CVE-2014-7937 in Chrome
Summary
by MITRE
Multiple off-by-one errors in libavcodec/vorbisdec.c in FFmpeg before 2.4.2, as used in Google Chrome before 40.0.2214.91, allow remote attackers to cause a denial of service (use-after-free) or possibly have unspecified other impact via crafted Vorbis I data.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/06/2022
The vulnerability identified as CVE-2014-7937 represents a critical security flaw within the FFmpeg multimedia processing library, specifically in the vorbisdec.c component responsible for decoding Vorbis I audio data. This issue affects versions prior to 2.4.2 and was notably present in Google Chrome versions before 40.0.2214.91, making it a widespread concern across multiple software platforms that rely on FFmpeg for audio processing capabilities. The vulnerability stems from multiple off-by-one errors that occur during the parsing and decoding of Vorbis I audio streams, creating a dangerous condition where memory management becomes compromised.
The technical implementation of this vulnerability involves buffer boundary violations that manifest as off-by-one errors within the Vorbis decoder logic. These errors occur when the decoder processes crafted Vorbis I data that contains malformed or maliciously constructed parameters that exceed expected buffer boundaries. The off-by-one conditions create scenarios where the decoder attempts to access memory locations beyond allocated buffers, leading to unpredictable behavior. When these errors are triggered during audio decoding operations, they can result in use-after-free conditions where previously freed memory blocks are accessed, potentially causing application crashes or more severe system instability.
The operational impact of CVE-2014-7937 extends beyond simple denial of service scenarios, as the vulnerability can potentially enable more sophisticated attacks depending on the execution environment. Remote attackers can exploit this weakness by crafting malicious Vorbis I audio files that, when processed by affected software, trigger the memory corruption conditions. The use-after-free vulnerability creates opportunities for memory corruption that could potentially be leveraged for arbitrary code execution, though the primary reported impact remains denial of service. This vulnerability particularly affects multimedia applications, web browsers, and media processing systems that utilize FFmpeg's Vorbis decoding capabilities, making it a significant concern for organizations relying on these technologies.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read errors, both of which are fundamental memory safety issues that affect the proper handling of audio data within multimedia libraries. From an ATT&CK framework perspective, this vulnerability maps to T1203, which involves legitimate programs that are used for exploitation, and T1059, which covers command and scripting interpreters, as attackers could potentially leverage the instability for further exploitation. The vulnerability's exploitation requires minimal privileges since it operates at the application level during media processing, making it particularly dangerous in web browsing environments where users encounter multimedia content automatically.
Mitigation strategies for CVE-2014-7937 primarily involve immediate patching of affected systems and software components, with the most effective solution being the upgrade to FFmpeg version 2.4.2 or later, which contains the necessary fixes for the off-by-one errors. Organizations should also implement network-level filtering to block potentially malicious Vorbis I audio content where possible, though this approach is not foolproof given the complexity of multimedia formats. Browser vendors and software distributors should ensure that their users are promptly updated to versions that include the patched FFmpeg libraries, particularly since the vulnerability affects widely used applications like Google Chrome. Additionally, implementing proper input validation and memory safety checks within applications that process multimedia content can provide additional defense-in-depth measures, though the primary remediation remains the application of the official patches provided by FFmpeg and affected software vendors.