Continuous Compliance Monitoring with AWS Config - Rule Evaluation and Auto-Remediation
Learn how to record resource configurations with AWS Config, evaluate compliance using Config rules, and set up auto-remediation actions.
Overview of Config
AWS Config is a service that continuously records configuration changes to your AWS resources and automatically evaluates compliance. It captures every configuration change, including security group modifications on EC2 instances, public access setting changes on S3 buckets, and IAM policy updates. With over 200 managed Config rules, you can define conditions such as "S3 bucket public access must be blocked" and automatically detect non-compliant resources.
Rules and Auto-Remediation
Managed rules are pre-defined rules provided by AWS, with over 200 available options including s3-bucket-public-read-prohibited, ec2-instance-no-public-ip, and iam-password-policy. Custom rules let you implement your own evaluation logic using Lambda functions. Auto-remediation executes SSM Automation documents when non-compliant resources are detected. For example, it can automatically block public access on an S3 bucket. Conformance packs bundle rule sets aligned with industry standards such as CIS AWS Foundations Benchmark and PCI DSS for batch deployment.
Conformance Packs and Aggregation
Conformance packs are templates that package multiple Config rules and remediation actions together. Pre-defined packs are available for compliance frameworks including CIS Benchmark, PCI DSS, and NIST 800-53. You can define custom conformance packs with organization-specific rule sets and deploy them across your entire Organizations structure at once. Config Aggregator consolidates compliance status from multiple accounts and regions into a single account, providing a dashboard view of organization-wide compliance. Advanced queries let you run cross-account searches such as "find all resources with unencrypted EBS volumes across all accounts." For a deeper look at Config, you can also explore related books on Amazon.
Optimizing Config Costs
Config pricing consists of the number of configuration items recorded (approximately $0.003 per item), rule evaluations (approximately $0.001 per evaluation), and conformance pack evaluations. Enabling recording for all resource types can result in a massive number of configuration items, so you should limit recording to only the resource types required for compliance to manage costs. Use a mix of periodic evaluation (every 24 hours) and change-triggered evaluation, applying periodic evaluation to resources that change infrequently. Config's advanced queries are available at no additional charge and can be leveraged for compliance reporting.
Summary
AWS Config is a service that records resource configuration changes and continuously evaluates compliance. Conformance packs let you batch-deploy rule sets for CIS Benchmark and PCI DSS, while Aggregator provides organization-wide compliance visibility. Auto-remediation automates the entire flow from detecting non-compliant resources to fixing them, maintaining continuous compliance.