Vulnerability Assessment of a EAL 4 system

I am looking at a Linux server which has been
accredited as a EAL4 system by IBM.  During the
assessment, I was looking for standard Linux
protections like iptables, ssh etc.  On this server,
there is no iptables.

Regardless, I would like to know how to evaluate a EAL
4 system.  What do you need to look for in the EAL 4
system in production that could become vulnerable?

Thank you in advance for any help.