Web Shield - Web scanning
Manage these settings at: Menu ▸ Settings (gear icon) ▸ Active Protection ▸ Web Shield ▸ Customize ▸ Web scanning
The Web Shield protects you from harmful content on the Internet. Here you can specify what kind of content is scanned.
To activate this feature, check the box Enable web scanning in the Main settings tab for the Web Shield.
You can specify that all files are scanned, or just those with particular extensions and MIME types.
Finally, you can also select whether or not to unpack compressed files which have valid digital signatures. By default, those files with valid signatures are not unpacked because they are from trusted sources.