CVE-2014-6317 in Windows
Summary
by MITRE
Array index error in win32k.sys in the kernel-mode drivers in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows remote attackers to cause a denial of service (reboot) via a crafted TrueType font, aka "Denial of Service in Windows Kernel Mode Driver Vulnerability."
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/14/2024
The vulnerability identified as CVE-2014-6317 represents a critical array index error within the win32k.sys kernel-mode driver component of Microsoft Windows operating systems. This flaw exists in multiple versions spanning Windows Server 2003 through Windows 8.1, affecting both desktop and server variants, and demonstrates the persistent nature of kernel-level vulnerabilities that can compromise system stability and availability. The vulnerability specifically manifests when processing TrueType font files, making it particularly dangerous as font rendering is a fundamental system function that occurs frequently during normal operations.
The technical flaw stems from improper bounds checking within the win32k.sys driver responsible for handling graphical user interface components and window management functions. When a maliciously crafted TrueType font file is processed by the system, the driver fails to properly validate array indices, leading to potential memory corruption that can trigger system instability. This vulnerability operates at the kernel level, meaning that exploitation can result in complete system compromise, though in this specific case the primary impact is a denial of service condition that forces system reboot. The flaw aligns with CWE-129, which describes improper validation of array indices, and represents a classic buffer overflow vulnerability that has been a persistent threat in operating system kernel code.
The operational impact of CVE-2014-6317 extends beyond simple denial of service, as it can be leveraged by remote attackers to disrupt critical services and potentially create opportunities for further exploitation. The vulnerability's ability to cause system reboots makes it particularly concerning in enterprise environments where availability is paramount, as it can be used to create persistent disruption or as part of larger attack campaigns. Attackers can craft malicious font files that, when processed by vulnerable systems, trigger the array index error and force system restarts, effectively creating a denial of service attack that can be executed remotely without requiring authentication. This characteristic places the vulnerability in the ATT&CK framework under the T1499 category for network denial of service, specifically targeting system exploitation and availability compromise.
Mitigation strategies for CVE-2014-6317 primarily involve applying Microsoft security patches and updates as soon as they become available, since this vulnerability was addressed through the Windows Update mechanism. System administrators should prioritize patch management for all affected Windows versions and implement network segmentation to limit potential attack vectors. Additional defensive measures include disabling unnecessary font processing capabilities, implementing application whitelisting to prevent execution of untrusted font files, and monitoring for suspicious font-related activities in system logs. The vulnerability demonstrates the importance of kernel-mode security and highlights the need for rigorous code review processes, particularly for components that handle untrusted input from external sources. Organizations should also consider implementing intrusion detection systems that can identify potential exploitation attempts targeting similar kernel-level vulnerabilities, as these attacks often follow predictable patterns and can be detected through behavioral analysis.