Log into SSH and run the following commands:
cd /
wget http://configserver.com/free/csf.tgz
tar -zxvf csf.tgz
yum -y install nano
nano /etc/csf/csf.conf
#Change the line that says TESTING = "1" to TESTING = "0"
#If your SSH port is anything other than 22, please add it to the TCP_IN = Line
#Hit CTRL + X, Press Y, Press Enter
service csf restart
CSF is now installed and running!