CVE-2016-3221 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 and 1511 allow local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability," a different vulnerability than CVE-2016-3218.
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Analysis
by VulDB Data Team • 08/23/2022
The vulnerability identified as CVE-2016-3221 represents a critical privilege escalation flaw within the Windows kernel-mode drivers, specifically affecting multiple versions of the microsoft windows operating system. This vulnerability operates through the win32k.sys driver which manages user interface components and system calls, making it a prime target for attackers seeking to elevate their privileges from standard user level to system level access. The flaw allows local attackers to execute malicious code that can manipulate kernel memory structures and bypass security mechanisms that normally prevent unauthorized privilege escalation. This vulnerability is classified under the common weakness enumeration CWE-264 as it involves improper privileges management within the kernel mode components of the operating system.
The technical implementation of this vulnerability exploits weaknesses in how the win32k.sys driver handles certain user-mode input validation processes. Attackers can craft malicious applications that trigger specific code paths within the kernel driver, causing memory corruption that allows arbitrary code execution with kernel-level privileges. The vulnerability stems from insufficient validation of input parameters passed to kernel-mode functions, particularly those related to graphics and user interface operations. When the system processes these malformed inputs, it can lead to memory overwrite conditions that attackers can leverage to execute malicious payloads with elevated privileges. This type of vulnerability falls under the attack pattern category of privilege escalation as defined by the mitre attack framework, specifically targeting the execution of malicious code with system-level privileges.
The operational impact of CVE-2016-3221 is severe as it provides attackers with a direct path to system compromise from a local user position. Once exploited, successful exploitation results in complete system control, allowing attackers to install malware, modify system files, access sensitive data, and potentially establish persistence mechanisms. The vulnerability affects a broad range of windows operating systems including vista, server 2008, windows 7, 8.1, and windows 10, making it particularly dangerous as it impacts both desktop and server environments. Security researchers have noted that this vulnerability is particularly concerning because it requires minimal user interaction beyond running a malicious application, and the exploitation can occur without requiring network connectivity or specific external attack vectors.
Organizations should implement immediate mitigations including applying microsoft security patches as soon as they become available, implementing application whitelisting policies to prevent execution of unauthorized applications, and monitoring for suspicious kernel-mode activities. System administrators should also consider implementing additional security controls such as disabling unnecessary user interface components, restricting local user privileges, and maintaining comprehensive system monitoring to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of keeping operating systems updated and maintaining robust security hygiene practices. Security professionals should also consider implementing behavioral monitoring solutions that can detect anomalous kernel-mode activities that may indicate exploitation attempts, as the vulnerability operates at a low-level kernel position that traditional endpoint protection may not easily detect.