CVE-2021-40564 in GPAC
Summary
by MITRE • 01/13/2022
A Segmentation fault caused by null pointer dereference vulnerability eists in Gpac through 1.0.2 via the avc_parse_slice function in av_parsers.c when using mp4box, which causes a denial of service.
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Analysis
by VulDB Data Team • 01/15/2022
The vulnerability identified as CVE-2021-40564 represents a critical segmentation fault resulting from a null pointer dereference within the Gpac multimedia framework version 1.0.2 and earlier. This flaw manifests specifically within the avc_parse_slice function located in the av_parsers.c source file, creating a condition where the application crashes when processing certain malformed mp4 files through the mp4box utility. The issue stems from inadequate input validation and error handling mechanisms that fail to properly check for null pointer conditions before attempting memory dereferencing operations. The vulnerability is particularly concerning as it can be exploited to trigger a denial of service condition, effectively rendering the affected system or application unavailable to legitimate users.
The technical implementation of this vulnerability demonstrates a classic null pointer dereference pattern that falls under CWE-476, which specifically addresses the use of null pointers in programming contexts where such references are not properly validated. When the avc_parse_slice function processes video data streams, it fails to validate whether certain pointers remain non-null before attempting to access memory locations they reference. This particular flaw exists in the context of video parsing operations where mp4box attempts to parse Advanced Video Coding (AVC) data streams, making it particularly dangerous for multimedia processing applications. The vulnerability is exploitable through crafted mp4 files that contain malformed slice data, causing the application to crash when attempting to parse these invalid structures.
From an operational perspective, this vulnerability poses significant risks to systems relying on Gpac for multimedia processing and video file manipulation. The denial of service impact means that legitimate users attempting to process or convert video files could inadvertently trigger the crash, potentially disrupting workflows in content creation, media servers, or any system where mp4box functionality is utilized. The vulnerability affects not only individual user systems but also enterprise environments where automated processing pipelines might be compromised by maliciously crafted video files. The exploitation requires minimal privileges and can be executed through simple file manipulation, making it particularly dangerous for unattended systems or automated processing environments.
Mitigation strategies for this vulnerability should focus on immediate patching of the Gpac framework to version 1.0.3 or later, where the null pointer dereference has been addressed through proper input validation and error handling mechanisms. System administrators should implement network-based filtering to prevent the processing of untrusted video files, particularly those from unknown sources or未经验证的用户上传。Additionally, deploying intrusion detection systems that can identify suspicious file processing patterns may help detect exploitation attempts. Organizations should also consider implementing sandboxing mechanisms for video file processing to isolate potential crashes and prevent them from affecting broader system operations. The vulnerability highlights the importance of proper memory management practices and input validation, particularly in multimedia processing libraries where complex data structures are parsed and manipulated. Security monitoring should include detection of segmentation fault patterns and process termination events that could indicate exploitation attempts.