alt Hacker NewsBut the firewall wouldn't have saved them if they're running a public web service or need to interact with external services.
I guess you can have the appserver fully firewalled and have another bastion host acting as an HTTP proxy, both for inbound as well as outbound connections. But it's not trivial to set up especially for the outbound scenario.
No you're right, I didn't mean the firewall would have saved them, but just as a general point of advice. And yes a second VPS running opnSense or similar makes a nice cheap proxy and then you can firewall off the main server completely. Although that wouldn't have saved them either - they'd still need to forward HTTP/S to the main box.