CVE-2016-1709 in Chrome
Summary
by MITRE
Heap-based buffer overflow in the ByteArray::Get method in data/byte_array.cc in Google sfntly before 2016-06-10, as used in Google Chrome before 52.0.2743.82, allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted SFNT font.
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Analysis
by VulDB Data Team • 09/09/2022
The vulnerability identified as CVE-2016-1709 represents a critical heap-based buffer overflow affecting the sfntly library component within Google Chrome browser. This flaw exists in the ByteArray::Get method implementation within the data/byte_array.cc file, specifically impacting versions of sfntly released prior to June 10, 2016. The vulnerability manifests when processing SFNT (Scalable Font Transport) font files, which are fundamental to font rendering across various operating systems and applications. SFNT fonts serve as the foundation for modern typography systems, encompassing formats such as TrueType, OpenType, and others that define character shapes and spacing information.
The technical exploitation of this buffer overflow occurs through improper bounds checking within the ByteArray::Get method when handling crafted SFNT font data. Attackers can construct malicious font files that trigger memory corruption during the parsing process, leading to memory layout manipulation and potential arbitrary code execution. The heap-based nature of the vulnerability indicates that the overflow occurs within dynamically allocated memory regions, making exploitation more complex but potentially more dangerous than stack-based alternatives. This particular implementation flaw demonstrates inadequate input validation and memory management practices, where the system fails to properly verify array bounds before performing memory access operations. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the heap-based nature suggests additional complexity in exploitation vectors.
The operational impact of CVE-2016-1709 extends beyond simple denial of service scenarios, as it potentially enables remote code execution capabilities that could allow attackers to compromise affected systems. When a user opens a webpage containing a maliciously crafted font file, the browser's rendering engine processes the font data through the vulnerable sfntly library, triggering the buffer overflow condition. This vulnerability affects not only Google Chrome but also any application utilizing the affected sfntly library version, creating a widespread attack surface across multiple software platforms. The potential for unspecified other impacts suggests that exploitation could lead to privilege escalation, information disclosure, or complete system compromise depending on the execution environment and attack vector employed. According to ATT&CK framework, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: PowerShell) and T1203 (Exploitation for Client Execution) as attackers could leverage the font processing functionality to execute malicious payloads.
Mitigation strategies for CVE-2016-1709 primarily involve immediate patching of affected software components, with Google releasing Chrome version 52.0.2743.82 to address the vulnerability. System administrators should implement comprehensive patch management protocols to ensure all affected applications and browsers are updated promptly. Additional defensive measures include implementing strict font validation policies, disabling automatic font loading from untrusted sources, and deploying network-based intrusion detection systems to monitor for suspicious font-related traffic patterns. Organizations should also consider implementing sandboxing mechanisms that isolate font processing operations to limit potential damage from successful exploitation attempts. The vulnerability highlights the importance of secure coding practices in font processing libraries and demonstrates the critical need for regular security assessments of core system components that handle external data input. Proper input sanitization, memory boundary checks, and robust error handling should be implemented across all font parsing functionality to prevent similar vulnerabilities from emerging in future implementations.