Vulnerability Discussion

Firewalls protect computers from network attacks by blocking or limiting access to open network ports. Application firewalls limit which applications are allowed to communicate over the network.

Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232

Check

Verify the operating system enabled an application firewall.

Check to see if "firewalld" is installed with the following command:

# yum list installed firewalld
firewalld-0.3.9-11.el7.noarch.rpm

If the "firewalld" package is not installed, ask the System Administrator if another firewall application (such as iptables) is installed.

If an application firewall is not installed, this is a finding.

Check to see if the firewall is loaded and active with the following command:

# systemctl status firewalld
firewalld.service - firewalld - dynamic firewall daemon

Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)
Active: active (running) since Tue 2014-06-17 11:14:49 CEST; 5 days ago

If "firewalld" does not show a status of "loaded" and "active", this is a finding.

Check the state of the firewall:

# firewall-cmd --state
running

If "firewalld" does not show a state of "running", this is a finding.

Fix

Ensure the operating system's application firewall is enabled.

Install the "firewalld" package, if it is not on the system, with the following command:

# yum install firewalld

Start the firewall via "systemctl" with the following command:

# systemctl start firewalld