CVE-2021-33499 in Infinity
Summary
by MITRE • 01/15/2022
Pexip Infinity before 26 allows remote denial of service because of missing H.264 input validation (issue 2 of 2).
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/19/2022
The vulnerability identified as CVE-2021-33499 affects Pexip Infinity versions prior to 26, representing a critical remote denial of service flaw stemming from inadequate H.264 input validation. This issue constitutes the second of two related problems within the Pexip Infinity platform, highlighting a significant weakness in the system's media processing capabilities. The vulnerability specifically targets the handling of H.264 video streams, which are commonly used in video conferencing and communication platforms. When maliciously crafted H.264 input data is processed by the affected system, it can trigger unexpected behavior that leads to system instability and complete service disruption. The root cause of this vulnerability aligns with CWE-20, which describes improper input validation, and more specifically with CWE-400, relating to resource exhaustion through uncontrolled inputs. This flaw enables attackers to exploit the system's media processing pipeline without requiring authentication or prior access to the platform.
The operational impact of CVE-2021-33499 extends beyond simple service interruption, as it can potentially affect entire communication infrastructures that rely on Pexip Infinity for video conferencing and collaboration services. Organizations using affected versions may experience complete denial of service for their video conferencing capabilities, disrupting critical business operations and communication flows. The vulnerability's remote nature means that attackers can exploit it from anywhere on the network, making it particularly dangerous for organizations with exposed systems. In enterprise environments where video conferencing is essential for remote work, training sessions, and client meetings, this vulnerability could result in significant operational downtime and productivity losses. The attack surface is further expanded by the fact that H.264 is a widely used video codec, making the vulnerability potentially exploitable across multiple communication platforms that utilize this standard.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1499.004 for network denial of service and T1203 for exploitation for execution. The flaw enables attackers to leverage the media processing capabilities of the system as a vector for service disruption, potentially allowing for more sophisticated attacks if combined with other vulnerabilities. Security professionals should note that the vulnerability's impact is not limited to immediate service interruption but could also serve as a precursor to more advanced attacks that exploit the same underlying input validation weaknesses. The lack of proper input sanitization means that attackers can craft malicious H.264 streams that cause memory corruption, resource exhaustion, or other system instability conditions that result in complete service failure.
Organizations should prioritize immediate remediation by upgrading to Pexip Infinity version 26 or later, which includes the necessary input validation patches for H.264 streams. Network segmentation and access controls should be implemented to limit exposure of the affected system to untrusted networks. Monitoring systems should be enhanced to detect unusual patterns in media stream processing that could indicate exploitation attempts. Additionally, implementing rate limiting and input validation at network boundaries can provide defense-in-depth against similar vulnerabilities. Security teams should also conduct thorough vulnerability assessments of their communication infrastructure to identify other potential input validation weaknesses that could be exploited using similar techniques. The remediation process should include comprehensive testing to ensure that the patch does not introduce compatibility issues with existing video conferencing workflows while maintaining the system's ability to handle legitimate H.264 streams.