What is identity and access management (IAM) in the cloud?

Identity and Access Management (IAM) in the cloud is a framework that controls who or what can access specific resources and what actions they can perform. It ensures that only authorized users, services, or systems interact with cloud infrastructure, data, or applications. IAM works by defining policies that specify permissions—such as read, write, or delete access—for resources like databases, storage buckets, or virtual machines. For example, a developer might use IAM to grant a backend service permission to write logs to a cloud storage bucket without allowing it to modify existing files. This granular control helps prevent unauthorized access and reduces security risks.

IAM systems typically include three core components: identities (users, groups, roles), policies (rules defining permissions), and resources (cloud services or data). Identities can represent human users (like developers or admins) or non-human entities (like applications or servers). Policies are often written in structured formats like JSON or YAML and attached to identities. For instance, AWS IAM uses policies like "Effect": "Allow", "Action": "s3:GetObject", "Resource": "arn:aws:s3:::example-bucket/*" to permit reading objects in a specific S3 bucket. Roles, another key concept, allow temporary permissions—like letting a virtual machine access a database without hardcoding credentials. Cloud providers like AWS, Azure, and GCP offer IAM tools with similar principles but varying syntax and features.

For developers, understanding IAM is critical for building secure applications. Misconfigured IAM policies are a common cause of data breaches, such as accidentally making a cloud storage bucket publicly readable. To avoid this, developers should follow the principle of least privilege—granting only the minimum permissions required. For example, a CI/CD pipeline might need a role to deploy code to a server but shouldn’t have permission to delete the server. Tools like AWS IAM Access Analyzer or GCP’s Policy Troubleshooter help identify overly permissive policies. Additionally, IAM integrates with other cloud services, such as audit logging (e.g., AWS CloudTrail) or multi-factor authentication (MFA), to provide layered security. By automating IAM policies through Infrastructure as Code (IaC) tools like Terraform, teams can enforce consistency and reduce human error.