CVE-2021-34069 in tsMuxer
Summary
by MITRE • 06/24/2021
Divide-by-zero bug in tsMuxer 2.6.16 allows attackers to cause a Denial of Service (DoS) by running the application with a crafted file.
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Analysis
by VulDB Data Team • 06/26/2021
The vulnerability identified as CVE-2021-34069 represents a critical divide-by-zero error within tsMuxer version 2.6.16 that enables remote attackers to execute denial of service attacks through maliciously crafted input files. This issue resides in the media processing component of tsMuxer, a popular open-source tool used for muxing and demuxing various multimedia formats including mpeg2, h.264, and h.265 video streams. The flaw occurs when the application attempts to process specially constructed media files that contain malformed data structures leading to arithmetic exceptions during the parsing phase of the media file analysis.
The technical implementation of this vulnerability stems from inadequate input validation within the tsMuxer codebase where division operations are performed without proper checks for zero denominators. When processing media files, the application encounters specific patterns in the stream data that trigger division by zero conditions in the underlying mathematical calculations used for frame rate calculations, bit rate computations, or other temporal metadata processing functions. This divide-by-zero condition causes the application to crash or terminate unexpectedly, effectively rendering the service unavailable to legitimate users who might attempt to process valid media files through the same application.
From an operational perspective, this vulnerability presents a significant risk to systems that rely on tsMuxer for media processing workflows, particularly in automated environments where batch processing of media files occurs. Attackers can exploit this weakness by creating malicious media files that, when processed by tsMuxer, will cause the application to crash and restart repeatedly, leading to sustained denial of service conditions. The impact extends beyond simple application crashes as the vulnerability can be leveraged in automated attack scenarios where multiple malicious files are processed in sequence, potentially exhausting system resources or causing cascading failures in media processing pipelines. Organizations using tsMuxer in production environments face potential service interruptions that could affect content delivery networks, broadcast systems, or media processing servers that depend on this tool for their operations.
The vulnerability aligns with CWE-369, which specifically addresses the divide-by-zero weakness in software systems, and demonstrates how inadequate error handling can lead to service disruption. From an attacker's perspective, this represents a low-effort, high-impact vector that requires minimal technical expertise to exploit, making it particularly dangerous in environments where tsMuxer is used in automated processing workflows. The ATT&CK framework categorizes this vulnerability under the 'Execution' and 'Denial of Service' tactics, as it enables an attacker to disrupt normal application functionality and potentially gain unauthorized access to system resources through repeated exploitation attempts. Organizations should prioritize immediate patching of affected systems, implement proper input validation measures, and consider network-level restrictions to prevent unauthorized file processing that could trigger this vulnerability. Additionally, monitoring for unusual application termination patterns and implementing robust error handling mechanisms within media processing pipelines can help detect and mitigate exploitation attempts before they cause significant service disruption.
The broader implications of this vulnerability extend to media processing ecosystems where similar tools might share common code patterns or architectural weaknesses. This issue highlights the critical importance of robust input validation and error handling in multimedia processing applications, particularly those handling untrusted input files from external sources. System administrators should consider implementing sandboxed processing environments for media files, utilizing file format validation libraries, and establishing comprehensive monitoring protocols to detect potential exploitation attempts. The vulnerability also underscores the need for regular security assessments of open-source media processing tools, as these applications often form critical components in content delivery and broadcasting infrastructures where reliability and security are paramount considerations for maintaining service availability and preventing unauthorized disruption of media workflows.