CVE-2016-3348 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, 1511, and 1607 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 • 09/16/2022
The Win32k Elevation of Privilege Vulnerability represents a critical flaw in Microsoft Windows kernel-mode drivers that affects multiple operating system versions including Vista SP2 through Windows 10 1607. This vulnerability resides within the win32k.sys driver which manages user-mode graphics components and handles kernel-mode operations for graphical user interface elements. The flaw stems from improper validation of user-supplied data within kernel memory, creating a path for local attackers to execute arbitrary code with elevated privileges. The vulnerability is classified as a privilege escalation issue that allows attackers with low-privilege user accounts to elevate their access level to system-level privileges, effectively compromising the entire operating system. This type of vulnerability is particularly dangerous because it operates at the kernel level where all system operations are processed with the highest privilege level, making it a prime target for exploitation in advanced persistent threat campaigns.
The technical implementation of this vulnerability involves a use-after-free condition within the win32k.sys driver when processing certain graphics-related objects. Attackers can craft malicious applications that trigger memory corruption in the kernel-mode driver, leading to arbitrary code execution with kernel-level privileges. The flaw specifically occurs during the handling of graphics objects in the Windows kernel, where insufficient input validation allows attackers to manipulate memory structures and potentially overwrite critical kernel data. This vulnerability aligns with CWE-476, which identifies "NULL Pointer Dereference" and related memory corruption issues in kernel-mode drivers. The exploitation requires local system access and typically involves crafting a malicious application that interacts with the graphics subsystem to trigger the vulnerable code path, making it particularly concerning for enterprise environments where user accounts may have elevated access rights.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete control over affected systems. Once successfully exploited, attackers can install malware, modify system files, access sensitive data, and establish persistent backdoors. The vulnerability affects a wide range of Windows operating systems, creating a broad attack surface that spans from legacy systems to newer releases, making it particularly attractive to threat actors seeking maximum impact. Organizations with systems running vulnerable versions of Windows face significant risk, as the vulnerability can be exploited through various attack vectors including social engineering, drive-by downloads, or by leveraging other initial access points. The vulnerability's presence in Windows Server 2008 and 2012 systems particularly impacts enterprise environments where these servers are commonly deployed for critical business operations, potentially leading to complete system compromise and data breaches.
Mitigation strategies for this vulnerability require immediate patch deployment through Microsoft's regular security updates, as the vendor released specific patches addressing the win32k.sys memory corruption issue. Organizations should prioritize updating all affected systems, particularly those running legacy versions of Windows that may not receive extended support. Additional defensive measures include implementing application whitelisting policies to prevent execution of unauthorized applications, disabling unnecessary graphics services, and monitoring for suspicious kernel-mode activity through endpoint detection and response solutions. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, while regular security assessments should verify that systems have been properly patched and configured. The vulnerability demonstrates the importance of maintaining up-to-date security patches and highlights the risks associated with running unsupported operating system versions. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be leveraged as part of broader attack chains, making it a critical focus area for security teams implementing comprehensive threat hunting and incident response procedures.