CVE-2016-7215 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, Windows 10 Gold, 1511, and 1607, and Windows Server 2016 allow local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 09/30/2022
The CVE-2016-7215 vulnerability 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 operations. This vulnerability resides in the kernel-mode driver subsystem that handles windowing and graphics services, making it particularly dangerous as it operates with the highest privilege level within the operating system. The flaw enables local attackers to execute malicious code with system-level privileges by leveraging a crafted application that exploits improper validation of user-mode input within kernel space.
The technical implementation of this vulnerability stems from inadequate input validation within the win32k.sys driver, which processes windowing and graphics-related system calls from user applications. When a malicious application submits crafted parameters to the driver through specific API calls, the kernel-mode component fails to properly validate these inputs before processing them, creating a condition where attacker-controlled data can influence the execution flow of the driver. This improper validation allows for memory corruption that can be leveraged to execute arbitrary code with kernel privileges, effectively bypassing standard security boundaries between user mode and kernel mode execution environments.
The operational impact of CVE-2016-7215 extends beyond simple privilege escalation, as it provides attackers with complete system compromise capabilities. Once successfully exploited, the vulnerability enables attackers to bypass modern security controls including user access control, code integrity checks, and other kernel-mode protections. The vulnerability affects a broad range of Windows operating systems spanning multiple versions and server editions, making it particularly attractive to attackers seeking widespread exploitation opportunities. The attack vector requires only local system access, meaning that an attacker with limited user privileges can potentially escalate to SYSTEM level access, enabling full control over the affected system.
Security professionals should recognize this vulnerability as a classic example of a kernel-mode privilege escalation flaw, which aligns with CWE-122 (Heap-based Buffer Overflow) and CWE-787 (Out-of-bounds Write) categories. The vulnerability maps to ATT&CK technique T1068 (Local Privilege Escalation) and T1059 (Command and Scripting Interpreter) within the MITRE ATT&CK framework. Organizations should prioritize immediate patch deployment as the primary mitigation strategy, while implementing additional controls such as application whitelisting, kernel-mode driver integrity checking, and monitoring for suspicious kernel-mode activity. Network segmentation and user access controls can help limit the potential impact if exploitation occurs, though the fundamental vulnerability requires official security patches from Microsoft to address the root cause within the win32k.sys driver implementation.