CVE-2021-31258 in GPAC
Summary
by MITRE • 04/20/2021
The gf_isom_set_extraction_slc 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.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/23/2021
The vulnerability identified as CVE-2021-31258 resides within the GPAC media processing library version 1.0.1, specifically within the gf_isom_set_extraction_slc function. This flaw represents a critical denial of service condition that can be exploited through carefully crafted MP4 files processed by the MP4Box command-line utility. The vulnerability manifests when the application attempts to handle malformed input files that trigger a NULL pointer dereference during the extraction process, effectively causing the application to crash and terminate unexpectedly. Such a condition severely impacts the reliability and availability of media processing workflows that depend on GPAC for handling multimedia content.
The technical implementation of this vulnerability stems from inadequate input validation within the gf_isom_set_extraction_slc function, which fails to properly check for null references before attempting to access memory locations. When processing specially crafted MP4 files, the function encounters a scenario where a pointer expected to contain valid data remains uninitialized or explicitly set to NULL, leading to an immediate crash upon dereferencing. This behavior aligns with CWE-476, which categorizes NULL pointer dereference as a common weakness in software design that can result in application instability and denial of service conditions. The vulnerability specifically affects the MP4Box utility's ability to parse and process media files, creating a pathway for attackers to disrupt legitimate media processing operations through crafted file inputs.
From an operational perspective, this vulnerability presents significant risks to organizations that rely on GPAC for media processing tasks, particularly in environments where automated workflows or batch processing systems are employed. The denial of service condition can be triggered remotely through file upload mechanisms or by processing maliciously crafted media files, potentially allowing attackers to disrupt services or cause system downtime. The impact extends beyond simple application crashes, as it can be leveraged to create persistent availability issues in media processing pipelines, affecting content delivery networks, streaming services, and other systems that depend on reliable media handling capabilities. This vulnerability particularly affects systems where GPAC is integrated into larger software ecosystems, as the crash can propagate through dependent services and potentially cause cascading failures in media processing infrastructure.
Organizations should implement immediate mitigations including updating to GPAC versions that have addressed this vulnerability, typically those released after the vulnerability disclosure. Network-based protections can be implemented through file validation mechanisms that scan for known malicious patterns in media files before processing, though this approach may not prevent all variants of the attack. Input validation should be strengthened at all levels of the processing pipeline to ensure that malformed files are rejected before reaching the vulnerable function. Additionally, system administrators should monitor for unusual application behavior or crash patterns that may indicate exploitation attempts. The mitigation strategy should align with ATT&CK technique T1499.004, which focuses on avoiding or evading detection through application crash prevention and system stability measures. Regular security assessments and vulnerability scanning should be conducted to identify other potential entry points within the media processing stack that may present similar risks.