Brute.Fail: Watch brute force attacks fail in real time
So funny story, for a while I worked on a 'reverse' exploit. Which is to say morphing the response from ssh to the client with large malformed packets. The idea was to crash the client making the request. In my case I found these attacks would have like 6 to 10 attempts from the same source address. By time stamping the requests, I could evaluate if the next attack from the same address came more quickly or more slowly. I then had my server "morph" the return payload somewhat randomly and keep the three responses that caused the most slowdown. When I got to 100 variants that had "won" this selection criteria I took the three best and started over from there. After a couple of months of this I finally got a response where after one request I would not get a second.I felt extremely pleased with myself for about another month, and then my server address got hit with a massive DDOS attack (for me anyway) over my 6MBPS DSL line. So clearly I had hit a nerve somewhere :-). Anyway, I moved my server to a different address and used fail2ban to just note source IPs and put them into the IP tables as banned addresses. That works great and hasn't resulted in the same sort of drama as last time.