Penetration Testing AWS: A Practical Cloud Security Guide

AWS is everywhere. And where there’s cloud infrastructure, there’s need for security testing. But pentesting AWS is different from traditional testing.

Important: Get Permission First

AWS requires explicit authorization before penetration testing. Submit a request through AWS vulnerability testing request form.

Find the form at: aws.amazon.com/security/penetration-testing/

Testing without approval violates AWS Terms of Service.

Key AWS Attack Surfaces

S3 Buckets

Misconfigured S3 buckets are the #1 AWS vulnerability. Check for:

• Public access when it shouldn’t be
• Missing encryption at rest
• Overly permissive bucket policies
• Exposed access keys in bucket contents

Tools: aws s3 ls, S3Scanner, bucket_finder

IAM Misconfigurations

Identity and Access Management errors lead to privilege escalation.

• Overly permissive policies like “*:*” permissions
• Users with AdministratorAccess
• Long-lived access keys
• Missing MFA on privileged accounts

Tools: ScoutSuite, Prowler, cloudsplaining

Lambda Functions

Serverless doesn’t mean secureless. Check for:

• Environment variables with secrets
• Overly permissive execution roles
• Public function URLs
• Vulnerable dependencies

EC2 Instances

Classic targets in cloud clothing. Check for:

• Exposed SSH (port 22) to the world
• SSM agent misconfigurations
• Instance metadata service (IMDSv1) exposure
• User data scripts with secrets

RDS and Databases

Database exposure is catastrophic. Check for:

• Public accessibility enabled
• Security groups allowing broad access
• Unencrypted storage
• Weak authentication

The Metadata Service Attack

AWS metadata service at 169.254.169.254 is a prime target. If an application has SSRF:

Step 1: Access metadata:

Step 2: Retrieve IAM credentials:

Step 3: Use credentials to enumerate the account

Mitigation: Enforce IMDSv2, which requires session tokens.

Tools for AWS Pentesting

• ScoutSuite: Multi-cloud security auditing
• Prowler: AWS security best practices checker
• Pacu: AWS exploitation framework
• CloudGoat: Vulnerable AWS environment for practice

Practice Environments

Use these to learn safely:

• CloudGoat – Vulnerable by design AWS environment
• Flaws.cloud – AWS security CTF challenges

Pentest Workflow

1. Submit testing request to AWS
2. Get approval confirmation
3. Enumerate account structure, regions, services
4. Test S3 buckets and storage
5. Audit IAM policies and roles
6. Check network configurations
7. Test compute instances and Lambda
8. Document findings with remediation steps

Bottom Line

AWS pentesting requires understanding cloud-specific attack surfaces: S3, IAM, metadata services.

Get authorized. Know your tools. Stay in scope.