CVE-2016-3219 in Windows
Summary
by MITRE
The kernel-mode driver in Microsoft Windows 10 Gold and 1511 allows local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 05/31/2025
The vulnerability identified as CVE-2016-3219 represents a critical privilege escalation flaw within the Windows kernel-mode driver subsystem, specifically affecting Windows 10 Gold and version 1511 releases. This vulnerability resides in the win32k.sys driver which manages user-mode graphics components and handles windowing system operations. The flaw enables 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 boundaries.
The technical mechanism underlying this vulnerability involves improper validation of user-mode input within the kernel-mode driver context. When applications interact with the graphics subsystem through win32k.sys, the driver fails to properly sanitize or validate certain parameters passed from user space. This validation gap creates an opportunity for attackers to craft specifically designed applications that manipulate the driver's behavior through crafted inputs. The vulnerability manifests when the driver processes graphics-related API calls that involve window management operations, particularly those related to window positioning, sizing, or rendering parameters. The flaw is classified as a use-after-free condition or buffer overflow scenario where attacker-controlled data can overwrite critical kernel memory structures, allowing arbitrary code execution in kernel context with system-level privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete system control capabilities. Once elevated to kernel level, malicious actors can bypass all Windows security mechanisms including user access control, file system protections, and process isolation features. This vulnerability directly relates to CWE-121 which describes heap-based buffer overflow conditions, and CWE-122 which addresses stack-based buffer overflow scenarios. The attack vector requires local system access and typically involves a user executing a specially crafted application, making it particularly dangerous in environments where users have elevated privileges or where social engineering attacks can be employed to trick users into running malicious code. The vulnerability's exploitation does not require network connectivity, making it particularly stealthy and difficult to detect through traditional network monitoring approaches.
Microsoft addressed this vulnerability through a comprehensive patch release that corrected the input validation mechanisms within the win32k.sys driver. The fix involved implementing stricter parameter validation and memory management controls to prevent malicious input from corrupting kernel memory structures. Organizations should prioritize immediate deployment of the relevant security updates and maintain comprehensive monitoring for any suspicious system behavior that might indicate exploitation attempts. Security teams should also implement additional defensive measures including process monitoring for suspicious kernel-mode activities, network intrusion detection system rules to identify potential exploitation patterns, and regular security assessments to ensure proper patch management across all affected Windows 10 installations. The vulnerability demonstrates the critical importance of kernel-mode security and highlights how flaws in system-level components can provide attackers with complete system compromise capabilities, aligning with ATT&CK technique T1068 which describes local privilege escalation through kernel exploits.