The detection rule titled 'O365 Bypass MFA via Trusted IP' is designed to monitor and identify instances where new IP addresses are added to the 'trusted IPs' list within an Office 365 environment. The rule leverages O365 audit logs, particularly events related to the modification of trusted IP settings. This capability is crucial because permitting additional IPs within the trusted list can facilitate bypassing Multi-Factor Authentication (MFA), a fundamental security measure. Such activity is potentially indicative of a security compromise, allowing unauthorized access to sensitive systems or data. The rule executes a search within the O365 management activity logs for the operation 'Set Company Information.' It looks for changes in the 'StrongAuthenticationPolicy' field, captures any newly added IP addresses, and compares these against the previous trusted IPs. Any new additions that don't have an existing corresponding entry in the old values are flagged for further investigation. Given the significance of MFA in protecting user accounts, any modifications to the trusted IPs warrant immediate scrutiny to ascertain the legitimacy of the actions taken. The rule aims to enhance security posture against potential attacks targeting MFA mechanisms.