Bloomberg) -- Finnish developer Janne Kytomaki said he knew something was amiss last year when he noticed dozens of best-selling applications on Google Inc.’s Android Market listing the same incorrect author.

Kytomaki ran tests, identified the mislabeled software as a fast-moving attack and published the findings online.

Google responded swiftly. It yanked the apps from the marketplace and, using a little-known tactic to keep the malware from spreading, flipped a kill switch that reached into more than 250,000 infected Android smartphones and removed all vestiges of the software.

“I was positively surprised by how fast Google got the apps removed from the market and how fast they were able to roll out a tool for removing the malware,” Kytomaki said.

Google, Apple Inc. and Microsoft Corp. have with little fanfare embraced technology that lets technicians instantly and remotely purge unauthorized content from users’ machines. So- called kill switches are standard on Android handsets and iPhones, the smartphone leaders. The capability will soon become more widespread with the release of Microsoft’s Windows 8 software for tablets and computers.

While their stated use is for the removal of harmful content, there’s no standard definition of what that means, and companies aren’t required to disclose when and how the tools are employed. The technology could be harnessed by a hacker to unleash a virus, a company to pry into a user’s private information or a government body to repress free speech, said Eric Goldman, director of the High Tech Law Institute at Santa Clara University’s law school.

‘Dictator-Philosopher-King’

“We have the benevolent dictator, philosopher-king type of model,” Goldman said. “You have someone who has absolute control over my hard drive in ways I may have never anticipated or consented to. If they use that power wisely, they actually make my life better. We don’t know if they use the power wisely. In fact, we may never know when they use their power at all.”

Kill switches are technologically unsophisticated administrative programs that run silently in the background. They have long existed in controlled networks, like at work, where technical staff has power over every machine. They haven’t been widely used on personal computers, whose users are online sporadically and inconsistently update security patches -- a failure that has fostered the spread of malware such as the Conficker worm, which has infected millions of Windows machines.

Smartphone users, on the other hand, are online all the time and must download applications from tightly controlled stores. By design, mobile software gives computer companies a second chance on security, said Kevin Mahaffey, co-founder of Lookout Inc., a San Francisco security firm for smartphones.

‘Overcorrection’

“The remote-removal tools are very much a response to the mistakes of the PC era,” Mahaffey said. “Whether or not it’s an overcorrection, I think history will tell us. It can be done right, but we as an industry need to tread carefully. It’s easy to imagine several dystopian futures that can arise from this.”

One concern is that Google, Microsoft and others could face external pressure to engage kill switches.

Governments are getting increasingly aggressive in demanding help from technology companies in censoring e-mail and the Internet, as BlackBerry maker Research In Motion Ltd. learned in 2010 when India, Saudi Arabia and the United Arab Emirates pressured it to open customer communications to inspection.

“If you build a control into a device that the manufacturer and carrier can control, it will be used by governments,” said Chris Wysopal, co-founder of Veracode Inc., a security firm in Burlington, Massachusetts.

Benefits, Drawbacks

Hackers are also getting more sophisticated at infiltrating protected networks, and privacy breaches are more common as personal data becomes the coin of the Internet realm. A kill switch feature carries clear benefits, and potentially dangerous drawbacks, Wysopal said.

“It can really be used to add security, but it can also be used to deny people their rights to communicate,” he said. “This is a place where there’s no clear doctrine. We haven’t heard anything clearly come out from an Apple or a Google saying, ‘Here’s when we’ll use our kill switch and when we won’t.’”

Representatives of Mountain View, California-based Google and Microsoft, based in Redmond, Washington, said they have used kill switches a handful of times, though they declined to provide specifics.

Tricking ‘Twilight’ Fans

The kill switch is reserved for “really egregious, really obvious cases” of harmful content, said Hiroshi Lockheimer, Google’s vice president of Android engineering.

“We’ve always viewed remote removal as the final option,” he said. “It’s not something we want to use.”

One instance came after Jon Oberheide, a 28-year-old security researcher from Ann Arbor, Michigan, duped fans of the “Twilight” teen vampire movies. Oberheide uploaded a fake app on the Android Market and billed it as a preview of the latest film in the series. The software was empty, except for a single screen shot.

