Behind Your Business

Mobile phones are becoming ever more like personal computers. That means they are also becoming more vulnerable to traditional computer menaces like hackers and viruses.

This year, the Russian anti-virus company Kaspersky Lab reported on a new malicious program that stole money by taking over Nokia phones and making small charges to the owners' wireless accounts.

Then last month, an Australian student created an experimental worm that hopscotched across so-called "jailbroken" iPhones, which their owners have altered so they can run software Apple has not authorized.

The mischievous worm did not cause any damage -- it just installed a photo of the '80s pop star Rick Astley. But to security experts, it suggested that more serious attacks on iPhones were possible.

Jeff Moss, a security expert, said mobile viruses had recently become more common in Asia.

"The tipping point will be when we're using the phone to shop and conduct banking," Mr. Moss said. "The more you do with the phone, the more valuable a target it becomes."

Where there are perceived security threats, there are always entrepreneurs and investors looking to capitalize on them -- and build profitable businesses. This month Khosla Ventures, a respected Silicon Valley venture capital firm, led an investment group that injected $5.5 million into a security start-up called Lookout.

Lookout, based in San Francisco, was previously a consulting firm called Flexilis run by recent graduates of the University of Southern California. Now it wants to be the security giant of the mobile world, similar to the role Symantec plays in the desktop computer market.

This year, Lookout began testing security software for phones running the Windows Mobile and Android operating systems, and it will soon introduce security applications for the BlackBerry and iPhone. The software protects phones against rogue programs and gives phone owners the ability to remotely back up and erase...