Combining security controls to apply defense in depth (for example, AWS Certificate Manager [ACM], AWS WAF, AWS Config, AWS Config rules, Security Hub, GuardDuty, security groups, network ACLs, Amazon Detective, Network Firewall)

By combining various tools and practices, organizations can create a more robust and resilient security posture that can better prevent, detect, and respond to threats. In the context of AWS and the AWS Certified DevOps Engineer – Professional (DOP-C02) exam, understanding how to implement such a strategy using AWS services is essential.

Security at the Perimeter: Network ACLs and AWS WAF

At the perimeter of your network, controlling access is key to preventing unauthorized entry.

• Network ACLs (Access Control Lists) act as a firewall for associated subnets, controlling traffic at the protocol and port level. They can be configured with inbound and outbound rules to allow or deny traffic
• AWS Web Application Firewall (WAF) protects your web applications from common web exploits and bots that may affect availability, compromise security, or consume excessive resources.

Example:

By setting up a Network ACL, you can block traffic from suspicious IP addresses, while AWS WAF can be configured to stop SQL injection and cross-site scripting attacks.

Encryption with AWS Certificate Manager (ACM)

For securing data in transit, it’s critical to implement encryption using SSL/TLS certificates.

• AWS Certificate Manager (ACM) simplifies the task of managing, provisioning, and deploying public and private Secure Sockets Layer/Transport Layer Security (SSL/TLS) certificates for use with AWS services.

Example:

With ACM, you can quickly request a certificate, deploy it on AWS resources like Elastic Load Balancers, and let AWS handle the renewals.

Monitoring and Compliance: AWS Config and AWS Config Rules

Ongoing monitoring and ensuring compliance are key to maintaining a secure environment.

• AWS Config provides a detailed inventory of your AWS resources and configuration and continuously monitors and records your AWS resource configurations.
• AWS Config Rules allows you to create rules that automatically check the configuration of AWS resources recorded by AWS Config.

Example:

You might use AWS Config rules to ensure that all new Amazon S3 buckets are encrypted by default or to check whether your EC2 instances comply with your applied tagging strategy.

Threat Detection and Continuous Monitoring: GuardDuty and Security Hub

Detecting threats in real-time ensures you can respond to potential security issues swiftly.

• Amazon GuardDuty is a threat detection service that continuously monitors for malicious activity and unauthorized behavior.
• AWS Security Hub gives you a comprehensive view of your high-priority security alerts and compliance status across AWS accounts.

Example:

GuardDuty can alert you to unusual API calls or potentially unauthorized deployments, whereas Security Hub can aggregate and prioritize these findings across multiple AWS services.

Deep Analysis and Investigation: Amazon Detective

For investigating security incidents, a service that can collate and analyze data simplifies the process.

• Amazon Detective makes it easy to analyze, investigate, and quickly identify the root cause of potential security issues or suspicious activities.

Example:

After receiving an alert from GuardDuty about a potential compromise, Amazon Detective can help you analyze and visualize the extent of the impact.

Advanced Network Protection: AWS Network Firewall

For stateful firewall protection, AWS offers advanced options to secure your VPC.

• AWS Network Firewall provides customizable, stateful firewall protection for your VPCs.

Example:

AWS Network Firewall can be configured to block traffic from known malicious IP addresses, provide intrusion prevention and detection, and filter web traffic to enforce corporate compliance standards.

Security at Instance Level: Security Groups

Finally, at the instance level, security groups act as virtual firewalls for EC2 instances.

• Security Groups control inbound and outbound traffic to instances.

Example:

You can configure a security group to allow SSH access (port 22) only from your corporate IP range, significantly reducing the attack surface.

Combining Security Controls Example

Here’s how you might layer these controls within an AWS environment:

• Perimeter: Deploy Network ACLs and AWS WAF for the first line of defense against unauthorized network access and common web exploits.
• Encryption: Use ACM to handle SSL/TLS certificates for your load balancers and cloud front distributions.
• Monitoring/Compliance: Implement AWS Config with custom rules for real-time resource configuration checks.
• Continuous Monitoring/Threat Detection: Use GuardDuty for detecting unusual patterns and Security Hub to aggregate and analyze security data.
• Investigation: Leverage Amazon Detective to dig deeper after a security incident is detected.
• Network Protection: Set up AWS Network Firewall at key points within your VPC for stateful filtering.
• Instance Level: Use security groups for fine-grained access control to EC2 instances.

By implementing and combining these controls, AWS users can create a robust, multi-layered security infrastructure that aligns with the best practices of defense in depth, significantly reducing the likelihood of successful attacks.