Ngrok-free.app Malware Tunneling Abuse: Prevention Guide

This intelligence blog analyzes the rising misuse of tunneling/ingress-as-a-service platforms (like Ngrok) by attackers to host C2 servers, phishing sites, data exfiltration channels, and malware distribution; it documents example C2 URLs and that njRAT and Nanocore RAT comprise the vast majority of observed Ngrok-hosted C2s (Oct 2023–Apr 2024), describes responsible disclosure to Ngrok, and lists defensive controls and mitigations (network monitoring, EDR, whitelisting, access controls, audits, and intelligence sharing).