If you've never dealt with a problem like this, you may not be ready. So, here's the most important thing you need to understand:
If you have a vulnerable application anywhere, on any port it will be found and compromised. This is a spray-and-pray vulnerability. It costs attackers nothing to try, attempts don't crash servers, and so people will try everywhere.
If you lose an application in your data center / hosting environment, that's the ballgame. It doesn't matter that the app you lost was the testing instance of a status dashboard with no real data in it, because the exploit coughs up shell access on that server. If there is one thing every black-hat attacker in the world is truly gifted at, it is pivoting from shell access on one server to shell access on every goddam server.
Please make sure you didn't just patch the app servers you know/care about. THEY ALL NEED TO BE PATCHED OR RETIRED.
Additionally:
* If you are one of those "same password on a whole bunch of services people", now is a good time to make sure nothing you care about has that password. Some app somewhere is about to lose that password.
* Now would not be the worst time in the world to go to your Twitter config, hit Settings -> Apps, and scrub out all the stuff you don't use.
* Now you know why you never give 3rd party web apps your Gmail password.