The words written in the front

Origin of things

  • I saw a message on Wechat. In order to express his cute girl "Zhao Qianmeng", the local Harrow Bike iOS client displays the vehicle icon near the user as his own picture. The picture reads Zhao Qianmeng, I love you
  • Source map
  • Then I saw a lot of questions in the comments section
    • Did he hack the server?
    • Is he a picture of himself?
    • Did he reverse engineer his standalone App?

These comments intrigued me

  • My answer to the comment
    • First reject intrusion on the server (because it is illegal.. Cloud’s predecessors are a cautionary tale, though they only infiltrate)
    • Then reject the P diagram. Vindicate this kind of big thing through the P diagram! (Without sincerity, it is easy to fail. 2. There are many P pictures every day, but they will not be widely spread. Most boys can't photoshop)
    • By elimination, he’s obviously reversed his App

So why am I going the other way?

  • If he can reverse modify it, it means I can reverse modify it.Although I don't have the need to express my feelings at the moment, I don't know if I will in the future. Or one of the boys might need my help)

The following shows the results of reverse modification of x bike through iOS

  • On a graph

  • Because people said the first picture was not pretty. So let’s do the last picture

So let’s talk a little bit about the reverse process

Step 1: Static analysis

  • Hooper 或者 IDA

Step 2 dynamic debugging

  • LLDB 或者 cycript

Step 3 pack and re-sign

  • MonkeyDev 或者 IPAPatch

Why is the reverse process so easy? Didn’t write anything

  • Because this is a simple, regular App

Finally, show me the modified code

%hook MAAnnotationView

-(void)setImage:(id)arg1 {
%log;
// UIImage *image = [UIImage ima]

UIImage *image = [UIImage imageNamed:@"yuzhouheikewll.png"];
arg1 = image;
NSLog(@"yuzhouheikewll::==%@", image);
%orig;

}

%end
Copy the code

The last

  • Thank you for reading my article in your busy schedule