CVE-2016-7905 in FFmpeg
Summary
by MITRE
The read_gab2_sub function in libavformat/avidec.c in FFmpeg before 3.1.4 allows remote attackers to cause a denial of service (NULL pointer used) via a crafted AVI file.
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Analysis
by VulDB Data Team • 10/12/2022
The vulnerability identified as CVE-2016-7905 represents a critical denial of service flaw within the FFmpeg multimedia framework, specifically affecting versions prior to 3.1.4. This issue resides in the read_gab2_sub function located within the libavformat/avidec.c file, which is responsible for decoding AVI (Audio Video Interleave) format files. The flaw manifests when processing maliciously crafted AVI files that contain malformed gab2 sub-chunk data, leading to a NULL pointer dereference condition that crashes the application.
The technical execution of this vulnerability involves the improper handling of AVI file structures during the decoding process. When FFmpeg encounters a specially crafted AVI file containing invalid gab2 sub-chunk information, the read_gab2_sub function attempts to access a NULL pointer reference, resulting in an application crash. This behavior constitutes a classic null pointer dereference vulnerability classified under CWE-476, which occurs when a program attempts to access a memory location through a pointer that has not been initialized to a valid address. The vulnerability is particularly concerning because it can be triggered remotely through the processing of untrusted AVI files, making it suitable for exploitation in various attack scenarios.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by remote attackers to perform denial of service attacks against systems processing multimedia content. Applications that utilize FFmpeg for video decoding, including media servers, content management systems, and multimedia processing platforms, become vulnerable to this attack vector. The vulnerability affects any system that processes AVI files without proper input validation, potentially leading to widespread service outages and system unavailability. The attack requires minimal privileges and can be executed through the simple act of opening or processing a malicious AVI file, making it particularly dangerous in environments where automated media processing occurs.
Mitigation strategies for CVE-2016-7905 primarily focus on upgrading to FFmpeg version 3.1.4 or later, which contains the necessary patches to address the NULL pointer dereference issue. System administrators should also implement input validation measures that sanitize AVI files before processing, particularly in environments where untrusted content is handled. Additionally, network-level filtering and sandboxing mechanisms can provide additional protection layers by preventing malicious files from reaching vulnerable applications. Organizations should conduct regular security assessments of their multimedia processing pipelines and ensure that all dependencies are kept up to date with the latest security patches. The vulnerability demonstrates the importance of proper input validation and error handling in multimedia processing libraries, as highlighted by ATT&CK technique T1203 which covers the exploitation of software vulnerabilities for denial of service attacks.