Is ngrok safe to use or can it be compromised?
SecurityNgrokSecurity Problem Overview
Is ngrok a safe tool to use? I was reading a tutorial which recommended to use ngrok test API responses that I make to outside services that need to connect to my endpoints also.
Security Solutions
Solution 1 - Security
There is no source code available for Version 2.0, considering it started as an open source project in 2014. I am suspect of any code that opens a tunnel to my localhost from the cloud. Pretty scary stuff especially without source code!
Solution 2 - Security
I found good rating, but vacuous information here:
http://www.scamadviser.com/is-ngrok.com-a-fake-site.html
The kicker for me is
https://developer.atlassian.com/blog/2015/05/secure-localhost-tunnels-with-ngrok/
where the Atlassian folks recommend it highly.
I think I am going to use it.
Solution 3 - Security
It opens up a tunnel to your dev machine, which is partially secured by obscurity (a hard to guess subdomain), and can be further secured by requiring a password. But you're still opening yourself up to ngrok itself, and the company is completely opaque (no address, no employees, no business name, no LinkedIn presence; all I can find is that it has 1-10 employees and is private; not even sure what country its based in). On top of that the code is not open-sourced. No reason to think they're not legit, but not a lot of information available to build trust.
You may be able to use ngrok and other local tunnel services with more security by encrypting the traffic. See https://security.stackexchange.com/questions/177280/end-to-end-encryption-for-localtunnel-ngrok-setup/177357#177357 for more information.
Solution 4 - Security
If anyone is concerning compromising their development environment, you can use Docker. There are many ngrok/docker projects but here is the one I chose: https://github.com/gtriggiano/ngrok-tunnel
for macOS, use "TARGET_HOST=docker.for.mac.localhost"
Solution 5 - Security
They now offer a service where you locally run only ssh, no need to run any of their code on your machine.
You run something like ssh -R 80:localhost:8501 tunnel.us.ngrok.com http. This connects to one of their hosts and forwards connections they receive back to your machine and the service you run on localhost:8501.
This seems secure to me, the only thing is that you don't know what information they collect and who is connecting to your exposed service. They print all connections, but it's their binary that does this and someone might well listen in without you noticing. You can check connections on your end, but you cannot be sure who it is that connects.