Hardened Ubuntu 26.04 (ARM)

This is a repackaged open source software product wherein additional charges apply for Citadel security hardening, ongoing image maintenance, release evidence, and US-based support.

Hardened Ubuntu 26.04 (ARM) gives teams a production-ready ARM64 operating system baseline for Citadel Hardened Baseline-scoped workloads on AWS.

Move from a general-purpose ubuntu-26.04 image to a documented, security-focused starting point without spending weeks designing controls, building hardening automation, troubleshooting configuration dependencies, and assembling release evidence. Citadel handles the operating system baseline so your team can focus on your applications and the controls specific to your environment.

What You Get

• Citadel-applied ubuntu-26.04 26.04 security hardening designed to support Citadel Hardened Baseline infrastructure requirements
• Security-focused configuration across authentication, account policy, privilege boundaries, audit logging, networking, services, kernel settings, file permissions, and other operating system safeguards
• Current ubuntu-26.04 package and security updates applied during the controlled image build
• Pre-hardening and post-hardening assessment results, remediation history, and a release-specific evidence report for the exact image release
• A clean, application-neutral AMI with no bundled business applications, security agents, or platform lock-in
• Ongoing Citadel image maintenance and direct access to a US-based support team

Built for Security-Focused and Regulated Workloads

Use this image as a repeatable baseline for:

• Security-focused production workloads
• Regulated development and test environments
• Audit remediation projects
• Golden image programs
• Organizations that need a faster path to a defensible Linux baseline

The AMI helps reduce manual hardening effort and configuration drift across AWS accounts and environments. Infrastructure teams can deploy the same reviewed baseline behind their own network controls, identity model, deployment pipeline, observability stack, backup policy, and workload configuration.

Security and compliance teams also gain release records that are easier to trace directly to the image being deployed.

This image is built for ARM64 EC2 instances and supports AWS Graviton instance families and ARM64-native application stacks.

Deploy and Operate with Confidence

The image is ready for use when launched. Citadel recommends AWS Systems Manager Session Manager (SSM) for administrative access whenever possible so SSH does not need to be exposed to the public Internet.

If SSH is required, use the ubuntu account, your selected EC2 key pair, and tightly scoped network access.

Detailed usage instructions in this listing cover connection methods, accessing hardening evidence, and getting support.

For routine updates, apply ubuntu-26.04 security patches through your approved change process. When Citadel publishes a new image version, validate it outside production before using a controlled replacement or migration process.

Hardening Evidence

Each Citadel release includes supporting documentation and release-specific hardening evidence. Use the Citadel documentation and Trust Center resources referenced in this listing to review:

• Applied security controls
• Pre-hardening and post-hardening assessment results
• Remediation history
• Release-specific validation evidence
• Documented exceptions, where applicable

US-Based Support Included

Email support@citadelpci.com  for help with:

• Choosing the right image
• Understanding hardening behavior
• Patching or upgrade planning
• Locating release evidence
• Troubleshooting image behavior
• Citadel Hardened Baseline review questions related to the operating system baseline

Support requests are handled by Citadel's US-based team.

Scope and Customer Responsibility

This AMI is designed to support Citadel Hardened Baseline infrastructure objectives, but launching a hardened image does not by itself make an application, AWS account, regulated environment, or organization secure or compliant with any external framework.

Customers remain responsible for the security and compliance of their complete environment, including application security, IAM, network segmentation, encryption, key and secret management, logging, monitoring, vulnerability management, backups, incident response, operational procedures, and compliance validation.

Review the provided evidence against your organization's requirements and involve your assessor where appropriate.