CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 - Control 3.4.2.2
Description
Uncomplicated Firewall (ufw) is a frontend for iptables. ufw provides a framework for managing netfilter, as well as a command-line interface for manipulating the firewall.
Rationale
Running both the nftables service and ufw may lead to conflict.
Impact
None.
Audit Procedure
Command Line
Run the following command to verify that ufw is either not installed or disabled. Only one of the following needs to pass:
Run the following command to verify that ufw is not installed:
dpkg-query -s ufw &>/dev/null && echo "ufw is installed"
Nothing should be returned.
Run the following command to verify ufw is disabled:
ufw status
Expected output: Status: inactive
Run the following command to verify that the ufw service is masked:
systemctl is-enabled ufw
Expected output: masked
Expected Result
ufw is not installed, or Status: inactive and masked.
Remediation
Command Line
Run one of the following commands to either remove ufw or stop and mask ufw:
Run the following command to remove ufw:
apt purge ufw
-OR-
Run the following commands to disable ufw:
ufw disable
systemctl stop ufw
systemctl mask ufw
Default Value
ufw is installed and enabled by default.
References
- NIST SP 800-53 Rev. 5: CA-9, SC-7
- CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0
CIS Controls
Version 8
4.4 Implement and Manage a Firewall on Servers - Implement and manage a firewall on servers, where supported.
4.5 Implement and Manage a Firewall on End-User Devices - Implement and manage a host-based firewall or port-filtering tool on end-user devices.
Version 7
9.4 Apply Host-based Firewalls or Port Filtering - Apply host-based firewalls or port filtering tools on end systems, with a default-deny rule that drops all traffic except those services and ports that are explicitly allowed.
Profile Applicability
- Level 1 - Server
- Level 1 - Workstation
Assessment Status
Automated
