CVE-2017-0246 in Windows
Summary
by MITRE
The Graphics Component in the kernel-mode drivers in 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 or in Windows 7 for x64-based Systems and later, cause denial of service, aka "Win32k Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 12/22/2020
The vulnerability identified as CVE-2017-0246 represents a critical privilege escalation flaw within the Windows kernel-mode graphics component known as win32k.sys. This vulnerability affects multiple Windows operating systems including server and client versions, creating a significant attack surface that adversaries can exploit to elevate their privileges from standard user to system level access. The flaw resides in the graphics subsystem's handling of user-mode to kernel-mode transitions, specifically within the Windows Graphics Component that manages graphics rendering operations. The vulnerability is classified under CWE-119 as a buffer overflow or memory corruption issue that occurs during kernel-mode operations, making it particularly dangerous as it operates at the highest privilege level of the operating system.
The technical execution of this vulnerability involves a crafted application that leverages improper input validation within the win32k.sys driver. When a malicious application interacts with the graphics subsystem, it can trigger a memory corruption condition that allows arbitrary code execution in kernel space. The flaw specifically manifests when the graphics component processes certain graphical operations, particularly those involving user-mode applications that attempt to manipulate kernel-mode data structures. Attackers can exploit this by creating specially crafted graphical content or by manipulating existing graphics APIs to force the kernel driver into an exploitable state. The vulnerability's impact extends to x64-based systems running Windows 7 and later versions, with the attack vector requiring local system access and execution privileges, though the ultimate goal is to achieve system-level privileges through kernel-mode code execution.
The operational impact of CVE-2017-0246 is severe and multifaceted, as it provides attackers with a direct path to system compromise through local privilege escalation. Once successfully exploited, the vulnerability allows attackers to execute arbitrary code with kernel-level privileges, enabling them to bypass standard security controls, install persistent backdoors, modify system files, and potentially access sensitive data. The vulnerability's classification aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and T1059 which covers "Command and Scripting Interpreter" as attackers can leverage this vulnerability to gain full system control. Organizations affected by this vulnerability face potential data breaches, system compromise, and complete loss of operational integrity, particularly in environments where users have the ability to execute applications or where default user privileges are not properly restricted.
Mitigation strategies for CVE-2017-0246 should focus on immediate patch deployment and system hardening measures. Microsoft released security updates that address this vulnerability through the standard Windows Update process, and organizations should prioritize immediate deployment of the relevant patches. Additionally, implementing application whitelisting policies, disabling unnecessary graphics services, and restricting user privileges can significantly reduce the attack surface. Security professionals should also consider monitoring for suspicious graphics-related processes and kernel-mode activities that might indicate exploitation attempts. The vulnerability's nature makes it particularly susceptible to exploit mitigation through exploit protection features, and organizations should enable features such as Data Execution Prevention and Address Space Layout Randomization to make exploitation more difficult. Regular security assessments and vulnerability scanning should include checks for unpatched systems running affected Windows versions to prevent potential compromise through this and similar kernel-mode vulnerabilities.