I have recently been combating an SMTP AUTH attack in which one of my email accounts had been compromised and was being used to solicit spam. I have been able to identify the account and change the password however I would like to further restrict my exchange server. By default exchange 2010 allows for any authenticated user to specify any email address as the MAIL FROM address and it will accept it. Is there any way to restrict this so that only the authenticated account's email address will be able to be used as the MAIL FROM address? I have been looking through all ADPermissions for the SMTP connector however I can't find any documentation on how to accomplish this. Any suggestions would be greatly appreciated.
Telnet Test Picture
SMTP Connector Properties Pictures