Popular enterprise software company Citrix that provides services to the U.S. military, the FBI, many U.S. corporations, and various U.S. government agencies disclosed last weekend a massive data breach of its internal network by "international cyber criminals." Citrix said it was warned by the FBI on Wednesday of foreign hackers compromising its IT systems and stealing "business documents," adding that the company does not know precisely which documents the hackers obtained nor how they got in.