Vishing, short for 'voice phishing' is the fradulent practice of making phone calls or leaving voice messages pretending to be from legitimate companies or organizations intended to get people to reveal personal information.

Vishing is similar to phishing, which is when scammers attempt to get people to click on a link or button in an email or text message to download malware onto their devices or steal personal information from fake account or login web pages. With vishing, however, scammers use the old-fashioned phone call to try and steal from their victims, and a successful scam can cause big damage.

Take the situation that MGM Las Vegas found itself in over the summer: the company lost $52 million after their systems were shut down, and it all started with a 10-minute phone call. A member of a criminal group used the identity of an MGM employee found on LinkedIn, called the MGM internal help desk, and asked for a password change. The person working the desk complied, and the hacker was in the system with a fresh new password, ready to cause havoc.

It's important to never give out personal information to an unknown person over the phone, especially if you weren't expecting the call.