cryptax / misc-code

Miscellaneous code
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jeb2frida Uses Function Alias Instead of Native Function Name #1

Closed H0r53 closed 7 months ago

H0r53 commented 2 years ago

If I rename a function or class in JEB and use the jeb2frida script to generate a Frida hook, the alias I used when renaming the function/class is included in the jeb2frida output instead of the actual class/function name in the APK. Clearly, the Frida runtime will be unable to hook routines that I've renamed with JEB since the app runtime uses the native names. This also occurs with obfuscated code using unicode function/class names outside of the printable range of characters.

Example, JEB tells me a function is defined as this when I hover my cursor over it

Class: class:Lum/\u1ADC\u1ADD;
  Method: method:um.\u1ADC\u1ADD.\u1ADD

However, JEB auto generated names for this class for me (otherwise the names where []). When I use the jeb2frida script I received this:

Java.perform(function() {
  var jeb2frida_class_MTH50910 = Java.use('um.CLS711');
  var jeb2frida_method_MTH50910 = jeb2frida_class_MTH50910.MTH50910;
  jeb2frida_method_MTH50910.implementation = function() {
    console.log('[MTH50910] Hooking um.CLS711.MTH50910(  ):);
    var ret = this.MTH50910();
    console.log('[MTH50910] returns '+ret);
    return ret;
  };
});

In this particular case, I think I needed

Java.perform(function() {
  var jeb2frida_class_MTH50910 = Java.use('um/\u1ADC\u1ADD');
  var jeb2frida_method_MTH50910 = jeb2frida_class_MTH50910['\u1ADD'];
  jeb2frida_method_MTH50910.implementation = function() {
    var ret = this['\u1ADD']();
    return ret;
  };
});

This is reproducible by simply renaming a function in JEB and using the jeb2frida script on that function. The produced code uses the new function name instead of the natural one (which is required for Frida to successfully hook it).

Can the jeb2frida script be updated to use the native names of functions/classes?

cryptax commented 2 years ago

Ah yes, this is a bug indeed. I need to fix it.

cryptax commented 7 months ago

You should be using GenerateFridaSnippetForDex.py from https://github.com/pnfsoftware/jeb-samplecode/blob/master/scripts/GenerateFridaSnippetForDex.py. However, there is a small error in that one too. Be sure to apply patch https://github.com/pnfsoftware/jeb-samplecode/pull/7