This is a local privilege escalation vulnerability. The attacker has to have an account on the *nix machine and be able to log on as an ordinary user, in order to try to become root.
This is very different from attacks over the internet. While a user could log in remotely with SSH, he still needs an local ID and password to connect.
So are they saying only local access as root can make this happen?
I’m gonna pass this on to my peeps on the job. But there are tons of ways of killing your linux server as root. Doesn’t require and exploit; just bad command line statements.
That's assuming the local user has a decent password. But even if they do...
Suppose the local user takes his laptop on a trip. It has a private SSH key for login, and the key has a null or trivial passphrase for convenience (sadly, very common).
Thief lifts the laptop from the hotel room, transfers the hard drive to a USB enclosure, plugs it into their own laptop, and checks /home or C:\Users or C:\cygwin\home.
Half an hour max; they're in. Meanwhile the local user hasn't even come back from dinner. By the time they realize it's missing, reach somebody in IT on the phone, and disable the account, the thief is long since done.
2-factor authentication is a wonderful thing.