welcome back to "the lead." we have some more breaking news now in a new security breach. u.s. officials now very worried that hackers working for a foreign government may have spied on the u.s. government and private companies for the past three years in a new case. let's get right to cnn justice reporter evan perez. evan, what can you tell us? >> well, jake, one u.s. official described this as a thief stealing a master key to every government building. we're talking about juniper networks. this is a major manufacturer of routers and computer network equipment that supplies the u.s. government, everybody from the department of defense, pentagon, the fbi and justice department, treasury department. now, what they've discovered they discovered this yesterday -- well, they announced it yesterday, was apparently hackers had got into their systems and had rewritten the source code for some of this very important software that allows for encryption of communications. so this is very important not