CVE-2015-2455 in Windows
Summary
by MITRE
Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT Gold and 8.1, Windows 10, Office 2007 SP3 and 2010 SP2, Live Meeting 2007 Console, Lync 2010, Lync 2010 Attendee, Lync 2013 SP1, Lync Basic 2013 SP1, Silverlight before 5.1.40728, and .NET Framework 3.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, 4.5.2, and 4.6 allow remote attackers to execute arbitrary code via a crafted TrueType font, aka "TrueType Font Parsing Vulnerability," a different vulnerability than CVE-2015-2456.
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Analysis
by VulDB Data Team • 05/23/2025
The vulnerability identified as CVE-2015-2455 represents a critical TrueType font parsing flaw that affects multiple Microsoft operating systems and software frameworks. This vulnerability resides in the Windows font handling subsystem and specifically targets the processing of TrueType font files through the Windows Graphics Device Interface. The flaw enables remote attackers to execute arbitrary code when a victim's system processes a maliciously crafted TrueType font file, making it a significant vector for code execution attacks. The vulnerability impacts a broad range of Microsoft products including Windows Vista through Windows 10, various Office suites, Lync and Skype for Business applications, Silverlight runtime environments, and multiple .NET Framework versions. The attack surface is extensive given that TrueType fonts are commonly embedded in documents, web pages, and email attachments, providing attackers with numerous potential entry points. This vulnerability is particularly concerning because it operates at the graphics rendering level where many applications process font files without proper input validation, creating a fundamental security gap in the Windows ecosystem.
The technical exploitation of this vulnerability occurs through a buffer overflow condition within the font parsing code that handles TrueType font structures. When the Windows Graphics Device Interface encounters a malformed TrueType font file, the parsing routine fails to properly validate the font data structure, leading to memory corruption. This memory corruption allows attackers to overwrite critical memory locations and execute malicious code with the privileges of the compromised application. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, where the font parsing code allocates insufficient memory for font data structures, causing a buffer overrun that can be leveraged for code execution. The attack typically requires the user to open or preview a document containing the malicious font, or to visit a web page that automatically renders the font. The exploitation mechanism is consistent across all affected platforms since they all utilize the same underlying Windows font processing libraries, making this vulnerability particularly dangerous for enterprise environments where users may encounter malicious content from various sources.
The operational impact of CVE-2015-2455 extends beyond simple code execution to encompass significant security risks for organizations relying on affected Microsoft products. The vulnerability's prevalence across multiple Windows versions and applications creates a substantial attack surface that security teams must address comprehensively. Organizations face potential data breaches, system compromise, and lateral movement opportunities for attackers who successfully exploit this vulnerability. The impact is amplified by the fact that the vulnerability can be triggered through email attachments, web downloads, or document previews, making it difficult to prevent through traditional security measures. The vulnerability's classification under the ATT&CK framework as a technique for code execution through application input validation (T1059.007) indicates that it aligns with common attack patterns used in enterprise security breaches. Additionally, the vulnerability's presence in both client and server operating systems means that attackers could potentially compromise entire network infrastructures through targeted attacks against specific users or systems. The complexity of the attack vector and the wide range of affected software components make this vulnerability particularly challenging to defend against.
Mitigation strategies for CVE-2015-2455 require a multi-layered approach that addresses both immediate remediation and long-term security posture improvements. The primary defense mechanism involves installing the relevant Microsoft security patches that address the font parsing vulnerability in the Windows Graphics Device Interface. Organizations should prioritize patch deployment across all affected systems, particularly those with high-value assets or limited network segmentation. Network-based mitigations include implementing web content filtering solutions that can detect and block malicious font files, as well as configuring email security appliances to scan for suspicious font attachments. The implementation of application whitelisting policies can prevent execution of unauthorized font processing applications, while disabling automatic font rendering in web browsers and email clients can reduce attack surface. Security teams should also consider implementing monitoring solutions that can detect unusual font processing activities or memory corruption patterns that might indicate exploitation attempts. The vulnerability's nature as a rendering engine issue makes it particularly challenging to defend against through traditional network security controls, necessitating endpoint protection measures and user education about risky file attachments. Regular vulnerability assessments and penetration testing should be conducted to verify that patches have been properly deployed and that no residual vulnerabilities exist within the affected systems.