cis-ubuntu2004-v300-4-3-1

Imported from nadamohamed14796-byte/cyber-strike (.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/cis-ubuntu-linux-20-04-lts-benchmark-v3/cis-ubuntu2004-v300-4-3-1/SKILL.md). Install upstream with npx skills add nadamohamed14796-byte/cyber-strike --skill cis-ubuntu2004-v300-4-3-1. Copyright stays with the author.

CIS Ubuntu Linux 20.04 LTS Benchmark v3.0.0 - Control 4.3.1

Profile

• Level: Level 1 - Server, Level 1 - Workstation
• Assessment Status: Automated

Description

nftables provides a new in-kernel packet classification framework that is based on a network-specific Virtual Machine (VM) and a new nft userspace command line tool. nftables reuses the existing Netfilter subsystems such as the existing hook infrastructure, the connection tracking system, NAT, userspace queuing and logging subsystem.

Notes:

• nftables is available in Linux kernel 3.13 and newer
• Only one firewall utility should be installed and configured
• Changing firewall settings while connected over the network can result in being locked out of the system

Rationale

nftables is a subsystem of the Linux kernel that can protect against threats originating from within a corporate network to include malicious mobile code and poorly configured software on a host.

Audit Procedure

Command Line

Run the following command to verify that nftables is installed:

dpkg-query -s nftables &>/dev/null && echo "nftables is installed"

Expected Result

nftables is installed

Remediation

Command Line

Run the following command to install nftables:

apt install nftables

Default Value

Not applicable.

References

1. NIST SP 800-53 Rev. 5: CA-9

CIS Controls

v8 - 4.4 Implement and Manage a Firewall on Servers v8 - 4.5 Implement and Manage a Firewall on End-User Devices v7 - 9.4 Apply Host-based Firewalls or Port Filtering

MITRE ATT&CK Mappings: T1562, T1562.004 | TA0011 | M1031, M1037