CVE-2016-7214 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 bypass the ASLR protection mechanism via a crafted application, aka "Win32k Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 09/30/2022
The CVE-2016-7214 vulnerability represents a critical information disclosure flaw in Microsoft Windows kernel-mode drivers that specifically targets the Address Space Layout Randomization security mechanism. This vulnerability affects a broad range of Windows operating systems including Vista SP2 through Windows 10 version 1607, along with their respective server variants. The flaw exists within the win32k.sys driver component which manages user-mode graphics and windowing functions, making it a prime target for exploitation due to its privileged execution context and extensive system integration.
The technical implementation of this vulnerability stems from improper handling of memory layout information within the kernel-mode driver components. When a crafted application executes with elevated privileges, it can manipulate the driver to leak memory addresses that would normally be randomized by ASLR protection. This information disclosure allows attackers to bypass the memory protection mechanisms that randomize the locations of system components, effectively reducing the security benefits of ASLR. The vulnerability specifically exploits the way the win32k.sys driver processes certain graphics-related API calls, creating a pathway for information disclosure that can be leveraged to determine the base addresses of critical system modules.
The operational impact of this vulnerability is significant as it fundamentally undermines one of the core memory protection mechanisms in modern operating systems. Attackers who successfully exploit this vulnerability can gain crucial information about the memory layout of the target system, which enables them to perform more sophisticated attacks such as return-oriented programming exploits or other advanced techniques that require knowledge of memory addresses. The vulnerability operates at the kernel level, meaning that successful exploitation can lead to complete system compromise, allowing attackers to execute arbitrary code with the highest privilege level. This makes it particularly dangerous in enterprise environments where a single compromised endpoint could potentially lead to widespread system infiltration.
Organizations should implement immediate mitigations including applying the relevant Microsoft security updates that address this vulnerability, disabling unnecessary graphics functionality where possible, and implementing additional security controls such as kernel-mode exploit protection. The vulnerability aligns with CWE-200, which addresses "Information Exposure," and maps to ATT&CK technique T1068, "Exploitation for Privilege Escalation," and T1059, "Command and Scripting Interpreter," as attackers can leverage the leaked information to craft more effective exploitation payloads. Network segmentation and monitoring for unusual graphics API calls can help detect potential exploitation attempts, while regular security assessments should focus on identifying systems running vulnerable versions of Windows and ensuring timely patch deployment to maintain the integrity of ASLR protections.