Masking attachments

Masking an attachment renames attachments with the specified extensions. The renaming replaces the last character of the extension with an underscore ‘_’. For example, if you mask “EML” attachments, a file named “test_email.eml” is renamed “test_email.em_”.

This stops the attachment being automatically associated with its appropriate executable in Windows and therefore avoids dangerous actions being triggered automatically.

We recommend that you mask “EML” attachments, because these can cause email clients such as Outlook and Outlook Express to execute code automatically.

Click the link on Mask attachments with these extensions to specify which attachments to mask.

Inverting the mask action

You can invert masking by extension. This enables you to specify that all extensions except those specified are subject to the Mask action. If you want to do this, select the radio button Mask all extensions except these.