INSIDE EDITION witnessed first-hand how easy it is for one guy to break into your hotel room.
In seconds he hacked the electronic door lock without using a hotel keycard—just a small homemade device in the palm of his hand.
Cody Brocious is the computer hacker who first discovered the shocking security flaw that everyone who stays in a hotel needs to know.
Brocious told INSIDE EDITION's Megan Alexander, "There's a little hole on the bottom of the lock where you just plug that [the hand-held device] in and the lock just opens. Nothing to it."
The problem centers on a particular model of hotel door lock that can often be found at Holiday Inns and other major hotel chains. The lock is made by Onity, whose website describes itself as the "the world's leading provider of electronic locks."
Alexander asked Brocious, "People are in danger that somebody could break into their room easily?"
"People are absolutely in danger with this," said Brocious.
Brocious' alarming discovery is spreading like wildfire over the internet, spawning YouTube videos that show how to make your own device to hack electronic hotel locks.
One device is disguised as a plain magic marker and simply plugs into the bottom of the hotel lock.
Pat Brosnan, CEO of Brosnan Risk Communications, showed INSIDE EDITION how a hacker could easily go door-to-door to every room on a floor. We asked him what you can do to protect yourself in a hotel room.
"You've got to use common sense. Leave your valuables in a safe. Don't leave them in a room," said Brosnan.
And he says if you think that metal latch on the door is sufficient security, think again.
Brosnan took a close look at one metal latch and said, "Look at this—the screws are backed out. A kid could push this door in."
A spokesperson for Onity says: "Onity places the highest priority on the safety and security provided by its products. Onity is aware that a hacker has presented complex methods to illegally break into locks. The company is working with its customers to deploy solutions that have been validated by independent experts. All customer requests for these solutions have already been fulfilled or are in the process of being fulfilled."
But until all these hotel locks are fixed, listen to what our security expert says:
"You can't think for one second that you're safe and secure in a hotel room today. This is a real nightmare," said Brosnan.
There is still no word on how many locks remain vulnerable. Meantime, the parent company of Holiday Inn told us their hotels are working with Onity to expedite the fix to the locks. And they say the hotel we went to should receive the parts needed to correct the problem by today.