Only Allow Authorized Network Services in SuSEfirewall2

Description

The SuSEfirewall2 package can be installed with the following command:

$ sudo zypper install SuSEfirewall2

The SuSEfirewall2 service can be enabled with the following command:

$ sudo systemctl enable SuSEfirewall2.service

Check the firewall configuration for any unnecessary or prohibited functions, ports, protocols, and/or services by running the following command:

# grep ^FW_ /etc/sysconfig/SuSEfirewall2
FW_SERVICES_ACCEPT_EXT="0/0,tcp,22,,hitcount=3,blockseconds=60,recentname=ssh"

Ask the System Administrator for the site or program PPSM Component Local Services Assessment (Component Local Services Assessment (CLSA). Verify the services allowed by the firewall match the PPSM CLSA.

Rationale

To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. SUSE operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the SUSE operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or address authorized quality-of-life issues.