Summary
by MITRE
The kernel-mode drivers 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, 1511, and 1607 allow local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability," a different vulnerability than CVE-2016-3309, CVE-2016-3310, and CVE-2016-3311.
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Analysis
by VulDB Data Team • 09/13/2022
The vulnerability identified as CVE-2016-3308 represents a critical privilege escalation flaw within the Windows kernel-mode drivers, specifically affecting the win32k.sys component that manages user interface elements and graphics rendering. This vulnerability exists in multiple Windows versions including Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012, Windows RT 8.1, and various Windows 10 releases. The flaw allows local attackers with standard user privileges to execute malicious code that can elevate their access level to system-level privileges, effectively bypassing the operating system's security controls. This vulnerability falls under the category of kernel-mode privilege escalation, which is particularly dangerous as it operates at the most privileged level of the operating system.
The technical root cause of CVE-2016-3308 stems from improper input validation within the win32k.sys driver when processing certain graphics-related API calls. Attackers can craft malicious applications that exploit a flaw in how the driver handles specific parameters during user interface operations, particularly those involving graphics rendering and window management functions. The vulnerability creates a condition where untrusted input can trigger a memory corruption issue that allows attackers to manipulate the execution flow of the kernel-mode driver. This type of flaw typically involves buffer overflows, use-after-free conditions, or improper validation of user-supplied data that gets processed by kernel components. The vulnerability is classified as a kernel-mode exploit that leverages the graphics subsystem to achieve privilege escalation, making it particularly insidious as it can be triggered through normal user applications that utilize graphics rendering capabilities.
The operational impact of this vulnerability is severe and far-reaching across enterprise environments, as it provides attackers with a pathway to achieve system-level compromise from a local user position. Once successfully exploited, the vulnerability grants attackers complete control over the affected system, enabling them to install malicious software, modify system configurations, access sensitive data, and potentially establish persistence mechanisms. The vulnerability's exploitation does not require network connectivity or remote access, making it particularly dangerous for organizations where local access might be more prevalent than previously assumed. This privilege escalation vulnerability can be particularly devastating in environments where users have access to systems with elevated privileges or where the system is used in scenarios where local access is common. The vulnerability's presence in multiple Windows versions means that organizations across different deployment scenarios are potentially at risk, including desktop environments, server environments, and mobile platforms.
Microsoft addressed this vulnerability through the release of security updates that patched the input validation flaws in the win32k.sys driver. Organizations should implement these patches immediately and ensure proper testing to avoid potential compatibility issues with existing applications. Security professionals should monitor for exploitation attempts and implement additional security controls including application whitelisting, user access controls, and network segmentation to limit the potential impact of such vulnerabilities. The vulnerability demonstrates the importance of kernel-mode security and highlights the need for comprehensive security testing of system drivers, particularly those handling user input from graphics and user interface components. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of how user interface components can become attack vectors for privilege escalation. The ATT&CK framework categorizes this as privilege escalation through kernel exploitation, where adversaries leverage system-level vulnerabilities to gain elevated privileges. Organizations should conduct thorough vulnerability assessments to identify systems running affected Windows versions and ensure all systems are properly updated with the latest security patches to prevent exploitation of this critical vulnerability.