According to leaked memo, Apple found 29 leakers last year and 12 were arrested13
Apple listed some of the actual information that was leaked. In one case, Apple cited a meeting led by Apple’s software engineering head Craig Federighi. During the meeting, Federighi noted that some software features for the iPhone would be delayed, and someone leaked that information to the media. Apple discovered the employee that leaked what was said at the meeting, and fired him.
In another case, details about an unreleased software package were leaked, which gave away secrets about the Apple iPhone X and the most recent Apple Watch prior to their introductions. Last year, Apple held an internal seminar called "Stopping Leakers - Keeping Confidential at Apple." Word about the seminar leaked, and secrets continued to pour out of the company. Apple says that digital forensics helped identify employees who passed along confidential information about the iPhone X, iPad Pro and AirPods directly to a particular phone blog (not us, by the way).
The company is also working with its suppliers to prevent theft of intellectual property, and to identify individuals who try to access information that they are not entitled to have. Despite this, information continues to make its way out of Apple. Just last month, an Apple employee who passed confidential information to the media pertaining to Apple's software roadmap, was caught and fired. When asked why he did it, he responded by saying that he didn't think he'd be caught.
Tech companies like Apple have the means to discover who is passing along confidential information. And Apple says that employees found to be leaking company secrets to the press will not only get fired, they could end up in jail and fined. The risk is entirely on the Apple employee who passes along the information.