CVE-2018-12459 in FFmpeg
Summary
by MITRE
An inconsistent bits-per-sample value in the ff_mpeg4_decode_picture_header function in libavcodec/mpeg4videodec.c in FFmpeg 4.0 may trigger an assertion violation while converting a crafted AVI file to MPEG4, leading to a denial of service.
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Analysis
by VulDB Data Team • 03/27/2023
The vulnerability identified as CVE-2018-12459 represents a critical denial of service weakness within the FFmpeg multimedia framework that specifically affects the mpeg4videodec.c component. This flaw manifests when processing maliciously crafted AVI files that contain inconsistent bits-per-sample values during the MPEG4 video decoding process. The issue stems from insufficient input validation within the ff_mpeg4_decode_picture_header function where the system fails to properly handle malformed bitstream data, leading to assertion failures that terminate the decoding process.
The technical implementation of this vulnerability resides in the MPEG4 video decoder's handling of header information where the bits-per-sample parameter does not align with expected values during the picture header decoding phase. When FFmpeg encounters an AVI file containing crafted bitstream data with inconsistent sample bit depths, the decoding function triggers an assertion violation that causes the application to crash or become unresponsive. This behavior constitutes a classic denial of service condition where legitimate users cannot process valid video content due to the framework's inability to gracefully handle malformed input data.
From an operational perspective, this vulnerability presents significant risks in environments where FFmpeg is used for video processing, transcoding, or streaming applications. Attackers can exploit this weakness by preparing specially crafted AVI files that contain manipulated bits-per-sample values, causing any system running FFmpeg 4.0 to experience service disruption. The impact extends beyond simple application crashes as the vulnerability can be leveraged in automated processing systems where input validation is insufficient, potentially leading to widespread service degradation across multimedia processing pipelines.
The vulnerability aligns with CWE-691, which addresses insufficient input validation in multimedia processing systems, and demonstrates characteristics consistent with ATT&CK technique T1499.003 related to application or system exploitation for denial of service. Organizations utilizing FFmpeg for video processing must consider this vulnerability as part of their broader security posture, particularly in environments where user-uploaded content is processed without proper sanitization. The flaw underscores the importance of robust input validation and proper error handling in multimedia libraries that process untrusted data streams.
Mitigation strategies should focus on upgrading to FFmpeg versions that contain patches addressing this specific assertion violation, implementing comprehensive input validation for video file headers, and deploying sandboxed processing environments for untrusted content. Additionally, organizations should consider implementing automated scanning for malformed video files and establishing proper error handling procedures that prevent assertion failures from causing system-wide disruptions. Regular security audits of multimedia processing pipelines and adherence to secure coding practices in media libraries will help prevent similar vulnerabilities from emerging in future implementations.