I'm running a small webserver on Ubuntu 12.04.
Last night, the server topped off at 100% cpu usage and crashed. This is unusual as I'm normally around 1-5%. I suspect a DDoS attack from someone related, but I'm not certain. I searched apache logs, syslog, messages, fail2ban logs but I couldn't find anything that explains what happened.
How can I figure out the cause of the crash? How can I possibly prevent it?