← Back to context

Comment by kabakabakaba

14 hours ago

Author here :)

TLDR: on Oct 2, 333 exits (~10% of Tor exits) started redirecting port 22 to 12 interception servers running a paramiko-based MITM that stole passwords and tried to drop Ebury on the target.

Thankyou for taking the time to detect and validate/verify those hosts. Is there a way you could make an outbound connection from them (maybe curl) to a site like ifconfig.me [1] and start logging which providers they are on then post a report of them on HN?

[1] - https://ifconfig.me/

  • In my scan on October 2, 26 of the 27 compromised servers outside the Quetzalcoatl relay family (most hosting multiple exits) were at FranTech/BuyVM.

    It's been discussed on the mailing list: https://lists.torproject.org/mailman3/hyperkitty/list/tor-re...

    That doesnt prove FranTech itself was compromised, but its a strong cluster. AFAIK nobody has contacted them yet, if no one does, I plan to give them a heads up in the coming days.

    • That is useful information. Historically I have blocked BuyVM on my nodes due to their pro-privacy pro-tor-exit policy. Now I just put anyone arriving from them into a moderator review queue for my silly hobby sites.

      It's a good policy to permit Tor exit nodes but it means their network will egress some of the most untoward behavior so that is expected and I would not default to assuming they are compromised, rather have some of the highest concentration of Tor exit nodes. There are pros and cons to such providers and you found one of them.

What I don't get: Why would you want to access hosts via ssh over TOR?

  • The Ebury botnet that's been around for a decade now is likely spying on Tor exit ssh tunnels looking for other criminals logging into their h4xxr jump boxes, ransomware deployments they can intercept and exploit themselves, financial crime market operators, crypto drug dealers etc.

  • - Default route is over tor and you didn't make an exception for ssh.

    - Hide where you are in the world from your employer, who owns the server. (On vacation?)

    - You're hacking the server.

    • And 4) you're the owner of the server, which is paid in bitcoin and hosted at a "bulletproof provider", and you want to leave no trace back to your "real" IP address should the authorities ever manage to seize it. Often the case for piracy, drug marketplaces and CSAM.

  • > Why would you want to access hosts via ssh over TOR?

    When you're behind a restrictive firewall which blocks anything other than HTTP/HTTPS (like at an Internet café), or when there's some upstream routing issue making reaching the server directly impossible from your location (these can be a pain to diagnose).

    Or perhaps it's simply your default: you proxy everything through Tor, and need a reason to not go through it.

    • Are there restrictive firewalls which block unknown HTTP/HTTPS but not Tor? I'd expect Tor to be blocked first.

      (And then proxying via your home is much faster and safer. You can do websocket-based proxy, but even exposing ssh server on port 443 works in a lot of places!)

  • Remote admin some shady server you control and do not want LE seeing a direct inbound ssh from you in Upper Sandusky, Ohio.

  • How does this use case differ?

    People ssh over Tor for the same reason they use Tor for any network activity: To make confidential 1) your identity to the remote host and 2) your activities to your network providers (including your ISP/workplace/etc.).

    If you want only confidential content, ssh is sufficient and so is https for web browsing. If you want the other things, you must use Tor or maybe something similar.

    • I can't really see legal use cases for (1) and (2) might get you fired if the second. 2a is a 'maybe'.

  • If the SSH host is a backdoor you installed in a company you hacked, you don't want the FBI tracing it back to you.