CVE-2012-2793 in FFmpeg
Summary
by MITRE
Unspecified vulnerability in the lag_decode_zero_run_line function in libavcodec/lagarith.c in FFmpeg before 0.11, and Libav 0.7.x before 0.7.7 and 0.8.x before 0.8.4, has unknown impact and attack vectors related to "too many zeros."
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Analysis
by VulDB Data Team • 12/13/2021
The vulnerability identified as CVE-2012-2793 represents a critical security flaw affecting multimedia processing libraries within the FFmpeg and Libav ecosystems. This issue resides in the lag_decode_zero_run_line function located in libavcodec/lagarith.c, where the problematic behavior manifests when processing encoded data containing excessive sequences of zero values. The vulnerability affects multiple versions of both FFmpeg and Libav, specifically targeting releases prior to 0.11 for FFmpeg and various 0.7.x and 0.8.x releases of Libav, indicating a widespread impact across different software versions and development branches.
The technical nature of this vulnerability stems from inadequate input validation within the lagarith codec decoding process. When the lag_decode_zero_run_line function encounters data streams with an excessive number of consecutive zero values, the decoding algorithm fails to properly handle the boundary conditions, leading to potential memory corruption or unexpected behavior. This type of vulnerability falls under the category of buffer over-read or improper input handling, which can result in arbitrary code execution or denial of service conditions. The unspecified impact and attack vectors suggest that the vulnerability may manifest in multiple ways depending on the specific data patterns and system configurations encountered during processing.
The operational impact of CVE-2012-2793 extends beyond simple functionality degradation, potentially enabling remote code execution attacks when vulnerable software processes maliciously crafted multimedia files. Systems utilizing affected versions of FFmpeg or Libav for video processing, streaming, or transcoding operations become susceptible to exploitation through crafted media files that trigger the problematic zero run sequence handling. This vulnerability particularly affects content management systems, media servers, and applications that automatically process user-uploaded video content without proper sanitization. The attack surface includes web applications, media processing pipelines, and any system that relies on these libraries for handling multimedia content, making it a significant concern for organizations managing digital media workflows.
Mitigation strategies for this vulnerability require immediate software updates to versions that contain the necessary patches and fixes. Organizations should prioritize upgrading to FFmpeg 0.11 or later, and Libav versions 0.7.7, 0.8.4, or newer, which address the specific handling of zero run sequences in the lagarith decoder. Additionally, implementing input validation measures such as pre-processing media files through trusted sanitization tools, employing sandboxed execution environments for multimedia processing, and deploying network-based intrusion detection systems can provide additional layers of protection. The vulnerability aligns with CWE-129, which addresses insufficient input validation, and may be categorized under ATT&CK technique T1203 for exploitation of software vulnerabilities in media processing applications. Security monitoring should focus on detecting unusual patterns in media file processing, particularly when handling files with extended zero sequences, as these may indicate attempted exploitation of the vulnerability.