CVE-2020-23331 in Bento4
Summary
by MITRE • 08/18/2021
An issue was discovered in Bento4 version 06c39d9. A NULL pointer dereference exists in the AP4_DecoderConfigDescriptor::WriteFields 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 • 08/19/2021
The vulnerability identified as CVE-2020-23331 represents a critical null pointer dereference flaw within the Bento4 media processing library version 06c39d9. This issue specifically affects the AP4_DecoderConfigDescriptor::WriteFields component, which is responsible for handling decoder configuration descriptors in advanced video and audio stream processing. The flaw exists in the Core/Ap4Descriptor.h file, indicating a fundamental weakness in how the library manages descriptor fields during write operations. This type of vulnerability falls under CWE-476, which categorizes null pointer dereference conditions that can lead to system instability and service disruption. The Bento4 library is widely used for creating and manipulating multimedia content, particularly in streaming applications, making this vulnerability particularly concerning for organizations relying on its functionality.
The technical implementation of this vulnerability stems from improper validation of input parameters within the WriteFields method of the AP4_DecoderConfigDescriptor class. When processing malformed or specially crafted media files, the component fails to properly check for null references before attempting to dereference pointers, leading to a crash condition. This behavior aligns with the ATT&CK technique T1499.004, which involves network denial of service attacks through resource exhaustion or system instability. The null pointer dereference occurs during the descriptor field writing process, suggesting that attackers can manipulate media file structures to trigger the vulnerability when the library attempts to serialize or process specific decoder configuration data. The flaw essentially creates an execution path where the program attempts to access memory through a null pointer reference, causing an immediate system termination.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can be exploited to disrupt services that depend on Bento4 for media processing. Organizations utilizing this library in content delivery networks, streaming platforms, or media processing pipelines may experience complete service outages when maliciously crafted media files are processed. The vulnerability's exploitation does not require elevated privileges, making it particularly dangerous as any user capable of uploading or processing media content could trigger the flaw. This represents a significant risk for web applications, media servers, and content management systems where user-uploaded media is processed through the affected library. The potential for cascading failures increases when considering that Bento4 is often integrated into larger software ecosystems, meaning a single vulnerable component can compromise entire service architectures.
Mitigation strategies for CVE-2020-23331 should prioritize immediate patching of the Bento4 library to version containing the fixed implementation of the AP4_DecoderConfigDescriptor::WriteFields method. Organizations should implement input validation and sanitization measures at the application level to prevent malformed media files from reaching the vulnerable library components. Additionally, deploying network segmentation and access controls can limit the potential impact of exploitation attempts. The fix should include proper null pointer checks before any field dereference operations, ensuring that all pointer references are validated against null values before access. Security monitoring should be enhanced to detect unusual patterns in media processing activities that might indicate exploitation attempts. Organizations should also consider implementing automated vulnerability scanning processes that can identify systems running vulnerable versions of the Bento4 library and prioritize remediation efforts accordingly.