CVE-2012-2784 in FFmpeg
Summary
by MITRE
Unspecified vulnerability in the decode_pic function in libavcodec/cavsdec.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 "width/height changing in CAVS," a different vulnerability than CVE-2012-2777.
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Analysis
by VulDB Data Team • 12/13/2021
The vulnerability identified as CVE-2012-2784 represents a critical security flaw within the FFmpeg multimedia processing library that affects multiple versions of both FFmpeg and its fork Libav. This issue resides in the decode_pic function located within the libavcodec/cavsdec.c file, which handles the decoding of CAVS (China Audio Video Standard) encoded video streams. The vulnerability specifically relates to improper handling of width and height parameters during the decoding process, creating a potential pathway for malicious actors to exploit the system through crafted video content. The flaw is distinct from CVE-2012-2777, indicating it operates through different code paths and attack vectors, yet shares the same underlying category of video decoding vulnerabilities.
The technical nature of this vulnerability stems from insufficient bounds checking and parameter validation within the CAVS decoder implementation. When processing video streams with changing width and height parameters, the decode_pic function fails to properly validate or constrain the dimensional values, potentially leading to memory corruption scenarios. This type of vulnerability falls under CWE-125, which describes "Out-of-bounds Read" conditions, and may also manifest as CWE-787, "Out-of-bounds Write," depending on the specific execution path taken during exploitation. The vulnerability's impact becomes particularly severe when considering that CAVS is a video codec standard used in various multimedia applications, making the attack surface broader than initially apparent.
The operational impact of CVE-2012-2784 extends beyond simple denial of service scenarios to potentially enable remote code execution in vulnerable systems. When applications utilizing FFmpeg or Libav for video processing encounter maliciously crafted CAVS streams with manipulated width and height parameters, the improper memory handling can result in buffer overflows, memory corruption, or arbitrary code execution. This vulnerability affects a wide range of applications including media players, streaming services, content management systems, and any software that processes video content through these libraries. The attack vectors are particularly concerning as they can be triggered through automated means when users view or download content from untrusted sources, making the exploitation relatively straightforward for threat actors.
Mitigation strategies for this vulnerability require immediate patching of affected software versions to ensure proper bounds checking and parameter validation within the CAVS decoder. System administrators should prioritize updating FFmpeg installations to version 0.11 or later, while Libav users must upgrade to versions 0.7.7 or 0.8.4 respectively. Additionally, implementing input validation measures at the application level can provide an additional layer of protection by sanitizing video parameters before they reach the underlying library functions. Network-based defenses should include content filtering mechanisms that can detect and block potentially malicious video streams, particularly those containing unusual width and height parameter combinations. The vulnerability also highlights the importance of maintaining up-to-date multimedia libraries and implementing proper security testing procedures during software development cycles to prevent similar issues from arising in future implementations. Organizations should also consider implementing runtime monitoring and anomaly detection systems to identify unusual memory access patterns that may indicate exploitation attempts, as this vulnerability aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python" and T1203 for "Exploitation for Client Execution" when considering the potential for remote code execution scenarios.