lower, operating system level, experts said. It is now still possible for hackers to construct a file that appears to be a safe file type, such as an image or movie, but is actually an application." Apple confirmed that it was still possible to disguise files. "It is definitely possible on the Mac and on any platform to create an application and try to pretend that it is something that its not. That's the definition of Trojans," Philip Schiller, Apple's senior vice-president of worldwide product marketing, told ZDnet in an interview. "There are Trojans in the world, I have yet to see a successful one on the Mac, but there are such things in the world as Trojans." Experts say that Apple's patch was the first step and that it must release other updates to address the core problem. "Apple's security fix is an important first step, said Michael Lehn, doctoral candidate and research assistant at the University of Ulm in Germany. 'I think Apple did the right thing,' said Lehn, who first disclosed the Mac OS X vulnerability. 'The fact that a script gets executed automatically had to be fixed immediately. They just have to go further.'" The warning is not enough for many users, according to readers and the 'download and install' problem has plagued Mac OS X for a few years, according to the report.