U.S. Maj. Gen. Harold Greene was visiting an Afghan military training academy Tuesday when he was shot dead by an Afghan soldier, who was subsequently killed. Afghan troops who knew the attacker say he disliked the Taliban and they aren't sure what his motive was. U.S. Army/Getty Images hide caption

itoggle caption U.S. Army/Getty Images

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