5 ms·

I'm curious how one would reverse engineer and acquire the source code? Not looking to do anything illegal, just wondering what goes into making such duplicate

by navs 13y ago

I'm curious how one would reverse engineer and acquire the source code? Not looking to do anything illegal, just wondering what goes into making such duplicate apps.

ipodize 13y ago
I'm quite sure that they are merely replacing some of the application's image resources and resigning it... But I could be wrong.
- jonlipsky 13y ago
  Correct, they are simply updating the image resources and resigning the app. The code hasn't been touched (though the code is from a two year old version of the app).
  - chj 13y ago
    I think we could add some detection to in the code that if the bundle id doesn't match, then app should display a warning.
    - navs 13y ago
      Correct me if I'm wrong but doesn't the .ipa include the bundle ID as well as the App ID inside the binary? I didn't think it was possible to edit that and still get it codesigned for approval.
      - jonlipsky 13y ago
        Unfortunately, the bundle id is just stored in a plist file, and it's actually quite easy to re-sign an app bundle with a different profile after modifying it.
        aqrashik 13y ago
        Would checking the value of [[NSBundle mainBundle] bundleIdentifier] with a hardcoded value help? It would be a bit more code, but just a few lines of verification code when the application launches and the app can refuse to start up if the value doesn't match. Someone dedicated would still be able to crack it, but it would at least require some effort on the part of the fraudster
peterkelly 13y ago
They use a jailbroken device to obtain a decrypted copy of the application binary, then re-sign it with their own developer certificate, and submit. There's no recompilation needed.
kybernetyk 13y ago
You don't need the code. You just change some strings in the binary/bundle (if you're fancy), sign it with your certificate and upload to the app store.
deleted 13y ago
[deleted]
jakejake 13y ago
Apple apps are basically just a special folder that contain a combination of compiled files and uncompiled "resources" which can include images and even some of the config files. You can easily browse any native app on a Mac by just ctrl+clicking it and selecting "show package contents" These cloners are just replacing image files and changing some text in config files which requires almost zero programming or reverse engineering skill.

by navs 13y ago

I'm curious how one would reverse engineer and acquire the source code? Not looking to do anything illegal, just wondering what goes into making such duplicate apps.

ipodize 13y ago

I'm quite sure that they are merely replacing some of the application's image resources and resigning it... But I could be wrong.

jonlipsky 13y ago
Correct, they are simply updating the image resources and resigning the app. The code hasn't been touched (though the code is from a two year old version of the app).
- chj 13y ago
  I think we could add some detection to in the code that if the bundle id doesn't match, then app should display a warning.
  - navs 13y ago
    Correct me if I'm wrong but doesn't the .ipa include the bundle ID as well as the App ID inside the binary? I didn't think it was possible to edit that and still get it codesigned for approval.
    - jonlipsky 13y ago
      Unfortunately, the bundle id is just stored in a plist file, and it's actually quite easy to re-sign an app bundle with a different profile after modifying it.
      - aqrashik 13y ago
        Would checking the value of [[NSBundle mainBundle] bundleIdentifier] with a hardcoded value help? It would be a bit more code, but just a few lines of verification code when the application launches and the app can refuse to start up if the value doesn't match. Someone dedicated would still be able to crack it, but it would at least require some effort on the part of the fraudster

peterkelly 13y ago

They use a jailbroken device to obtain a decrypted copy of the application binary, then re-sign it with their own developer certificate, and submit. There's no recompilation needed.

kybernetyk 13y ago

You don't need the code. You just change some strings in the binary/bundle (if you're fancy), sign it with your certificate and upload to the app store.

deleted 13y ago

[deleted]

jakejake 13y ago

Apple apps are basically just a special folder that contain a combination of compiled files and uncompiled "resources" which can include images and even some of the config files. You can easily browse any native app on a Mac by just ctrl+clicking it and selecting "show package contents" These cloners are just replacing image files and changing some text in config files which requires almost zero programming or reverse engineering skill.