CVE-2017-8683 in Windows
Summary
by MITRE
Windows graphics on Microsoft 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, 1607, and 1703, and Windows Server 2016, allows an attacker to execute remote code by the way it handles embedded fonts, aka "Win32k Graphics Remote Code Execution Vulnerability". This CVE ID is unique from CVE-2017-8682.
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Analysis
by VulDB Data Team • 01/12/2021
The vulnerability identified as CVE-2017-8683 represents a critical security flaw in Microsoft Windows operating systems that affects graphics rendering functionality through the Win32k subsystem. This vulnerability specifically targets how Windows handles embedded fonts within graphics contexts, creating a remote code execution vector that could be exploited by malicious actors. The affected platforms span multiple Windows versions including server and client operating systems, making this vulnerability particularly widespread and concerning for enterprise environments. The issue resides in the Windows graphics subsystem's processing of font data, which can be manipulated to trigger arbitrary code execution when legitimate font rendering operations occur.
The technical exploitation of this vulnerability occurs through the manipulation of embedded font data within graphics objects, particularly when Windows processes these fonts through the Win32k graphics driver. When a maliciously crafted font is embedded in a graphics context, the vulnerable code path in the graphics subsystem fails to properly validate font data before processing, allowing attackers to execute arbitrary code with the privileges of the targeted user. This flaw operates at the kernel level within the Win32k.sys driver, which handles graphics operations and user interface components, making it particularly dangerous as it can potentially bypass user-mode protections. The vulnerability is classified under CWE-121, which addresses stack-based buffer overflow conditions, though the actual exploitation mechanism involves heap-based memory corruption through improper font data handling.
The operational impact of CVE-2017-8683 extends significantly across enterprise networks due to the widespread deployment of affected Windows versions and the potential for remote exploitation without user interaction. Attackers can leverage this vulnerability through various attack vectors including malicious websites, email attachments, or compromised applications that render graphics with embedded fonts. The vulnerability's classification under the ATT&CK framework places it within the initial access and execution phases, specifically targeting the 'Exploit Public-Facing Application' and 'Command and Scripting Interpreter' techniques. Organizations running affected systems face substantial risk of unauthorized access, data exfiltration, and potential lateral movement within their networks, as successful exploitation could provide attackers with system-level privileges.
Mitigation strategies for CVE-2017-8683 should prioritize immediate patch deployment through Microsoft's security updates, as the vulnerability has been addressed through official Windows updates. Organizations should implement network segmentation and monitoring to detect potential exploitation attempts, particularly focusing on unusual graphics rendering activities or font-related data processing. Additional defensive measures include disabling unnecessary font rendering capabilities, implementing application whitelisting policies, and conducting regular vulnerability assessments to identify systems that may not have received the required patches. The vulnerability's remediation aligns with Microsoft's recommended security practices for Windows systems, emphasizing the importance of maintaining up-to-date security patches and implementing comprehensive endpoint protection solutions to prevent exploitation attempts.