HTML Sanitizer is modifying emails using S/MIME

Overview

The HTML sanitizer is modifying the emails causing the email client to warn that the signed email has been manipulated on the way.

Solution

The HTML sanitizer is working as intended. In order to prevent GFI MailEssentials from modifying the email, you need to whitelist the emails in the HTML Sanitizer and also disable rule ID's 7 and 10 in Exploit List of Email Exploit Engine. The procedure is as follows:

1. Open the GFI MailEssentials Configuration UI.
2. Navigate to the Email Security > HTML Sanitizer to open its properties.
3. Select the Whitelist tab and make an entry for the address that is sending the emails.
4. Navigate to the Email Security > Email Exploit Engine > Exploit List.
5. Check off rule ID's 7 and 10, then click the Disable Selected button at the top.
6. Click OK and exit the console.

Testing

Send a test email to confirm the operation is successful.

If the issue still persists, please generate the troubleshooting logs as follows:

• Make sure that you have tracing enabled.
• Wait for at least 30 minutes to gather enough information and for the issue to be reproduced.
• Run the troubleshooter:
  1. Start > Programs > GFI MailEssentials > Troubleshooter
  2. Follow the Log Generation Wizard for collecting the required and pertinent information.
  3. Select New Case when completing the log generation to attach the logs to a new case that will be automatically created, or open a support ticket manually and attach the logs to that ticket, so that the Support team can investigate the problem.