Hey! Let's talk about #SSH and #security!

If you've ever looked at SSH server logs you know what I'm about to say: Any SSH server connected to the public Internet is getting bombarded by constant attempts to log in. Not just a few of them. A *lot* of them. Sometimes even dozens per second. And this problem is not going away; it is, in fact, getting worse. And attackers' behavior is changing.

The graph attached to this post shows the number of attempted SSH logins per day to one of @cloudlab s clusters over a four-year period. It peaks at about 3.4 million login attempts per day.

This is part of a study we did on our production system, using logs of more than 640 million login attempts, covering more than 1,500 hosts on our side and observing more than 840 thousand incoming IP addresses.

A paper presenting our analysis and a new, highly effective means to block SSH brute force attacks ("Where The Wild Things Are: Brute-Force SSH Attacks In The Wild And How To Stop Them") will be presented next week at #NSDI24 by @sachindhke . The full paper is at https://www.flux.utah.edu/paper/singh-nsdi24

Let's dive in. 🧵