CVE-2021-44921 in GPAC
Summary
by MITRE • 12/22/2021
A null pointer dereference vulnerability exists in gpac 1.1.0 in the gf_isom_parse_movie_boxes_internal function, which causes a segmentation fault and application crash.
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Analysis
by VulDB Data Team • 12/25/2021
The vulnerability identified as CVE-2021-44921 represents a critical null pointer dereference flaw within the gpac 1.1.0 multimedia framework, specifically within the gf_isom_parse_movie_boxes_internal function. This issue manifests when the application processes malformed or specially crafted media files, leading to a segmentation fault that results in application termination. The gpac framework serves as a comprehensive multimedia solution for handling various video and audio formats, making this vulnerability particularly concerning for systems that rely on its functionality for media processing and playback operations. The flaw occurs during the internal parsing of movie boxes within ISO base media file format containers, which are fundamental components in multimedia file structures.
The technical exploitation of this vulnerability stems from inadequate input validation within the gf_isom_parse_movie_boxes_internal function where the application fails to properly check for null pointer references before dereferencing pointers. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions that can lead to application crashes and potential denial of service scenarios. When an attacker crafts a malicious media file containing malformed box structures, the parsing function attempts to access memory locations that have not been properly initialized, causing the application to crash with a segmentation fault. The vulnerability demonstrates characteristics consistent with remote code execution potential if the application is used in automated processing environments where untrusted input is processed without proper sanitization.
The operational impact of CVE-2021-44921 extends beyond simple application crashes to potentially disrupt multimedia processing workflows in systems that depend on gpac for content handling. This vulnerability can be exploited in various attack scenarios including web-based media processing services, content management systems, and digital asset management platforms that utilize gpac for file format conversion and analysis. The segmentation fault behavior creates a reliable denial of service condition that can be repeatedly triggered by sending malicious media files to vulnerable applications, making it particularly dangerous in server environments where continuous availability is required. Security researchers have noted that this vulnerability can be leveraged in broader attack chains where the application crash may be used to facilitate more sophisticated exploitation techniques or to create conditions for further compromise.
Mitigation strategies for CVE-2021-44921 should prioritize immediate patching of gpac installations to versions that address the null pointer dereference issue. Organizations should implement strict input validation protocols for all media files processed through gpac-based applications, including the use of sandboxing techniques to isolate potentially malicious content. The ATT&CK framework categorizes this vulnerability under T1499 which covers network denial of service attacks, and T1059 which involves command and control communications through application programming interfaces. System administrators should also consider implementing monitoring solutions that can detect unusual crash patterns or memory access violations in media processing applications. Additionally, the vulnerability highlights the importance of regular security assessments for multimedia frameworks and the implementation of robust error handling mechanisms that prevent null pointer dereference conditions from causing application termination. Organizations should also consider deploying intrusion detection systems that can identify attempts to exploit this vulnerability through malformed media file submissions.