CVE-2016-10328 in Outside In Technology
Summary
by MITRE
FreeType 2 before 2016-12-16 has an out-of-bounds write caused by a heap-based buffer overflow related to the cff_parser_run function in cff/cffparse.c.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/24/2024
The vulnerability identified as CVE-2016-10328 represents a critical heap-based buffer overflow in the FreeType 2 font rendering library, specifically affecting versions prior to the December 16, 2016 release. This flaw resides within the cff_parser_run function located in the cff/cffparse.c source file, which processes Compact Font Format (CFF) font data. The out-of-bounds write condition occurs when the library attempts to parse malformed CFF font files, creating a potential pathway for arbitrary code execution. FreeType is widely deployed across operating systems and applications as a core font rendering component, making this vulnerability particularly dangerous as it could be exploited through various attack vectors including email attachments, web content, or document files containing malicious fonts.
The technical implementation of this vulnerability stems from inadequate input validation within the CFF parser's handling of font data structures. When processing Compact Font Format data, the cff_parser_run function fails to properly bounds-check array accesses during the parsing of font dictionaries and character glyph data. This deficiency allows an attacker to craft specially malformed CFF font files that trigger memory corruption when the parser attempts to write beyond allocated buffer boundaries. The heap-based nature of the overflow means that the vulnerability can be exploited to overwrite adjacent memory regions, potentially leading to stack corruption, heap corruption, or arbitrary code execution. The flaw aligns with CWE-121, which categorizes heap-based buffer overflow conditions, and represents a classic example of improper input validation in parsing functions.
The operational impact of CVE-2016-10328 extends across numerous computing environments where FreeType is utilized as a font rendering engine. This includes desktop operating systems such as Windows, macOS, and various Linux distributions, as well as mobile platforms and embedded systems. Applications that rely on FreeType for font rendering, including web browsers, office suites, graphic design tools, and PDF viewers, become vulnerable to exploitation. Attackers could leverage this vulnerability through supply chain attacks, malicious email attachments, compromised websites, or infected documents, potentially gaining unauthorized code execution privileges on affected systems. The vulnerability's exploitation potential is particularly concerning given FreeType's widespread adoption, as a successful attack could lead to complete system compromise, data exfiltration, or persistent backdoor installation.
Mitigation strategies for CVE-2016-10328 require immediate deployment of the patched FreeType 2 version released on December 16, 2016, which addresses the buffer overflow through proper bounds checking and input validation. System administrators should prioritize updating all affected applications that utilize FreeType, particularly those handling untrusted font data. Additional protective measures include implementing strict input validation for font files in web applications, deploying sandboxing mechanisms for font processing, and enabling operating system security features such as address space layout randomization and data execution prevention. Organizations should also consider network-based intrusion detection systems to monitor for exploitation attempts and maintain comprehensive incident response procedures. The vulnerability demonstrates the importance of regular security updates and proper input validation practices, aligning with ATT&CK technique T1059 for execution through legitimate system processes and T1203 for exploitation of software vulnerabilities.