CVE-2016-3301 in Windows
Summary
by MITRE
The Windows font library 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; Windows 10 Gold, 1511, and 1607; Office 2007 SP3; Office 2010 SP2; Word Viewer; Skype for Business 2016; Lync 2013 SP1; Lync 2010; Lync 2010 Attendee; and Live Meeting 2007 Console allows remote attackers to execute arbitrary code via a crafted embedded font, aka "Windows Graphics Component RCE Vulnerability."
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Analysis
by VulDB Data Team • 03/13/2025
The vulnerability identified as CVE-2016-3301 represents a critical remote code execution flaw within the Windows font handling subsystem that affects multiple versions of Microsoft Windows operating systems and Office applications. This vulnerability resides in the Windows font library component responsible for processing embedded fonts in various document formats and graphics rendering contexts. The flaw specifically manifests when the system attempts to parse and render maliciously crafted font files, creating a pathway for remote attackers to execute arbitrary code with the privileges of the targeted user. The vulnerability impacts a wide range of Microsoft products including Windows Vista through Windows 10, various Office versions, and several communication applications, making it particularly dangerous due to its broad attack surface.
The technical nature of this vulnerability stems from improper input validation and memory handling within the Windows font processing engine. When a malicious font file is embedded in a document or delivered through network channels, the system's font library attempts to parse the font structure without adequate bounds checking or sanitization. This processing error creates memory corruption conditions that can be exploited by attackers to overwrite critical memory locations and inject malicious code. The vulnerability is classified under CWE-125 as an out-of-bounds read and CWE-787 as an out-of-bounds write, both of which are common attack vectors in memory corruption exploits. The flaw specifically affects the Windows Graphics Component, which is responsible for rendering vector graphics and font elements across the operating system.
The operational impact of CVE-2016-3301 extends far beyond simple remote code execution, as it provides attackers with complete system compromise capabilities. Successful exploitation allows attackers to execute malicious code with the same privileges as the targeted user, potentially leading to full system takeover, data exfiltration, and persistence mechanisms. The vulnerability can be triggered through multiple attack vectors including email attachments, web downloads, and network shares, making it highly suitable for automated exploitation campaigns. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter and T1068 for exploit for privilege escalation, as attackers can leverage the initial code execution to escalate privileges and maintain persistent access. The broad compatibility across multiple Microsoft products makes this vulnerability particularly attractive to threat actors seeking maximum impact with minimal effort.
Mitigation strategies for CVE-2016-3301 should focus on both immediate patching and operational security measures. Microsoft released security updates addressing this vulnerability through multiple monthly patches, with the primary fix being the implementation of proper input validation and memory bounds checking in the font processing components. Organizations should prioritize applying the relevant security updates from Microsoft, particularly the patches released in the July 2016 security bulletin. Additional protective measures include implementing strict email filtering policies to prevent malicious attachments, disabling automatic font rendering in web browsers and email clients, and deploying application whitelisting solutions to restrict execution of untrusted font files. Network segmentation and monitoring for unusual font processing activity can help detect potential exploitation attempts. The vulnerability's classification as a critical issue by Microsoft's security team underscores the importance of immediate remediation, as it was actively exploited in the wild prior to patch availability.