I'm getting too old for this shit...
Why the hell would a *voice mail message* include an *email attachment*? I figure the blending of VM & email must be a SmartPhone thing that you young whippersnappers have dreamed up in a drug-fogged brain-fart of epic proportions in the demented belief that it was hip & cool.
A voice mail message is just that, an audio recording of a person's voice. It does not & should not include anything else, otherwise it is no longer something one person leaves for another, it becomes a form of MMS/SMS akin to a video message clip, text message with animated emoji, or other idiocy that only a "Gen Z'er" would think is useful/appropriate/cool. (Am I the only one that hears "Gen Z" & thinks "Zombies!"?)
If there's an email attachment, then it's email not voice mail. If it has an address that immitates a valid sender in your contacts list, move it to the junk folder (if not already there) & warn your network security folks about it. If it has an attachment, especially if it's an HTML document, don't open it in your browser, use Notepad, Notepad++, or some other non-internet-connected text editor instead. View the source, ignore all the crap code, & focus on the content. If the server of said content is not inside the corporate network, don't visit that site. If there's JS embedded, don't enable it. If the content of the HTML file is just a "click here to read this" style command, don't click the link, forward it to your security folks, & save yourself a megaton of headache.
*Wanders off muttering about the youf of today antheir newfangled doohickies*