AWS Sign-in IAM User Login Flow Username Enumeration
Published Thu, Jan 23rd, 2025
Platforms
Summary
A vulnerability in AWS IAM Sign-in login flow could allow attackers to enumerate IAM usernames by measuring server response times. This issue affected AWS Sign-in IAM User login flow prior to January 16, 2025. AWS has since introduced a delay in response times across all authentication failure scenarios to mitigate the vulnerability.
Monitor sign-in activity, including failed and successful sign-in events, using AWS CloudTrail. Refer to the CloudTrail Event Reference documentation for more information.