How can defenders detect and prevent an attacker from maintaining persistent access to user email boxes?

Defenders should regularly audit inbox rules (Get-InboxRule) and folder permissions (Get-MailboxFolderPermission) for each mailbox. After a password change, administrators should also reset any forwarding rules or delegate permissions that may have been set by the attacker. Additionally, monitoring for unusual SOAP/EWS activity, such as excessive UpdateInboxRules or AddDelegate calls, can indicate compromise. The article emphasizes that changing the password alone does not revoke previously granted permissions or rules. For comprehensive defense strategies, refer to the full Penetration Basics - Methods to Continuously Obtain Exchange User Inbox Emails article.