Only Allow Authorized Network Services in ufw

Description

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

$ sudo ufw show raw
Chain OUTPUT (policy ACCEPT)
target prot opt sources destination
Chain INPUT (policy ACCEPT 1 packets, 40 bytes)
pkts bytes target prot opt in out source destination
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination

Ask the System Administrator for the site or program PPSM 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. 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 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 to address authorized quality of life issues.