Reuters reports that Apple is cleaning up hundreds of malicious iOS apps after what is described as the first major attack on its App Store. Hundreds of the stores apps were infected with malware called XcodeGhost, which used as a vector a counterfeit version of iOS IDE Xcode. Things could be a lot worse, though: Palo Alto Networks Director of Threat Intelligence Ryan Olson said the malware had limited functionality and his firm had uncovered no examples of data theft or other harm as a result of the attack. Still, he said it was "a pretty big deal" because it showed that the App Store could be compromised if hackers infected machines of software developers writing legitimate apps. Other attackers may copy that approach, which is hard to defend against, he said.