CVE-2017-11719 in FFmpeg
Summary
by MITRE
The dnxhd_decode_header function in libavcodec/dnxhddec.c in FFmpeg through 3.3.2 allows remote attackers to cause a denial of service (out-of-array access) or possibly have unspecified other impact via a crafted DNxHD file.
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Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-11719 represents a critical buffer over-read flaw within the FFmpeg multimedia framework's DNxHD decoder component. This issue resides in the dnxhd_decode_header function located in libavcodec/dnxhddec.c, affecting FFmpeg versions through 3.3.2. The flaw manifests when processing specially crafted DNxHD video files, which are professional video formats commonly used in broadcast and post-production environments. The vulnerability stems from insufficient input validation and bounds checking during header parsing operations, creating a scenario where maliciously constructed file headers can trigger unauthorized memory access patterns.
The technical exploitation of this vulnerability occurs through improper handling of array indexing during the decoding process. When the dnxhd_decode_header function processes malformed DNxHD headers, it fails to properly validate the size parameters and array bounds before accessing memory locations. This allows attackers to craft video files that contain crafted header values which, when processed by the vulnerable FFmpeg library, result in out-of-bounds memory reads. The vulnerability is classified as a buffer over-read according to CWE-125 and represents a specific instance of improper input validation that can lead to denial of service conditions or potentially more severe consequences depending on the execution context.
From an operational perspective, this vulnerability presents significant risks to systems that process user-uploaded video content or handle multimedia files from untrusted sources. The impact extends beyond simple denial of service to potentially enabling more sophisticated attacks depending on the deployment environment. Systems utilizing FFmpeg for video processing, content management, or streaming services become vulnerable to remote exploitation when handling maliciously crafted DNxHD files. The vulnerability affects a wide range of applications including media servers, content delivery networks, and video processing pipelines that rely on FFmpeg's decoding capabilities. Organizations deploying these systems without proper input sanitization measures face potential service disruption and data integrity risks.
The mitigation strategies for CVE-2017-11719 primarily involve immediate version updates to FFmpeg 3.3.3 or later, which contain the necessary patches addressing the buffer over-read condition. System administrators should also implement input validation measures, including file format verification and size limiting for uploaded content, to reduce the attack surface. Additionally, deploying network segmentation and application whitelisting can help limit potential exploitation pathways. The vulnerability aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for privilege escalation and denial of service. Organizations should also consider implementing automated patch management processes and regular security assessments to identify and remediate similar vulnerabilities in their multimedia processing pipelines. The remediation approach should include comprehensive testing of updated libraries in staging environments to ensure compatibility with existing applications while addressing the identified security concerns.