Introduction

In a hybrid on-premises and AWS environment, implementing security principles like Role-Based Access Control (RBAC), Zero Trust, and Least Access is crucial to protect resources and data. This lesson will guide you through the preparation, implementation, and auditing of these principles in an environment that includes traditional Windows and Linux virtual machines, as well as AWS serverless services.

1. Role-Based Access Control (RBAC)

Overview

RBAC restricts access based on a user’s role within an organization. Access permissions are granted according to the roles defined in the system, which align with job functions.

Preparation

1. Identify Roles: List all roles in your organization.
2. Define Permissions: Map the required permissions for each role.
3. Inventory Resources: Catalog all resources and services in your hybrid environment.

Implementation

AWS IAM Roles:

• Create IAM roles with specific policies that grant necessary permissions.
• Use IAM groups to manage permissions for multiple users.

On-Premises Systems:

• Utilize Active Directory (AD) for Windows environments.
• Use LDAP or local user management systems for Linux.

Serverless Services:

• Assign specific IAM roles to AWS Lambda functions and other serverless services.

Tools

• AWS IAM: For managing roles and policies in AWS.
• Active Directory: For managing roles and permissions in Windows.
• LDAP: For managing roles in Linux.

2. Zero Trust

Overview

Zero Trust assumes that threats could be inside or outside the network, requiring verification for every access attempt.

Preparation

1. Map Data Flows: Understand how data moves through your systems.
2. Identify Assets: List all critical assets and their sensitivity levels.
3. Segment Networks: Design your network to isolate sensitive resources.

Implementation

Identity and Access Management (IAM):

• Enforce multi-factor authentication (MFA).
• Use identity providers that support federated access.

Micro-Segmentation:

• Use network segmentation techniques to isolate critical assets.
• Implement AWS Security Groups and Network ACLs for segmentation.

Continuous Monitoring:

• Deploy security monitoring tools to log and analyze access attempts.

Tools

• AWS VPC: For network segmentation in AWS.
• Security Information and Event Management (SIEM): For continuous monitoring.
• AWS Config: For auditing configuration compliance.

3. Least Access

Overview

Least Access ensures users and systems have the minimum permissions necessary to perform their functions.

Preparation

1. Assess Permissions: Review current permissions for all users and roles.
2. Define Least Privilege Policies: Create policies that enforce minimal access.

Implementation

Restrict Access:

• Implement strict IAM policies in AWS.
• Use fine-grained access control mechanisms in Linux (e.g., sudo).

Review and Revise:

• Regularly review access logs and permissions.
• Use automation tools to adjust permissions dynamically.

Tools

• IAM Policy Simulator: For testing AWS IAM policies.
• Auditd: For auditing in Linux environments.
• AWS CloudTrail: For logging and monitoring AWS API calls.

Review and Audit Plan

Preparation

1. Establish a Baseline: Document current access controls and permissions.
2. Define Audit Scope: Determine which systems and permissions to review.

Implementation

Regular Audits:

• Conduct quarterly reviews of IAM roles and policies.
• Review AD group memberships and GPOs.

Automated Tools:

• Use AWS Config Rules to continuously monitor compliance.
• Implement scripts to check and report on Linux permissions.

Remediation Policies

Immediate Action:

• Revoke unnecessary permissions discovered during audits.
• Implement MFA for any critical accounts lacking it.

Policy Adjustments:

• Update IAM policies and GPOs based on audit findings.
• Revise network segmentation and micro-segmentation strategies.

Continuous Improvement

• Training: Provide regular security training for all staff.
• Feedback Loop: Use audit results to improve security policies and practices continuously.

Conclusion

Implementing RBAC, Zero Trust, and Least Access principles in a hybrid on-premises and AWS environment requires thorough preparation, diligent implementation, and regular auditing. By following the steps outlined in this lesson, you can enhance your organization’s security posture and protect critical assets effectively.