CVE-2017-11763 in Windows
Summary
by MITRE
The Microsoft Graphics Component 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 a remote code execution vulnerability in the way it handles specially crafted embedded fonts, aka "Microsoft Graphics Remote Code Execution Vulnerability". This CVE ID is unique from CVE-2017-11763.
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Analysis
by VulDB Data Team • 01/16/2021
The Microsoft Graphics Component vulnerability identified as CVE-2017-11763 represents a critical remote code execution flaw that affects multiple versions of the windows operating system family. This vulnerability specifically targets the graphics rendering subsystem's handling of embedded fonts, creating a pathway for malicious actors to execute arbitrary code on affected systems. The flaw exists within the core graphics processing functionality that interprets and renders font files, making it particularly dangerous as font rendering occurs frequently during normal system operations. The vulnerability impacts a wide range of microsoft products including server and client operating systems, demonstrating the widespread nature of the flaw across the windows ecosystem.
The technical exploitation mechanism involves crafting specially designed embedded font files that trigger buffer overflow conditions or memory corruption within the graphics component's font parsing routines. When a user opens a malicious document containing such fonts or when the system renders fonts from untrusted sources, the vulnerable code path is executed. This vulnerability falls under the CWE-121 stack-based buffer overflow category, where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw specifically affects the way the graphics component processes font data structures, particularly when handling embedded font tables and metadata within font files. Attackers can leverage this vulnerability to gain complete control over affected systems, potentially leading to full system compromise.
The operational impact of CVE-2017-11763 is severe and far-reaching, as it enables remote code execution without requiring user interaction in many scenarios. The vulnerability can be exploited through various attack vectors including email attachments, web downloads, or document files containing malicious fonts. Once successfully exploited, the vulnerability allows attackers to execute code with the privileges of the current user, potentially leading to privilege escalation and complete system compromise. The attack surface is extensive given that font rendering occurs in numerous applications and contexts, making this vulnerability particularly dangerous in enterprise environments where users frequently open documents from external sources. The vulnerability also aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation.
Mitigation strategies for CVE-2017-11763 should include immediate deployment of microsoft security patches and updates, which address the underlying buffer overflow conditions in the graphics component. Organizations should implement network segmentation and access controls to limit exposure, particularly in environments where users may encounter untrusted documents. Browser security configurations should be hardened to prevent automatic font rendering from untrusted sources, and email filtering systems should be enhanced to detect and block documents containing suspicious font content. Security monitoring should focus on unusual font processing activities and memory access patterns that might indicate exploitation attempts. Additionally, system administrators should consider implementing application whitelisting policies to restrict font processing to trusted applications and ensure that automatic font embedding features are disabled in untrusted environments. The vulnerability demonstrates the importance of keeping graphics and font processing components updated, as these subsystems often receive less scrutiny than core operating system components.