Security firm Bit9 has been hacked by hackers using stolen certificates to sign malware. The company is investigating the source of the breach, but it is still investigating. At least three of its customers were sent malware that was digitally signed with Bit9s certificate. It is not the first time that hackers have breached a security firm as part of a sophisticated scheme to access data at one of their customers. The use of such a technique has been used in the past in the case of Stuxnet, the terrible cyber weapon.”]