The AWS IAM Deactivation of MFA Device detection rule identifies when a multi-factor authentication (MFA) device associated with an AWS user account is deactivated. In the context of AWS Identity and Access Management (IAM), the deletion of an MFA device requires it to be deactivated first. This rule is critical as MFA serves as an additional security layer, preventing unauthorized access even if a user's password is compromised. The detection captures logs from AWS CloudTrail, focusing on successful operations related to deactivating or deleting MFA devices. Investigators should analyze the timestamps and determine the legitimate nature of the deactivation action, since unauthorized changes can indicate potential security breaches. The rule outlines specific steps for response and remediation, emphasizing the need to assess user permissions, initiate incident response actions, and verify compliance with security policies.