Still, the app, which had been downloaded 200 times, provided an entrée that might have let Oberheide introduce malware onto devices. It also helped Oberheide goad Google into using its kill-switch option.

“It finally happened,” Oberheide said.

Google, taking a lesson from PC industry bouts with malware, has built in more aggressive protections since the first versions of Android, which began appearing in phones in 2008. Google’s partners have sold more than 250 million Android devices, while Apple has sold more than 180 million iPhones.

Hacking Risk

Security experts said users would be at risk if hackers were able to hijack the mechanism Google uses to push software to the devices. Lockheimer said Google takes security of the mechanism seriously and has built-in protections.

Microsoft, which enabled the feature in Windows smartphones several years ago, said its takedowns have not involved malware. The violations concerned “technical issues and content issues,” said Todd Biggs, a director of product management at Microsoft.

“Revocation is a last resort, and it’s uncommon,” Biggs said. “We take that as a signpost that we’re on target toward our goal, which is safe, reliable apps for consumers.”

Microsoft disclosed last year that it was adding a kill switch to desktop and laptop software. It did so by posting the terms of use for an application store, a new feature for Windows 8.

Amazon’s ‘1984’ Moment

RIM’s licensing documents for vendors say that RIM reserves the right to remove applications from users’ devices “for any reason whatsoever.” Marisa Conway, a spokeswoman for Waterloo, Ontario-based RIM, declined to comment.

Tom Neumayr, a spokesman for Cupertino, California-based Apple, also declined to comment. Steve Jobs, Apple’s deceased co-founder, confirmed the existence of a kill switch in a 2008 interview with the Wall Street Journal. Jobs said it would be “irresponsible” for Apple not to have a way to protect users from malicious applications. The comment appeared at the bottom of a story about iPhone app sales, in response to research that uncovered clues that such a feature existed on Apple devices.

The incident that encapsulates the danger of using a kill switch is Amazon.com Inc.’s use of the feature to delete some copies of George Orwell’s “1984” and “Animal Farm” novels from Kindle devices in 2009 after discovering a publisher had sold them without the necessary rights.

‘Stupid, Thoughtless, Out of Line’

Customers were infuriated, and CEO Jeff Bezos called it “stupid, thoughtless and painfully out of line with our principles.” The company vowed it would never delete books from Kindles again.

Amazon representatives didn’t respond to requests for comment.

While the emergence of kill switches shows the growing control that technology companies have assumed over users’ devices, it also exposes the shortcomings of other methods of keeping users’ computers clean.

Stephanie Stambaugh, a 47-year-old freelance writer from Denver, has been battling a so-called botnet infection on her home PCs since December. Her Internet provider, Comcast Corp., alerted her to the infection, a type of program where a machine is controlled without the user’s consent that is becoming more common. She said that while she has run a dozen different antivirus and other cleanup programs, she is still getting alerts that her machine is infected.

Giving Up Privacy

Stambaugh said she can’t afford the $130 virus cleanup service that Comcast offers, and is considering reinstalling her operating software, the nuclear option of virus cleanups.

Cable-network operators such as Comcast have insight into which computers are compromised, since they can see when machines are silently reaching out to malicious sites. Yet they don’t have the same capabilities as companies such as Google, Microsoft and Apple. Aside from alerting customers, they are limited to quarantining poisoned computers, or restricting the amount of bandwidth they consume.

Cathy Avgiris, a senior vice president for Philadelphia- based Comcast, said fully cleaning an infection is tedious, imprecise work, since the most harmful programs are good at hiding themselves. She said Comcast would be leery of adopting a kill-switch function for that reason.

Even some security experts who see the value of a kill switch say its advantages don’t outweigh the potential risks.

“For most users, the ability to remotely remove apps is a good thing,” said Charlie Miller, a hacker of Apple products and a researcher at the security firm Accuvant Inc. However, “I don’t really like Google or anybody else with the ability to tell me what apps I can run or can’t run and to remotely manage my devices. For me, the added payoff of security doesn’t make up for the control and privacy you give up.”