CVE-2017-15186 in FFmpeg
Summary
by MITRE
Double free vulnerability in FFmpeg 3.3.4 and earlier allows remote attackers to cause a denial of service via a crafted AVI file.
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Analysis
by VulDB Data Team • 01/20/2021
The CVE-2017-15186 vulnerability represents a critical double free condition within the FFmpeg multimedia framework version 3.3.4 and earlier, exposing systems to remote denial of service attacks through maliciously crafted AVI file inputs. This vulnerability resides in the video processing pipeline where FFmpeg handles AVI container format parsing, specifically affecting the memory management routines responsible for handling video stream data. The flaw manifests when the software processes malformed AVI files containing crafted data structures that trigger improper memory deallocation sequences during video frame processing.
The technical implementation of this vulnerability stems from inadequate input validation and memory management practices within FFmpeg's AVI demuxer component. When processing a specially constructed AVI file, the software's parser encounters malformed data that causes it to allocate memory for video frame buffers and subsequently attempt to free the same memory locations multiple times. This double free scenario occurs during the handling of video stream headers and frame data structures, where the memory allocation and deallocation logic fails to properly track allocated resources. The vulnerability is classified under CWE-415 as an improper free condition, where the same memory location is freed twice, potentially leading to memory corruption that can be exploited for denial of service attacks.
The operational impact of this vulnerability extends beyond simple service disruption, as remote attackers can leverage this weakness to cause sustained denial of service against systems processing AVI content. Systems utilizing FFmpeg for video transcoding, streaming, or playback operations become vulnerable when they accept untrusted AVI files from external sources. The attack vector requires only a single malicious AVI file to be processed by an affected FFmpeg instance, making it particularly dangerous for web applications, content management systems, and media processing servers that automatically handle user-uploaded video content. The vulnerability can be exploited across various deployment scenarios including web servers, media streaming platforms, and content delivery networks that rely on FFmpeg for video processing.
Mitigation strategies for CVE-2017-15186 should prioritize immediate software updates to FFmpeg versions 3.3.5 or later, where the double free condition has been resolved through improved memory management and input validation. Organizations should implement strict input validation procedures for all AVI file processing, including file format verification and size limitations to prevent exploitation. Network segmentation and access controls should be enforced to limit exposure of FFmpeg processing services to untrusted inputs. Security monitoring should include detection of anomalous memory usage patterns and potential exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499.004 for network denial of service, with potential for lateral movement through compromised media processing services. Additionally, implementing sandboxing mechanisms for video file processing and regular security assessments of multimedia handling components can significantly reduce the risk of exploitation. Organizations should also consider deploying intrusion detection systems capable of identifying patterns associated with AVI file processing anomalies that may indicate exploitation attempts.