CVE-2009-0946 in FreeType
Summary
by MITRE
Multiple integer overflows in FreeType 2.3.9 and earlier allow remote attackers to execute arbitrary code via vectors related to large values in certain inputs in (1) smooth/ftsmooth.c, (2) sfnt/ttcmap.c, and (3) cff/cffload.c.
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Analysis
by VulDB Data Team • 09/02/2019
The vulnerability identified as CVE-2009-0946 represents a critical security flaw within the FreeType font rendering library version 2.3.9 and earlier. This library serves as a fundamental component in numerous operating systems and applications for handling font rendering, making it a prime target for attackers seeking to exploit system vulnerabilities. The flaw manifests as multiple integer overflows that can be triggered through carefully crafted font files, potentially allowing remote attackers to execute arbitrary code on affected systems. The vulnerability affects three distinct modules within the FreeType codebase, specifically smooth/ftsmooth.c, sfnt/ttcmap.c, and cff/cffload.c, each representing different aspects of font processing and rendering.
The technical implementation of this vulnerability stems from inadequate input validation within the font parsing routines. When processing font files containing maliciously crafted data, the FreeType library fails to properly validate integer values, leading to integer overflows that can corrupt memory structures. These overflows occur during the parsing of font tables and glyph data, particularly in scenarios involving large or malformed values in font metadata. The overflow conditions create situations where buffer boundaries are exceeded, potentially allowing attackers to overwrite adjacent memory locations with malicious code or manipulate program execution flow. The vulnerability is particularly dangerous because it can be triggered through legitimate font rendering operations, making it difficult to detect and prevent through traditional network-based security measures.
The operational impact of CVE-2009-0946 extends across multiple system environments where FreeType is utilized, including web browsers, operating systems, desktop applications, and server software. Attackers can exploit this vulnerability by delivering malicious font files through various attack vectors such as email attachments, compromised websites, or malicious downloads. The remote execution capability means that a single compromised font file can potentially affect numerous systems without user interaction, making it particularly dangerous in enterprise environments. Successful exploitation could result in complete system compromise, allowing attackers to execute arbitrary commands, escalate privileges, or establish persistent backdoors. The vulnerability's presence in core font rendering components means that even benign-looking documents or web pages could serve as attack vectors, significantly expanding the potential attack surface.
Security professionals should prioritize immediate remediation of this vulnerability by upgrading to FreeType version 2.4.0 or later, which contains patches addressing the integer overflow conditions. Organizations should implement comprehensive vulnerability management processes that include regular security assessments of font processing components and monitoring for unusual font-related activities. Network segmentation and application whitelisting can provide additional defense-in-depth measures, while regular security updates and patch management procedures should be enforced across all systems utilizing FreeType. The vulnerability aligns with CWE-190, which describes integer overflow conditions, and represents a common pattern in software security vulnerabilities related to improper input validation and memory handling. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and remote code execution, potentially enabling adversaries to establish persistent access to target systems through font-based attack vectors that leverage the widespread use of font rendering libraries in modern computing environments.