CVE-2021-32265 in Bento4
Summary
by MITRE • 09/20/2021
An issue was discovered in Bento4 through v1.6.0-637. A global-buffer-overflow exists in the function AP4_MemoryByteStream::WritePartial() located in Ap4ByteStream.cpp. It allows an attacker to cause code execution or information disclosure.
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Analysis
by VulDB Data Team • 09/29/2021
The vulnerability identified as CVE-2021-32265 represents a critical security flaw within the Bento4 multimedia framework version 1.6.0-637 and earlier. This issue manifests as a global buffer overflow in the AP4_MemoryByteStream::WritePartial() function, which resides in the Ap4ByteStream.cpp source file. The Bento4 library serves as a comprehensive multimedia framework designed for processing and manipulating various digital media formats, making it a widely used component in content delivery systems, streaming platforms, and media processing applications across multiple industries.
The technical nature of this vulnerability stems from improper bounds checking within the memory byte stream handling mechanism. When the WritePartial() function processes data writes to memory streams, it fails to validate the size of data being written against the allocated buffer boundaries. This oversight creates a condition where an attacker can supply maliciously crafted input data that exceeds the intended buffer limits, resulting in memory corruption. The buffer overflow occurs at a global level within the memory management system, making it particularly dangerous as it can affect the entire application's memory space rather than just a localized segment.
The operational impact of this vulnerability extends beyond simple memory corruption, presenting attackers with opportunities for remote code execution and information disclosure. When an attacker successfully exploits this buffer overflow, they can manipulate the program's execution flow by overwriting critical memory locations such as return addresses, function pointers, or control data structures. This capability enables arbitrary code execution on the target system, potentially allowing attackers to gain full control over the affected application or system. Additionally, the information disclosure aspect means that sensitive data from memory locations adjacent to the vulnerable buffer could be read and potentially exposed to unauthorized parties, compromising system confidentiality and potentially revealing credentials, encryption keys, or other sensitive information.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in memory management operations. From an adversarial perspective, this flaw maps to several ATT&CK tactics including execution through command and script injection, privilege escalation via memory corruption techniques, and defense evasion through the use of memory manipulation to avoid detection. The attack surface is particularly concerning for applications that process untrusted media files or stream content from external sources, as these scenarios provide natural entry points for exploitation. Organizations utilizing Bento4 in production environments face significant risk, especially those in sectors where media processing is critical such as streaming services, content delivery networks, and digital rights management systems.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected Bento4 installations to version 1.6.0-638 or later, which contains the necessary fixes for the buffer overflow condition. Additionally, implementing runtime protections such as address space layout randomization, stack canaries, and heap metadata protection can provide defense-in-depth measures. Input validation should be strengthened at all levels of the application stack, particularly for any data processing that involves memory byte stream operations. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the media processing pipeline. System monitoring should be enhanced to detect anomalous memory access patterns or unexpected code execution that might indicate exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation, while maintaining comprehensive logging and incident response procedures to quickly identify and contain any exploitation activities.