^{CVE-2021-27565:}Infinite Loop Vulnerability in InterNiche NicheStack Web Server

Overview

This vulnerability (CVE-2021-27565) affects the InterNiche NicheStack TCP/IP stack, which is widely used in operational technology (OT) and industrial control systems. The issue occurs in the web server component where a programming error causes the system to enter an infinite loop when processing certain valid HTTP requests. The vulnerability is classified as CWE-835 (Infinite Loop), allowing attackers to remotely trigger a denial of service condition without requiring authentication. Since NicheStack is embedded in numerous industrial devices, this vulnerability potentially impacts critical infrastructure across multiple sectors.

Remediation

Organizations should take the following steps to mitigate this vulnerability:

1. Update to the latest version of NicheStack if available from your device vendor.
2. If updates are not available, implement network segmentation to restrict access to affected devices.
3. Use firewalls or access control lists to block unexpected HTTP requests to vulnerable devices.
4. Monitor network traffic for suspicious HTTP requests targeting industrial devices.
5. Contact your device manufacturer to confirm if your specific implementation is vulnerable and to obtain specific patching guidance.
6. Consider implementing intrusion detection systems that can identify exploitation attempts of this vulnerability.

References

1. Forescout Research: "New Critical Operational Technology Vulnerabilities Found on NicheStack" - https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/
2. HCC Embedded (current owner of InterNiche technologies) - https://www.hcc-embedded.com/
3. Information about InterNiche products - https://www.hcc-embedded.com/about/about-interniche
4. CERT Vulnerability Note VU#608209 - https://www.kb.cert.org/vuls/id/608209