AWS IAM, short for Amazon Web Services Identity and Access Management, is the policy engine that decides what users, roles, and access keys can do inside AWS. It uses permissions, policies, and conditions to control access to services, APIs, and resources. In practice, IAM is the gatekeeper for cloud actions such as starting instances, reading storage, or invoking managed AI services.
In cyber security, IAM matters because a stolen credential does not need an exploit chain if it already belongs to a powerful identity. Attackers often reuse leaked access keys or compromised roles to perform legitimate-looking API calls, generate costs, or change security settings. Defenders reduce this risk with least privilege, temporary credentials, MFA for human users, key rotation, and logging in services such as CloudTrail. Monitoring unusual permissions, API usage, and model invocations can reveal abuse before it becomes a major billing or data incident.