By JEFF KAROUB and MATTHEW BROWN / Associated Press
DETROIT (AP) -- Warnings about zombies may seem amusing, but officials say they're dead serious about figuring out who hacked into public warning systems in the United States to broadcast such messages.
So far, people in California, Michigan, Montana and New Mexico have heard the warnings about zombies over the Emergency Alert System.
The subject matter may be humorous. But Greg MacDonald with the Montana Broadcasters Association said the consequences of such an attack could be severe.
In Michigan, hackers broke into the system with audio or text messages at two stations on Monday. Michigan Association of Broadcasters President Karole White said the breach appeared to be related to default passwords that the stations hadn't changed.
The Federal Communications Commission urged stations to reset passwords and take other steps to protect themselves.