[phyrrus9]

Sure, they aren't difficult given a few prerequisites (not on iOS 10, jailbroken or running internal build, dyld patches installed). however, you aren't going to get much from them. You would need a new code base for every major build and would have to ensure that they don't update (unless using something like libTIFF injection). Doing anything remote is out of the question in iOS, you don't have the skill or the time, but if you wanted to make one from scratch you would need a HUGE understanding of Aarch64 and Mach.