CVE-2021-32437 in GPAC
Summary
by MITRE • 08/12/2021
The gf_hinter_finalize function in GPAC 1.0.1 allows attackers to cause a denial of service (NULL pointer dereference) via a crafted file in the MP4Box command.
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Analysis
by VulDB Data Team • 08/17/2021
The vulnerability identified as CVE-2021-32437 resides within the GPAC multimedia framework version 1.0.1, specifically within the gf_hinter_finalize function. This flaw represents a classic null pointer dereference issue that can be exploited by malicious actors to disrupt the normal operation of affected systems. The vulnerability manifests when the MP4Box command processes a specially crafted file, demonstrating how seemingly benign file handling operations can become vectors for system disruption. The GPAC framework serves as a comprehensive multimedia solution for encoding, decoding, and processing various video and audio formats, making this vulnerability particularly concerning for multimedia processing environments.
The technical implementation of this vulnerability stems from inadequate input validation within the gf_hinter_finalize function, which fails to properly check for null pointer references before attempting to dereference memory locations. When a crafted MP4 file is processed through MP4Box, the function encounters unexpected null values in its internal data structures, leading to an immediate system crash. This type of vulnerability aligns with CWE-476, which specifically addresses null pointer dereference conditions in software implementations. The flaw operates at the level of memory management and pointer validation, where the application assumes certain memory locations contain valid data without proper verification mechanisms.
The operational impact of CVE-2021-32437 extends beyond simple service disruption, as it can be leveraged for broader denial of service attacks against multimedia processing systems. Attackers can craft malicious files that, when processed by vulnerable GPAC installations, will cause the MP4Box command to terminate unexpectedly, potentially leading to complete system unavailability. This vulnerability particularly affects environments where GPAC is used for automated multimedia processing, content delivery networks, or any system that relies on MP4Box for video file manipulation. The attack vector requires minimal sophistication, as it only necessitates the creation of a malformed MP4 file, making it accessible to threat actors with basic technical knowledge.
Organizations utilizing GPAC 1.0.1 should prioritize immediate mitigation strategies to protect their systems from exploitation. The primary recommended action involves upgrading to a patched version of the GPAC framework where the null pointer dereference has been addressed through proper input validation and memory safety checks. System administrators should also implement file validation procedures that scan for potentially malicious MP4 files before processing, particularly in automated environments where untrusted input is common. From a defensive perspective, this vulnerability demonstrates the importance of robust input sanitization and memory safety practices in multimedia frameworks, aligning with ATT&CK technique T1499.001 which covers network denial of service attacks. Additionally, implementing proper error handling and graceful degradation mechanisms can help minimize the impact of such vulnerabilities in production environments, ensuring that system failures do not cascade into complete service outages.