CVE-2014-8541 in FFmpeg
Summary
by MITRE
libavcodec/mjpegdec.c in FFmpeg before 2.4.2 considers only dimension differences, and not bits-per-pixel differences, when determining whether an image size has changed, which allows remote attackers to cause a denial of service (out-of-bounds access) or possibly have unspecified other impact via crafted MJPEG data.
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Analysis
by VulDB Data Team • 02/27/2022
The vulnerability identified as CVE-2014-8541 represents a critical flaw in the FFmpeg multimedia framework's handling of MJPEG (Motion JPEG) video decoding. This issue resides within the libavcodec/mjpegdec.c component and affects FFmpeg versions prior to 2.4.2, making it a persistent threat across multiple release cycles. The vulnerability stems from an incomplete implementation of image size validation logic that fails to account for crucial dimensional parameters beyond simple width and height measurements.
The technical flaw manifests when the MJPEG decoder processes malformed video data that contains inconsistent bits-per-pixel values while maintaining seemingly valid dimension parameters. The decoder's logic only examines whether the image dimensions have changed between frames, neglecting to verify that the bits-per-pixel values remain consistent with the established frame parameters. This oversight creates a scenario where an attacker can craft malicious MJPEG data that appears to maintain valid dimensions but introduces unexpected bit depth variations, leading to memory access violations.
This vulnerability operates under the principle of insufficient validation and can be classified under CWE-129, which addresses insufficient validation of length of buffers. The operational impact of CVE-2014-8541 extends beyond simple denial of service to potentially enable more sophisticated attacks. Remote attackers can exploit this weakness to trigger out-of-bounds memory access patterns that may result in application crashes, system instability, or in some cases, arbitrary code execution depending on the specific memory corruption patterns. The vulnerability affects any system that processes MJPEG video streams through FFmpeg, including media servers, content delivery networks, and multimedia applications.
The attack surface for this vulnerability is extensive given FFmpeg's widespread adoption across various operating systems, media players, and server applications. Systems that decode MJPEG streams from untrusted sources, such as web browsers processing embedded video content or media servers handling user-uploaded videos, become particularly vulnerable. The exploitability of this vulnerability aligns with ATT&CK technique T1203, which involves the use of malicious files to gain access to systems, and T1059, which covers the execution of malicious code through various attack vectors. Organizations utilizing FFmpeg in their multimedia processing pipelines should prioritize immediate patching to address this vulnerability, as the potential for remote code execution cannot be ruled out in certain configurations.
Mitigation strategies should include immediate deployment of FFmpeg version 2.4.2 or later, which contains the necessary patches to properly validate bits-per-pixel values during MJPEG decoding. Additionally, implementing input validation measures such as restricting the types of MJPEG streams processed and establishing proper bounds checking for all decoded video parameters can provide defense-in-depth protection. Network segmentation and access controls should be implemented to limit exposure of systems processing untrusted video content. Regular security assessments of multimedia processing components and monitoring for unusual system behavior can help detect potential exploitation attempts. The vulnerability serves as a reminder of the importance of comprehensive input validation in multimedia processing libraries and the critical need for thorough testing of edge cases in image and video decoding implementations.