A Chinese site called Kuaiyong has seen a surge in popularity following the closure of Hackulous. Using a mobile or desktop application users can simply search for and install apps without paying for them.
The apps appear to have been purchased under an Apple enterprise license, which allows for installation to multiple devices. There could also be a bundle of smaller developer accounts being used, which max out at 100 ‘slots’. They are then being re-distributed to other users through the two tools. There are some indications, however, that the issues go further than a single enterprise license.
TNW notes that Kuaiyong is distributing the exact same copy of an app with the same set of (encrypted) credentials. It suggests that perhaps they've figured out a way to bypass Apple's licensing rules to redistribute the same copy of an application over and over.
Another service called Zeusmos is also distributing cracked apps utilizing a developer licensing certificate and actually charging users for the service. TNW believes that they may have found a way to 'ease the process of purchasing a developer slot' which Apple has clearly indicated is against their terms of service.
Hopefully, Apple will take notice and address the problem as soon as possible. We strongly suggest you support the developers who work incredible hard to create the many apps available for iOS and OS X.