Automating IAM Cleanup: How I Built an Inactive Users Detection System on AWS Using Lambda, Terraform & SNS

Step 2 — Writing the Lambda Function (Python)

The core logic was written in Python using boto3. It:

• Lists all IAM users




• Checks PasswordLastUsed




• Flags users inactive for over 90 days




• Saves the list in S3




• Sends it as an email notification via SNS

Step 4 — Notifications and Output

• A file containing the list of inactive users is automatically uploaded to S3




• An email alert is sent with the same content via SNS

Here’s the !