CVE-2015-2506 in Windows
Summary
by MITRE
atmfd.dll in the Adobe Type Manager Library in 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, and Windows 10 allows remote attackers to cause a denial of service (system crash) via a crafted OpenType font, aka "OpenType Font Parsing Vulnerability."
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/14/2022
The vulnerability identified as CVE-2015-2506 represents a critical flaw in the Adobe Type Manager Library component of Microsoft Windows operating systems. This vulnerability specifically affects the atmfd.dll module which handles OpenType font processing within the Windows graphics subsystem. The flaw exists in multiple Windows versions including Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012, Windows RT, and Windows 10, making it one of the most widespread font-related vulnerabilities in the Windows ecosystem. The vulnerability falls under CWE-125, which describes out-of-bounds read conditions that can lead to system instability and potential exploitation.
The technical nature of this vulnerability stems from improper input validation within the OpenType font parsing routines of the Adobe Type Manager Library. When a maliciously crafted OpenType font file is processed by the system, the parsing logic fails to properly validate array bounds and memory access patterns, leading to a buffer overflow condition. This occurs during the rendering process when the system attempts to parse font metrics and glyph data from the malicious font file. The flaw allows attackers to manipulate memory structures through carefully constructed font files, causing the Windows graphics subsystem to crash and potentially leading to a complete system hang or reboot.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a significant security risk that could be exploited in various attack scenarios. Remote attackers can leverage this vulnerability through web browsing, email attachments, or file sharing mechanisms where OpenType fonts are automatically processed and rendered. The vulnerability's reach is particularly concerning given that Windows systems automatically process font files during normal operation, making exploitation relatively easy. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1203, which involves the use of malicious files to gain system access, and T1059, which covers the execution of malicious code through system processes.
Mitigation strategies for CVE-2015-2506 should focus on both immediate patching and operational security measures. Microsoft released security updates that addressed this vulnerability through the Windows Update mechanism, requiring administrators to apply the relevant patches promptly. Organizations should implement network segmentation to limit exposure and disable automatic font rendering in untrusted environments. Additional protective measures include implementing application whitelisting policies to prevent execution of unsigned font files, monitoring for suspicious font file downloads, and maintaining updated antivirus signatures that can detect malicious font files. The vulnerability also underscores the importance of regular security assessments and vulnerability management programs to identify and remediate similar issues in other system components. Security teams should consider implementing the principle of least privilege for font processing operations and ensure that font rendering is isolated from core system processes to limit potential impact.