CVE-2021-35307 in Bento4
Summary
by MITRE • 08/06/2021
An issue was discovered in Bento4 through v1.6.0-636. A NULL pointer dereference exists in the AP4_DescriptorFinder::Test component located in /Core/Ap4Descriptor.h. It allows an attacker to cause a denial of service (DOS).
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Analysis
by VulDB Data Team • 08/10/2021
The vulnerability identified as CVE-2021-35307 represents a critical null pointer dereference flaw within the Bento4 media processing library version 1.6.0-636 and earlier. This issue resides in the AP4_DescriptorFinder::Test component, which is part of the Core/Ap4Descriptor.h file structure. The flaw manifests when the software attempts to access a null pointer reference during descriptor validation processes, creating a potential pathway for malicious actors to disrupt system operations through deliberate exploitation of this memory access violation.
The technical implementation of this vulnerability stems from inadequate input validation within the AP4_DescriptorFinder::Test method, which fails to properly handle cases where descriptor data structures may be null or improperly initialized. When processing media files containing malformed or crafted descriptor information, the system attempts to dereference a null pointer without proper null checks, leading to an immediate crash of the application or process. This behavior aligns with CWE-476, which specifically addresses null pointer dereference conditions that can result in application instability and denial of service scenarios.
From an operational impact perspective, this vulnerability presents a significant risk to systems relying on Bento4 for media processing tasks, particularly in environments where untrusted input is processed such as content delivery networks, media servers, or automated processing pipelines. Attackers can craft specially formatted media files or descriptor data that triggers the null pointer dereference, resulting in service disruption and potential denial of service conditions that can affect legitimate users and system availability. The vulnerability's exploitation requires minimal effort and can be automated, making it particularly dangerous in production environments where continuous service availability is critical.
The attack surface for this vulnerability extends across various security frameworks and threat models, particularly aligning with ATT&CK technique T1499.004 which covers network denial of service attacks through application-level flaws. Organizations utilizing Bento4 for content processing should consider this vulnerability as part of their broader application security posture, especially in environments where media files are processed from external sources or user uploads. The lack of proper input sanitization and validation in the descriptor handling component creates a persistent risk that can be exploited across multiple deployment scenarios including web applications, media processing services, and content management systems.
Mitigation strategies should focus on immediate patching of the Bento4 library to version 1.6.0-637 or later, where the null pointer dereference has been addressed through proper input validation and null pointer checks. Additionally, implementing defensive programming practices such as input sanitization, robust error handling, and comprehensive testing of media file processing pipelines can help prevent exploitation of similar vulnerabilities. Organizations should also consider implementing monitoring and alerting mechanisms to detect potential exploitation attempts and maintain detailed logs of media processing activities to identify anomalous behavior that may indicate attempted exploitation of this or related vulnerabilities.