CIS Compliance Made Easy: Automating Ubuntu AMI Hardening with EC2 Image Builder
AWS EC2 Image Builder to automatically build hardened Amazon Machine Images (AMIs), and combining it with Ubuntu Security Guide (USG)
1. Problem Statement
In regulated industries such as healthcare, finance, government, and defense, infrastructure and systems must adhere to strict compliance standards. One of the most commonly accepted benchmarks for system hardening is the CIS (Center for Internet Security) Level 1 baseline, which outlines security configurations that must be applied to operating systems and applications to reduce vulnerability exposure.
Many organizations using Ubuntu on AWS EC2 lack a streamlined and automated way to create secure, compliant AMIs (Amazon Machine Images) that conform to CIS Level 1 standards. While AWS provides EC2 Image Builder for creating custom AMIs, it does not natively include CIS compliance tools or automated hardening workflows. Ubuntu provides a tool called USG (Ubuntu Security Guide) that can apply CIS hardening policies, but integrating USG into an automated pipeline requires multiple steps, subscription registration, manual configuration, and thorough cleanup.
Additionally, without proper sequencing of installation, hardening, and cleanup steps, the resulting AMIs may be incomplete, improperly secured, or non-functional. Manual setup also increases human error risk, leads to inconsistent images, and lacks traceability and repeatability.
To resolve these issues, we need an automated, repeatable pipeline using AWS EC2 Image Builder that:
Installs and activates Ubuntu's USG tool via a valid Ubuntu Pro subscription.
Applies the CIS Level 1 server profile using
usg fix.Cleans up machine-specific metadata (like machine IDs and logs) to ensure AMIs are generic and reusable.
Allows for customization, testing, versioning, and reporting.
This automation must also support compatibility with Ubuntu 24.04 LTS and be flexible enough for future reuse, scheduling, and scaling. The solution should help DevOps, CloudOps, and SecOps teams meet compliance goals with minimal manual intervention while ensuring each AMI build remains consistent, secure, and audit-ready.
2. Why We Need This Use Case
In today's cloud environments, ensuring that virtual machine images are compliant with security benchmarks is crucial. The Center for Internet Security (CIS) provides industry-recognized guidelines that help secure systems against vulnerabilities.
By using AWS EC2 Image Builder to automatically build hardened Amazon Machine Images (AMIs), and combining it with Ubuntu Security Guide (USG) tools, you can ensure that your Ubuntu AMIs are:
Secure-by-default
Regularly updated
CIS-compliant
Repeatable across environments
This automation eliminates manual hardening processes and reduces misconfiguration risks while ensuring compliance for every new machine that’s spun up.
3. When We Need This Use Case
You need this use case when:
Compliance is mandatory, such as for ISO, HIPAA, SOC2, or other regulatory frameworks.
You want to deploy secure Ubuntu VMs at scale across dev, staging, and production environments.
Teams want to standardize security across all AMIs using automated pipelines.
Manual OS hardening is becoming error-prone, repetitive, and hard to audit.
You're building an immutable infrastructure where pre-configured AMIs reduce configuration drift.