AWS Identity and Access Management (IAM)
AWS Identity and Access Management (IAM) is a web service that helps you securely control access to AWS resources. IAM enables you to manage users and their level of access to the AWS Console and AWS resources, implementing the principle of least privilege across your AWS environment.
Core Components​
IAM Users: Individual identities with unique security credentials for people or applications that need to interact with AWS services.
IAM Groups: Collections of users that make it easier to specify and manage permissions for multiple users.
IAM Roles: Identities with permissions that can be assumed by users, applications, or services for temporary access.
IAM Policies: JSON documents that define permissions and specify what actions are allowed or denied on which resources.
How IAM Works​
IAM operates on a default-deny basis, meaning all actions are prohibited unless explicitly allowed. When a request is made to AWS, IAM evaluates the applicable policies to determine whether to allow or deny the request. This evaluation considers the user's identity, the resource being accessed, and the action being performed.
Use Cases​
Workforce Access Management​
Create individual IAM users for employees, contractors, and partners who need access to AWS resources, ensuring each person has their own credentials and appropriate permissions for their role.
Application Authentication​
Use IAM roles to provide applications running on EC2 instances, Lambda functions, or other AWS services with the permissions they need to access other AWS resources securely.
Cross-Account Access​
Enable secure access between different AWS accounts using cross-account roles, allowing organizations to maintain separate accounts while enabling controlled resource sharing.
Temporary Access​
Provide temporary, elevated permissions to users or applications using IAM roles with time-limited access, perfect for maintenance tasks or emergency access scenarios.
Connection to Other AWS Services​
Amazon EC2: Attach IAM roles to EC2 instances to provide applications with secure access to other AWS services without embedding credentials in code.
AWS Lambda: Lambda functions can assume IAM roles to access other AWS services, enabling serverless applications to interact securely with resources like S3 or DynamoDB.
Amazon S3: Use IAM policies to control who can access specific S3 buckets and objects, with granular permissions for different types of operations.
Amazon RDS: Control access to database instances and snapshots using IAM database authentication, eliminating the need for database passwords.
AWS CloudTrail: IAM integrates with CloudTrail to provide detailed logging of all API calls and access attempts for security auditing and compliance.
AWS Organizations: IAM works with Organizations to provide centralized management of permissions across multiple AWS accounts.
Key Features​
Multi-Factor Authentication (MFA): Add an extra layer of security by requiring users to provide a second form of authentication in addition to their password.
Access Analyzer: Continuously monitors and analyzes resource-based policies to help identify unintended access to your resources.
Policy Simulator: Test and validate IAM policies before deploying them to ensure they work as expected without risking security.
Credential Reports: Generate reports showing the status of all users and credentials in your account for security auditing.
Benefits​
Fine-Grained Control: Define precise permissions for specific resources and actions, ensuring users have exactly the access they need.
Centralized Management: Manage all user access and permissions from a single location, simplifying administration and improving security.
Integration: Works seamlessly with all AWS services, providing consistent access control across your entire AWS infrastructure.
No Additional Charges: IAM is provided at no additional charge, making it cost-effective to implement comprehensive access control.
AWS IAM provides the foundation for secure access management in AWS, enabling organizations to implement robust security practices while maintaining the flexibility needed for diverse access requirements and use cases.