CVE-2016-7259 in Windows
Summary
by MITRE
The Graphics Component in 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 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 • 10/08/2022
The vulnerability identified as CVE-2016-7259 represents a critical privilege escalation flaw within the Windows kernel-mode graphics component known as Win32k.sys. This issue affects multiple Windows operating systems including Vista, Server 2008, 7, 8.1, RT 8.1, Windows 10 versions, and Server 2016, creating a widespread attack surface across the Windows ecosystem. The vulnerability resides in the kernel-mode drivers responsible for graphics processing and user interface rendering, specifically within the graphics subsystem that handles windowing operations and graphical user interface components. The flaw enables local attackers with standard user privileges to execute malicious code that can elevate their privileges to system level, effectively bypassing the security boundaries that normally protect the operating system from unauthorized access.
The technical root cause of this vulnerability stems from improper input validation within the graphics component's handling of user-mode applications that interact with kernel-mode drivers through the Win32k.sys interface. This vulnerability is classified as a kernel-mode privilege escalation issue that allows attackers to manipulate graphics-related data structures and function calls to achieve unauthorized system-level access. The flaw manifests when the graphics subsystem processes crafted graphical objects or API calls that trigger memory corruption in kernel space, specifically within the graphics driver's memory management routines. According to CWE classification, this represents a weakness in the input validation of kernel-mode components, specifically CWE-121, which deals with stack-based buffer overflows, and CWE-125, which addresses out-of-bounds read conditions. The vulnerability operates through the Windows kernel's graphics subsystem and leverages the inherent trust relationship between user-mode applications and kernel-mode drivers, creating an attack vector that can be exploited without requiring network connectivity or specialized hardware access.
The operational impact of CVE-2016-7259 is severe and far-reaching, as it provides attackers with a reliable method to escalate privileges from standard user accounts to SYSTEM level access. This privilege escalation capability allows adversaries to bypass standard security controls including User Account Control, file system permissions, and registry access restrictions that normally protect system integrity. Once successfully exploited, attackers can install persistent backdoors, modify system files, disable security software, and access sensitive data without detection. The vulnerability's exploitation typically requires a local attacker who can run a malicious application on the target system, making it particularly dangerous in environments where users have the ability to execute arbitrary code or where social engineering attacks can be employed to gain initial access. The attack surface is particularly concerning given that this vulnerability affects such a broad range of Windows versions, from older systems like Vista to newer releases including Windows 10, meaning organizations across multiple generations of Windows operating systems remain at risk. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques under T1068, which covers exploiting vulnerabilities in the operating system, and T1059, which involves executing commands through legitimate system utilities.
Mitigation strategies for CVE-2016-7259 focus on both immediate patching and operational security measures to reduce the attack surface. Microsoft released security updates in August 2016 that addressed this vulnerability through kernel-mode input validation improvements and memory management fixes within the graphics subsystem. Organizations should prioritize applying the relevant security patches as soon as possible, particularly for systems that cannot be immediately updated due to compatibility concerns. Additional protective measures include implementing application whitelisting policies that restrict execution of untrusted applications, disabling unnecessary graphics features and drivers, and monitoring for unusual graphics-related process activity that might indicate exploitation attempts. Security teams should also consider implementing behavioral monitoring solutions that can detect anomalous kernel-mode activities or privilege escalation events. The vulnerability's nature as a kernel-mode flaw means that traditional endpoint protection solutions may not be sufficient, requiring deeper system monitoring and integrity checking mechanisms. Organizations should also implement least privilege principles and regularly audit user account permissions to minimize the potential impact of successful exploitation, as the vulnerability can be leveraged to gain complete system control without requiring network-based attack vectors or complex multi-stage exploitation techniques.