UNDATED -- Smart phones will no doubt be hot gifts this Christmas. But security experts are warning it's easier than ever to break into someone's cell phone.
When you answer your cell phone, someone might be listening in.
All over the internet, companies are selling software that can bug your phone. Some sites even market it as a way to spy on your significant other.
"I'd like to think I could trust my friends or my boyfriend that they wouldn't do that," said cell phone user Jennifer Lynch.
But someone could swipe your phone - and in just a few minutes install the spyware - returning it without you ever knowing.
Then, when you get a call the spy can listen in to your conversations, and read your texts and e-mails.
The cell phone hacker can even access your camera phone and speaker, to keep track of your every move.
Experts say there are sometimes warning signs.
If the screen on your cell phone lights up for no reason, the flash goes off without taking a picture or the battery runs out quickly, your phone might have spyware on it.
And hackers have figured out how break into cell phone remotely through e-mail. Open it up and the spyware is installed.
"Hackers are now seeing these devices as a new way of making money. A new way of getting data about people," said Nigel Stanley, Security Expert.
Security experts suggest putting a password on your cell phone - and keeping it to yourself. And don't open e-mails unless you know who sent it.