Last week, news emerged that a small percentage of App Store apps on iOS devices have been infected by malware injected into versions of Xcode not directly downloaded from Apple’s website. In response to these hacks, Apple has today urged developers to validate their version of Xcode and ensure they only download new versions from Apple. The Cupertino-based company notified developers of the situation this morning via email:
We recently removed apps from the App Store that were built with a counterfeit version of Xcode which had the potential to cause harm to customers. You should always download Xcode directly from the Mac App Store, or from the Apple Developer website, and leave Gatekeeper enabled on all your systems to protect against tampered software.
When you download Xcode from the Mac App Store, OS X automatically checks the code signature for Xcode and validates that it is code signed by Apple. When you download Xcode from the Apple Developer website, the code signature is also automatically checked and validated by default as long as you have not disabled Gatekeeper.
Whether you downloaded Xcode from Apple or received Xcode from another source, such as a USB or Thunderbolt disk, or over a local network, you can easily verify the integrity of your copy of Xcode.
Apple has also posted a message to developers on its website with additional information. Apple has provided developers with a command line tool for validating that their version of Xcode is not infected. Apple also has recommended that developers install a clean copy of Xcode downloaded directly from Apple’s Developer Portal (via the Mac App Store) before submitting a new app or app update to the App Store.
In related news, Apple’s Phil Schiller told Sina that no malicious apps actually transmitted any user data: