CVE-2020-13428 in VLC Media Player
Summary
by MITRE
A heap-based buffer overflow in the hxxx_AnnexB_to_xVC function in modules/packetizer/hxxx_nal.c in VideoLAN VLC media player through 3.2.8 for iOS, and through 3.0.10 for macOS, allows remote attackers to cause a denial of service (application crash) or execute arbitrary code via a crafted H.264 Annex-B video (.avi for example) file.
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Analysis
by VulDB Data Team • 10/22/2020
The vulnerability CVE-2020-13428 represents a critical heap-based buffer overflow affecting VideoLAN VLC media player across multiple platforms including iOS and macOS. This flaw exists within the hxxx_AnnexB_to_xVC function located in the modules/packetizer/hxxx_nal.c file, which processes H.264 Annex-B video streams. The vulnerability specifically targets the handling of video files with the .avi extension that contain crafted H.264 Annex-B data, creating a dangerous condition where malicious input can trigger unpredictable behavior in the media player application.
The technical implementation of this vulnerability stems from insufficient bounds checking during the conversion process of H.264 Annex-B format data to xVC format within VLC's packetizer module. When processing maliciously crafted video files, the function fails to properly validate the size and structure of incoming data, leading to memory corruption that manifests as a heap-based buffer overflow. This condition allows attackers to overwrite adjacent memory locations, potentially corrupting critical program data or execution pointers. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the heap-based nature indicates more complex memory manipulation capabilities that can be exploited for more sophisticated attacks.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to include potential remote code execution capabilities. Attackers can leverage this vulnerability to cause application crashes that result in denial of service, or more critically, execute arbitrary code on affected systems. The attack vector requires a victim to open a specially crafted .avi file containing malicious H.264 Annex-B data, making this a user-initiated attack that could occur through phishing emails, malicious websites, or compromised media sharing platforms. The vulnerability affects both iOS and macOS versions of VLC, indicating a widespread impact across Apple's ecosystem and highlighting the critical nature of this flaw in media processing applications.
Mitigation strategies for CVE-2020-13428 should prioritize immediate patching of affected VLC versions, with users upgrading to versions beyond 3.2.8 for iOS and 3.0.10 for macOS. System administrators should implement network-level controls to block suspicious video file types and monitor for unusual media processing activity. The vulnerability demonstrates the importance of proper input validation and memory safety practices in multimedia processing libraries, aligning with ATT&CK technique T1203 for legitimate credential use and T1059 for command and scripting interpreter usage. Organizations should also consider implementing sandboxing mechanisms for media processing applications to limit potential damage from successful exploitation attempts, while maintaining regular security updates to address similar vulnerabilities in third-party media libraries and codecs.