CVE-2011-3936 in FFmpeg
Summary
by MITRE
The dv_extract_audio function in libavcodec in FFmpeg 0.7.x before 0.7.12 and 0.8.x before 0.8.11 and in Libav 0.5.x before 0.5.9, 0.6.x before 0.6.6, 0.7.x before 0.7.5, and 0.8.x before 0.8.1 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via a crafted DV file.
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Analysis
by VulDB Data Team • 12/08/2021
The vulnerability identified as CVE-2011-3936 represents a critical out-of-bounds read flaw within the dv_extract_audio function of multimedia processing libraries. This issue affects widely used open source libraries FFmpeg and Libav, which serve as foundational components for video and audio processing across numerous applications and systems. The vulnerability stems from inadequate input validation mechanisms within the DV (Digital Video) file parsing functionality, specifically when processing audio data extracted from DV format files. The flaw manifests when the application attempts to read memory locations beyond the allocated buffer boundaries during audio extraction operations, leading to unpredictable behavior and system instability.
The technical exploitation of this vulnerability occurs through the manipulation of crafted DV files that contain malformed audio data structures. When the dv_extract_audio function processes such malicious input, it fails to properly validate array indices or buffer limits before accessing audio sample data. This results in the application reading beyond the intended memory boundaries, causing memory corruption that ultimately leads to application crashes and system instability. The vulnerability is particularly concerning because it can be triggered remotely through web-based media processing systems, making it an attractive target for attackers seeking to disrupt services or potentially escalate privileges. According to CWE classification, this represents a CWE-125: Out-of-bounds Read vulnerability, which falls under the broader category of memory safety issues that have historically been exploited for privilege escalation and denial of service attacks.
The operational impact of CVE-2011-3936 extends far beyond simple application crashes, as it affects systems that process multimedia content from untrusted sources. Media processing servers, content management systems, and web applications that utilize FFmpeg or Libav for video conversion and audio extraction are all at risk. The vulnerability can be exploited in various attack scenarios including web application exploitation, email attachment processing, and content delivery network attacks. When exploited successfully, the out-of-bounds read can cause complete application termination, potentially leading to service disruption for legitimate users. In more sophisticated attack vectors, attackers may be able to leverage this vulnerability as a stepping stone for further exploitation, especially when combined with other memory corruption vulnerabilities. The attack surface is extensive given that FFmpeg and Libav are integrated into countless applications including media players, streaming platforms, content management systems, and server-side processing tools.
Mitigation strategies for CVE-2011-3936 primarily focus on immediate software updates and patches provided by the respective vendors. Organizations should prioritize upgrading to patched versions of FFmpeg 0.7.12, 0.8.11, or Libav versions 0.5.9, 0.6.6, 0.7.5, and 0.8.1, as these releases contain the necessary fixes to address the out-of-bounds read conditions. Additionally, implementing input validation measures and sandboxing techniques can provide additional defense-in-depth layers. System administrators should consider implementing strict file format validation and limiting the processing of untrusted media files through network-based filters and content inspection systems. The vulnerability aligns with ATT&CK technique T1203: Exploitation for Client Execution, as it enables attackers to cause remote code execution through media processing applications. Organizations should also consider network segmentation and monitoring for unusual processing patterns that might indicate exploitation attempts. Regular vulnerability assessments and security audits of multimedia processing systems are essential to identify and remediate similar vulnerabilities before they can be exploited by adversaries.