CVE-2013-2277 in FFmpeg
Summary
by MITRE
The ff_h264_decode_seq_parameter_set function in h264_ps.c in libavcodec in FFmpeg before 1.1.3 does not validate the relationship between luma depth and chroma depth, which allows remote attackers to cause a denial of service (out-of-bounds array access and application crash) or possibly have unspecified other impact via crafted H.264 data.
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Analysis
by VulDB Data Team • 12/29/2021
The vulnerability identified as CVE-2013-2277 represents a critical buffer over-read condition within the FFmpeg multimedia framework's H.264 video decoding implementation. This flaw exists in the ff_h264_decode_seq_parameter_set function located in the h264_ps.c file, which processes sequence parameter sets for H.264 video streams. The vulnerability specifically arises from insufficient validation of the relationship between luma depth and chroma depth parameters within the video stream structure. When processing malformed H.264 data containing crafted sequence parameter set values, the decoder fails to properly validate that the luma and chroma depth values maintain appropriate mathematical relationships, leading to potential out-of-bounds memory access patterns. This issue falls under CWE-129, which addresses insufficient validation of length fields, and represents a classic buffer over-read vulnerability that can result in application instability. The vulnerability affects FFmpeg versions prior to 1.1.3, making it particularly significant given the widespread adoption of FFmpeg in multimedia processing applications, streaming platforms, and content delivery networks.
The technical exploitation of this vulnerability occurs when maliciously crafted H.264 video streams contain sequence parameter sets with invalid depth relationships that cause the decoder to access memory locations beyond the allocated buffer boundaries. The function processes the sequence parameter set information without adequately validating that the luma and chroma depth values are consistent with each other and with the expected H.264 specification parameters. This validation gap allows attackers to manipulate the depth parameters in such a way that subsequent array indexing operations reference memory locations outside the intended buffer boundaries. The out-of-bounds access can result in memory corruption that manifests as application crashes, denial of service conditions, or potentially more severe consequences depending on the memory layout and execution context. The vulnerability's impact extends beyond simple denial of service as the memory corruption patterns could potentially be leveraged for more sophisticated attacks, though the primary concern remains the stability and availability of affected systems. This type of vulnerability aligns with ATT&CK technique T1203, which involves exploiting input validation flaws in multimedia processing components.
The operational impact of CVE-2013-2277 is substantial across various deployment scenarios where FFmpeg is utilized for video processing and streaming operations. Systems that process untrusted video content, including media servers, content delivery networks, video transcoding platforms, and streaming applications, become vulnerable to remote denial of service attacks. Attackers can craft malicious H.264 streams that, when processed by vulnerable FFmpeg implementations, will cause the application to crash or become unresponsive, effectively rendering the service unavailable to legitimate users. The vulnerability's remote exploitability means that attackers do not require local access to the system, making it particularly dangerous for publicly accessible services. Organizations using FFmpeg in their multimedia pipelines face significant risk as this vulnerability can be triggered through normal video processing workflows, potentially affecting streaming services, video conferencing systems, and content management platforms. The widespread use of FFmpeg across different software ecosystems means that the vulnerability's potential attack surface is extensive, affecting everything from consumer applications to enterprise multimedia infrastructure. The vulnerability's classification under CWE-129 highlights the fundamental nature of the problem as a failure to validate input parameters that directly control memory access patterns, making it a critical security concern for any system processing multimedia content.