[jborak]

Thanks for sharing this. I run packetriot.com, another tunneling service and I ended up writing my own scanner for endpoints using keyword lists I gathered from various infosec resources.

I had done some account filtering for origins coming out of Tor, VPN networks, data centers, etc. but I recently dropped those and added an portal page for free accounts, similar to what ngrok does.

It was very effective at preventing abuse. I also added mechanism for reporting abuse on the safety page that's presented.

[patricklorio]

Have you found a way to detect xworm c2c servers?

[jborak]

Our services were used for C2 as well. I investigated it a bit but eventually decided to just drop TCP forwarding from our free-tier and that reduced our abuse/malware reports for C2 over TCP to zero essentially.

One path I looked at was to use the VirusTotal API to help identify C2's that other security organizations were identifying and leverage that to automatically take down malicious TCP endpoints. I wrote some POCs but did not deploy them. It's something I plan on taking up again at some point next year.