The detection rule titled 'O365 New Forwarding Mailflow Rule Created' identifies suspicious activities related to the creation of new mail flow rules within Office 365. Specifically, it focuses on identifying rules that might redirect or copy emails to unauthorized or external email addresses. The rule utilizes Office 365 Management Activity logs, searching for operations related to the 'New-TransportRule' and capturing specific parameters like 'BlindCopyTo', 'CopyTo', and 'RedirectMessageTo', which are associated with redirection of messages. The creation of such rules can potentially indicate attempts at data exfiltration, unauthorized access to sensitive information, or other malicious intents. The analytics provided alert security teams to scrutinize the actions of users who create these forwarding rules, thereby mitigating the risk of data breaches and ensuring the organization's information remains secure.