U.S. intelligence officials believe North Korea was centrally involved in the recent attack on Sony Pictures' computer network — possibly out of retribution for its film The Interview. Above, a security guard stands outside a theater during the film's premiere in Los Angeles last week. Kevork Djansezian/Reuters/Landov hide caption

itoggle caption Kevork Djansezian/Reuters/Landov

Kmart says it has removed malware that had infected its checkout registers in stores. The company believes the malware may have been in place for about a month before it was detected. Rachel Murray/Getty Images hide caption

itoggle caption Rachel Murray/Getty Images

Security expert Jose Molina discovered he could control "every device in every room" of a luxury hotel in China. Aarti Shahani/NPR hide caption

itoggle caption Aarti Shahani/NPR

After Grant Hernandez, an undergraduate security researcher at the University of Central Florida, hacked Nest, he programmed it to riff off a favorite line from the movie 2001: A Space Odyssey. Aarti Shahani/NPR hide caption

itoggle caption Aarti Shahani/NPR

Cybersecurity researcher Ruben Santamarta says he has figured out how to hack the satellite communications equipment on passenger jets through their Wi-Fi and in-flight entertainment systems. Andrea Comas/Reuters/Landov hide caption

itoggle caption Andrea Comas/Reuters/Landov

Target Co. estimates that at least 70 million individuals may have had information including their "names, mailing addresses, phone numbers or email addresses" stolen in a recent data breach. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

The logo and a page of mobile app "Snapchat" are displayed on tablets. Hackers broke into Snapchat, the popular mobile app, accessing the phone numbers and usernames of 4.6 million users and publishing them online. Lionel Bonaventure/AFP/Getty Images hide caption

itoggle caption Lionel Bonaventure/AFP/Getty Images

The Toyota Prius, seen here at the New York International Auto Show in March, was one of the cars security experts Chris Valasek and Charlie Miller showed to be susceptible to attacks by hackers. Mike Segar /Reuters /Landov hide caption

itoggle caption Mike Segar /Reuters /Landov

An image of the site promoting Def Con 21, a large annual gathering of hackers in Las Vegas. The meeting's leader is asking federal workers to stay away from this year's event. Def Con hide caption

itoggle caption Def Con