AWS Serverless IAM Least Privilege

1. Introduction

The principle of Least Privilege in Identity and Access Management (IAM) is a security concept that grants users and applications the minimum permissions necessary to perform their functions. In AWS Serverless architecture, applying the principle of least privilege is essential to minimize the potential attack surface and ensure secure operations.

2. Key Concepts

• **IAM Roles:** Temporary credentials that can be assigned to AWS services.
• **Policies:** Documents that define permissions for actions on AWS resources.
• **Resource-Based Policies:** Policies attached directly to AWS resources.
• **Trust Relationships:** Define which entities can assume a role.

3. Implementation Steps

1. **Identify Resources and Actions**: Determine the AWS resources your serverless application will interact with and the actions it must perform.
2. **Create IAM Roles**: Create roles with specific permissions tailored to your application’s needs.

   
                       aws iam create-role --role-name MyServerlessRole \
                         --assume-role-policy-document file://trust-policy.json
                       

3. **Define IAM Policies**: Write policies that grant only the permissions required.

   
                       aws iam put-role-policy --role-name MyServerlessRole \
                         --policy-name MyPolicy \
                         --policy-document file://policy.json
                       

4. **Attach Roles to Services**: Assign the created roles to your AWS Lambda functions or other services.
5. **Test and Validate**: Ensure that the permissions work as intended without excess privileges.

4. Best Practices

• Use IAM roles instead of IAM users for AWS Lambda functions.
• Regularly audit IAM policies and roles for unused permissions.
• Use AWS CloudTrail to monitor API calls and access patterns.
• Implement conditions in policies to restrict access based on specific criteria.

5. FAQ