This feature is an Exim feature available trough the Exim Configuration Manager in WHM. It allows you to filter well-known dangerous attachments files – as exe, reg, scr etc. extensions.
When a server will receive an email containing a blocked attachment, it will generate an error message:
This message was created automatically by mail delivery software.EXIM error message
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
This message has been rejected because it has
a potentially executable attachment “sss.exe”
This form of attachment has been used by
recent viruses or other malware.
If you meant to send this file then please
package it up as a zip file and resend it.
Steps to block dangerous email attachments in cPanel/WHM:
1. Login to your WHM root account
2. Navigate to Service Configuration >> Exim Configuration Manager
3. In the Basic Editor look for the Filters tab
4. Enable the option Attachments: Filter messages with dangerous attachments