Deny hosts is a tiny program that will add ip addresses to the /etc/hosts.deny file when automated scripts try and brute force attack the sshd port.

The main vulnerability is the ROOT account which, should never be used to log into SSHD.

Set up a new user, add a strong password and then SSH into the server, su – will then allow you root priviledges.

To setup denyhosts

yum install denyhosts

then edit the config file

nano /etc/denyhosts/denyhosts.cfg

then start the daemon

/etc/init.d/denyhosts start