CVE-2016-3304 in Windows
Summary
by MITRE
The Windows font library in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, 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," a different vulnerability than CVE-2016-3303.
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Analysis
by VulDB Data Team • 03/14/2025
The vulnerability identified as CVE-2016-3304 represents a critical remote code execution flaw within the Windows font handling subsystem that affects multiple Microsoft operating systems and applications. This vulnerability resides in the Windows Graphics Component, specifically within the font library that processes embedded fonts in various Microsoft products. The flaw manifests when the system attempts to parse maliciously crafted font files, particularly those containing embedded fonts that exploit memory corruption issues during the rendering process. The vulnerability is categorized under CWE-125 as an out-of-bounds read condition that can lead to arbitrary code execution, making it a prime target for exploitation in targeted attacks. Security researchers have classified this as a remote code execution vulnerability that leverages the inherent trust users place in font rendering capabilities, which are commonly encountered in documents, emails, and web content.
The technical exploitation of CVE-2016-3304 occurs when a user opens or previews a document containing a specially crafted embedded font that triggers a buffer overflow or memory corruption condition within the Windows font processing library. Attackers can leverage this vulnerability by embedding malicious font files within Office documents, PDFs, or other file formats that support embedded fonts, enabling remote code execution without requiring user interaction beyond opening the malicious file. The vulnerability specifically affects the Windows font rendering engine's handling of certain font attributes and metadata, particularly within the TrueType and OpenType font formats. When the system processes these malformed fonts, the memory corruption allows attackers to execute arbitrary code with the privileges of the current user, potentially leading to full system compromise. This vulnerability demonstrates the inherent risk in processing untrusted font data and highlights the attack surface exposed by rich text rendering components in Microsoft applications.
The operational impact of CVE-2016-3304 extends beyond simple remote code execution, as it represents a sophisticated attack vector that can be exploited across multiple Microsoft products and operating systems. Organizations running affected versions of Windows Vista, Windows Server 2008, Windows 7, and various Microsoft Office applications face significant risk, particularly in environments where users regularly open documents from untrusted sources. The vulnerability's exploitation can lead to complete system compromise, data exfiltration, and persistence mechanisms being established through the executed malicious code. Security professionals have noted that this vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter, as attackers can execute arbitrary commands through the compromised system. The attack surface is particularly broad due to the widespread use of font rendering in document processing and the fact that many users never consider font files as potential attack vectors. Organizations may experience significant disruption when attacks occur, as the vulnerability can be exploited through email attachments, web downloads, or network shares containing maliciously crafted documents.
Mitigation strategies for CVE-2016-3304 should focus on both immediate patching and operational security measures. Microsoft released security updates that address this vulnerability through the Windows Update mechanism, and organizations should prioritize deployment of these patches across all affected systems. Additionally, implementing application whitelisting policies can prevent execution of unauthorized font processing components, while disabling automatic font rendering in email clients and web browsers can reduce exposure. Network-based security controls such as firewalls and intrusion detection systems should be configured to monitor for suspicious font-related traffic patterns. Organizations should also consider implementing email filtering solutions that can detect and block documents containing potentially malicious embedded fonts. The vulnerability highlights the importance of maintaining current security patches and implementing defense-in-depth strategies that reduce the attack surface exposed by rich text rendering components. Security teams should conduct regular vulnerability assessments to identify systems running affected software versions and ensure comprehensive monitoring for exploitation attempts targeting this specific vulnerability.