The 'Logins Without MFA' rule is designed to identify any AWS console logins that occur without the use of Multi-Factor Authentication (MFA). It leverages AWS CloudTrail logs to track login events, checking specifically for the absence of MFA in successful console logins. This rule is essential for compliance purposes as it helps ensure that only secure logins are allowed, thereby promoting better security practices within the AWS environment. High severity indicates potential risks, prompting immediate remediation steps to enforce MFA usage, which is a critical security measure for protecting accounts against unauthorized access. The rule includes various test cases, some of which validate successful logins both for IAM users and root users while explicitly checking for the MFA status in those logins. It also covers scenarios such as failed logins and logins initiated through identity provider systems, providing a comprehensive detection mechanism for policy violations regarding MFA usage.