IAM Policy Changes

Identity and access management policies define the criteria for a variety of categories related to account management. With the proper rules in place, users should be able to access the minimum level of access needed for resources, also known as the principle of least privilege. Changes to the IAM policies have the potential to be malicious, where an attacker would change or delete rules to roam around an account and remain undetected. Maintaining an efficient policy can prevent this from happening. In the occurrence of an unwarranted change, it's important to review the IAM settings to make sure only the correct rule-sets are built.

https://aws.amazon.com/iam/