Varney asked McAfee to show how he thinks the Sony hackers were able to break into the company's computer systems and got an up-close and personal lesson.
From a remote location, McAfee hacked into Varney's phone via its voicemail, accessed the contacts and then faked a call from one of those contacts. When Varney's phone rang, it appeared to be an incoming call from Fox News headquarters.
Then, McAfee explained what he would do from there. Check out the clip above to see how it unfolded.
McAfee founded the software company that bears his name, but resigned from it in 1994. It's now a subsidiary of Intel.
(h/t Kevin Mitnick)