NEW YORK (AP) -- Home computer users who believe hacking is a threat only to government and corporate networks need to realize that the Internet puts them at risk of being invaded by computer predators, too, security experts say.

Concern about home security grew Thursday following disclosure that former CIA Director John Deutch stored sensitive national security secrets on a home computer connected to the Internet."He certainly should have known better," said Cormac Foster, who monitors security issues for Internet research firm Jupiter Communications. "If your business is protecting the security of the country, one would hope you wouldn't make a mistake like that."

Elias Levy, chief technology officer for, said hackers often target computers randomly, to obtain financial information or play a prank. But sometimes they access home machines from which they launch attacks on companies.

"It comes down to people thinking, I don't have anything important on my computer, so why would somebody want to get me," Levy said.

A hacker can gain access to a home computer in many ways.

If a sharing option is turned on, outsiders could take advantage of that to delete or steal files. Through e-mail, hackers could send viruses and other malicious programs that will give them access to sensitive documents.

The risks are greater with high-speed connections such as cable modems -- those computers are always connected to the Internet.

But even standard, dial-up users are vulnerable. Hackers have tools that can automatically scan the Web looking for computers with security holes.

"If I'm a burglar, I have to rattle each door in the neighborhood until I find one that's unlocked," said Tom Powledge, senior product manager for Norton Internet Security software. A hacker with the right scanning tools "can rattle hundreds of doors at once."

Once in, a hacker can seize control of the computer, even stealing credit card numbers or top-secret materials.

CIA Director George Tenet said he has no evidence that foreign enemies hacked into Deutch's computer but acknowledged there is no way to tell for sure.