By Jim Finkle BOSTON (Reuters) - Apple Inc customers were targeted by hackers over the weekend in the first campaign against Macintosh computers using a pernicious type of software known as ransomware, researchers with Palo Alto Networks Inc told Reuters on Sunday. Ransomware, one of the fastest-growing types of cyber threats, encrypts data on infected machines, then typically asks users to pay ransoms in hard-to-trace digital currencies to get an electronic key so they can retrieve their data.