A logistics broker's operations engineers sign in as IAM users with AdministratorAccess. After an accidental mass termination of EC2 instances, the security team requires that ec2:TerminateInstances and ec2:StopInstances succeed only when the caller signed in with MFA. Engineers must keep all their other permissions, whether or not they used MFA. Which policy change should a CloudOps engineer make for the engineers' group?
Choose one answer.
Show the answer and explanation
Answer: C
Explanation
Explicit Deny statements always win in IAM policy evaluation, so they are the way to restrict an action that a broad policy allows. aws:MultiFactorAuthPresent shows whether the caller authenticated with MFA, and BoolIfExists treats a missing key, as with long-term access keys, as not authenticated with MFA. Allow statements with conditions cannot remove permissions granted elsewhere.