CVE-2014-9676 in FFmpeg
Summary
by MITRE
The seg_write_packet function in libavformat/segment.c in ffmpeg 2.1.4 and earlier does not free the correct memory location, which allows remote attackers to cause a denial of service ("invalid memory handler") and possibly execute arbitrary code via a crafted video that triggers a use after free.
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Analysis
by VulDB Data Team • 05/01/2022
The vulnerability identified as CVE-2014-9676 represents a critical memory management flaw within the ffmpeg multimedia framework, specifically affecting versions 2.1.4 and earlier. This issue resides in the seg_write_packet function located within the libavformat/segment.c file, which is part of the broader ffmpeg library used extensively for video processing and streaming. The flaw manifests as an improper memory handling mechanism that fails to correctly manage memory deallocation, creating a scenario where memory locations are not properly freed after use. This fundamental error in memory management creates a dangerous condition that can be exploited by remote attackers through carefully crafted video content.
The technical nature of this vulnerability stems from a use-after-free condition that occurs when the seg_write_packet function attempts to write packet data to segmented video files while simultaneously managing memory allocation and deallocation processes. When ffmpeg processes video segments, it allocates memory for packet data structures, processes the data, and then should properly free that memory. However, due to the flawed implementation in this function, the memory management logic fails to correctly identify and free the appropriate memory location. This mismanagement creates a situation where freed memory may still be referenced or accessed, leading to unpredictable behavior that manifests as invalid memory handler errors during processing operations.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution, making it particularly dangerous for systems that process untrusted video content. Attackers can craft malicious video files that, when processed by vulnerable ffmpeg versions, trigger the memory corruption condition. The use-after-free vulnerability creates opportunities for attackers to manipulate memory contents in ways that can be exploited to execute arbitrary code on the target system. This capability transforms what might initially appear as a denial of service condition into a full remote code execution vulnerability, potentially allowing attackers to gain unauthorized access to systems processing video content.
Systems utilizing ffmpeg for video processing, streaming, or transcoding operations are particularly at risk when running vulnerable versions of the software. This includes content delivery networks, video streaming platforms, media processing servers, and any application that relies on ffmpeg for video handling. The vulnerability is especially concerning in environments where users can upload or submit video content, as attackers can craft malicious files that will trigger the exploit during normal processing operations. The exploit requires no special privileges to execute, making it accessible to anyone capable of submitting crafted video files to a vulnerable system.
Mitigation strategies for CVE-2014-9676 focus primarily on immediate version updates to ffmpeg 2.2 or later, which contain the necessary patches to address the memory management flaw. Organizations should also implement proper input validation and sanitization for all video content processed through ffmpeg, including thorough file format validation and content inspection before processing. Network-level protections such as content filtering and sandboxing mechanisms can provide additional layers of defense. The vulnerability aligns with CWE-416, which describes use after free conditions, and represents a classic example of memory safety issues that can lead to remote code execution. From an ATT&CK perspective, this vulnerability maps to techniques involving remote code execution through software exploitation, specifically targeting the execution of malicious code via memory corruption vulnerabilities in multimedia processing libraries.