What would be the MOST efficient way to achieve these goals?
Use Amazon Inspector to determine which systems do not have the latest patches applied, and after 30 days, redeploy those instances with the latest AMI version.
Configure Amazon EC2 Systems Manager to report on instance patch compliance, and enforce updates during the defined maintenance windows.
Examine AWS CloudTrail logs to determine whether any instances have not restarted in the last 30 days, and redeploy those instances.
Update the AMIs with the latest approved patches, and redeploy each instance during the defined maintenance window.
Explanations:
While Amazon Inspector can identify vulnerabilities and missing patches, it does not directly enforce compliance or automate the application of patches. Redeploying instances with the latest AMI after 30 days does not specifically address the requirement to ensure updates are applied within that timeframe.
Amazon EC2 Systems Manager is designed to manage and automate tasks such as patch compliance reporting and enforcement. By using Systems Manager, the Security Engineer can effectively monitor instances for compliance with patch levels and apply necessary updates during defined maintenance windows, thus ensuring no system exceeds 30 days without approved updates.
Examining AWS CloudTrail logs for restart events does not directly relate to patch compliance. CloudTrail logs record API calls and events but do not provide information on the patch status of instances. Additionally, simply redeploying instances based on restart information does not guarantee that patches are applied within the specified timeframe.
While updating AMIs with the latest approved patches is a good practice, simply redeploying each instance during a maintenance window does not ensure that all instances are consistently monitored for compliance or that they receive timely updates. This option lacks a mechanism for ongoing compliance verification, which is critical to the engineer’s goals.