The Unexpected Attachment
Scammers access one of your associates’ email accounts or social networks and send out fake emails or direct messages to all of his or her contacts. They often include an attachment or a link to a fraudulent file-sharing website and ask you to download a file from there. If you download the files, they spread destructive malware on your computer, locking down all of the legitimate files on your device and holding it for ransom.
If you receive an unexpected attachment or link to a file-sharing website from a contact, do not open it! Contact the person directly—preferably via another channel than how you received it, in case they have been hacked—and confirm they sent you an attachment.