Technology

Yes, it’s actually a very creative name. It’s caused by the character * allowing anyone to log into an open SSH port. So it’s an amalgam of {*}{SSH}{port (hole)}.

The long story short is that if you don’t have a password set for an account, Alpine saves the user’s password hash as “*” because no password hash will ever match it. Should be safe, right? Any password will always automatically fail, because the hash algorithm cannot return “*” as a result. So the only way to log in as that user is via something besides a password.

And when musl (the underlying system that Alpine uses for SSH) gets a Null response from its password hash, it uses “*” to represent that null value. Because lots of programs throw a fit if they get a true null value. So instead of returning a null value, it just returns a *. Which shouldn’t match anything, right?

So an attacker forces the password hash to return a null value. Simple to do, because the password hash is capped at 256 characters. So just enter something with more than 256 characters. Musl takes that null value, turns it into a *, and passes that onto Alpine. Alpine takes this *, and compares it with the list of saved usernames and password hashes. And it finds that the user (who has no password set, and shouldn’t be allowed to log in with a password) has a password hash of “*”. This matches the result musl just provided, so the attacker is able to log into the system.

* ssh olé!

which you should have been doing anyway for anything exposed to the internet

i mean assholes are muscle holes.

Fail2ban with increasing jail time for repeat offenders usually takes care of the worst of it after a day or two

Did it help you find hot milfs within a mile of your location?

Among other things, change the default ssh port to something way higher.

yeah, while reading this i was going "What maniac exposes SSH to WAN anyway...?" the whole time. I fail to see any reason or point that can be justified exposing SSH to WAN.

How do you know this? What tool or utility tells you this fact? I have a port exposed for a game server but realising I don't know how many attempts are being made.

nah, find and fix as many as possible.

The person who discovered *sshole said OpenWRT is affected, but by default, that OS uses the Dropbear package, not OpenSSH, for SSH connections (though maintainers provide instructions for installing the latter).