"I can dial into an elevator phone, listen in on private conversations, reprogram the phone so that if someone hits it in an emergency it calls a number of my choosing," Caruana told me in our first conversation. [...]
Call up most elevator phones and press 2, and you'll be asked to enter a password to reprogram them. In far too many cases, Caruana says, phone installers and building managers don't change those passwords from easily guessable default codes, allowing anyone to tamper with their settings.
Inside The Hidden World Of Elevator Phreaking: