This is just script kiddies doing their stuff. The first good thing is that you obviously check your logs, something that's essential if you're running an publically accessible service such as http. Also, at the very least, make sure your machine stays up to date with all the latest security patches.
If you want to further harden your security, use strong passwords (if you're not doing so already) and change them frequently. Turn off or disable any services that you don't need. Also consider running any machine with publically accessible services in a DMZ so if it does get hacked you minimise the damage to just one machine, not your whole lan.