CIS Benchmark for Ubuntu 20.04 LTS: Hardening Guide

What the official CIS Benchmark covers

The CIS Ubuntu Linux 20.04 LTS Benchmark organises recommendations into the standard CIS Linux layout:

• Initial Setup
• Services
• Network
• Host Based Firewall
• Access Control
• Logging and Auditing
• System Maintenance

Recommendations are profile-tagged by Level 1 and Level 2 for Server and Workstation variants.

Key hardening areas

Mapped to real CIS Ubuntu 20.04 sections, without listing individual recommendation IDs:

Initial setup

Partitioning, package integrity, AppArmor/filesystem, and related first-boot hardening themes.

Services

Unused service reduction and SSH hardening appropriate to the selected profile.

Network & host firewall

Network kernel parameters plus host-based firewall expectations (ufw/iptables themes as in the PDF).

Access control

Accounts, sudo, PAM, and remote access themes.

Logging & maintenance

auditd/rsyslog-style auditing themes plus permission and integrity maintenance.

Why manual CIS hardening is hard at scale

• Mixed 20.04 / 22.04 / 24.04 fleets produce wrong-PDF pass rates when checklists are shared.
• Level 2 settings break workloads when applied without staging.
• Cloud-init and golden-image drift reappears after every rebuild.
• Migration programmes lose evidence discipline on “soon to be retired” 20.04 hosts that are still in production.

How CyberSilo’s CIS Benchmarking Tool helps

CyberSilo’s CIS Benchmarking Tool is built to turn “we have a PDF” into continuous configuration assessment:

• Inventory hosts by Ubuntu release and apply the matching CIS 20.04 profile.
• Score gaps across setup, services, network, access, and auditing themes.
• Detect drift after unattended-upgrades and image rebuilds.
• Keep exportable evidence through migration instead of abandoning assessment on legacy LTS hosts.

FAQ

Is there an official CIS Benchmark for Ubuntu 20.04 LTS?

Yes. CIS publishes Ubuntu Linux 20.04 LTS benchmarks with Server/Workstation L1/L2 profiles.

Should we still harden 20.04 if we are migrating?

Yes for hosts that remain in scope — assess correctly while you migrate, rather than leaving a gap.

Can we reuse the 24.04 page’s remediations?

Use them only as narrative parallels. Apply the 20.04 CIS PDF and assessment profile to 20.04 hosts.

How does CyberSilo relate to the official CIS PDF?

The official CIS Benchmark remains the authoritative recommendation source. CyberSilo automates assessment, scoring, drift detection, and remediation tracking.