Install frida tools:
pip install frida-toolspip install frida
Download and install in the android the frida server (Download the latest release). One-liner to restart adb in root mode, connect to it, upload frida-server, give exec permissions and run it in backgroud:
adb root; adb connect localhost:6000; sleep 1; adb push frida-server /data/local/tmp/; adb shell "chmod 755 /data/local/tmp/frida-server"; adb shell "/data/local/tmp/frida-server &"
Check if it is working:
frida-ps -U #List packages and processesfrida-ps -U | grep -i <part_of_the_package_name> #Get all the package name
From: https://medium.com/infosec-adventures/introduction-to-frida-5a3f51595ca1 APK: https://github.com/t0thkr1s/frida-demo/releases Source Code: https://github.com/t0thkr1s/frida-demo​
Follow the link to read it.
From: https://11x256.github.io/Frida-hooking-android-part-2/ (Parts 2, 3 & 4) APKs and Source code: https://github.com/11x256/frida-android-examples​
Follow the link to read it.​
From: https://joshspicer.com/android-frida-1 APK: https://github.com/OWASP/owasp-mstg/blob/master/Crackmes/Android/Level_01/UnCrackable-Level1.apk​
Follow the link to read it. You can find some Awesome Frida scripts here: https://codeshare.frida.re/​
Here you can find the more basic and interesting functionalities of Frida to make a quick script:
frida-ps -U​#Basic frida hookingfrida -l disableRoot.js -f owasp.mstg.uncrackable1​#Hooking before starting the appfrida -U --no-pause -l disableRoot.js -f owasp.mstg.uncrackable1#The --no-pause and -f options allow the app to be spawned automatically,#frozen so that the instrumentation can occur, and the automatically#continue execution with our modified code.
import frida, sys​jscode = open(sys.argv[0]).read()process = frida.get_usb_device().attach('infosecadventures.fridademo')script = process.create_script(jscode)print('[ * ] Running Frida Demo application')script.load()sys.stdin.read()
Hook the function a()
of the class sg.vantagepoint.a.c
Java.perform(function () {; rootcheck1.a.overload().implementation = function() {rootcheck1.a.overload().implementation = function() {send("sg.vantagepoint.a.c.a()Z Root check 1 HIT! su.exists()");return false;};});
Hook java exit()
var sysexit = Java.use("java.lang.System");sysexit.exit.overload("int").implementation = function(var_0) {send("java.lang.System.exit(I)V // We avoid exiting the application :)");};
Hook MainActivity .onStart()
& .onCreate()
var mainactivity = Java.use("sg.vantagepoint.uncrackable1.MainActivity");mainactivity.onStart.overload().implementation = function() {send("MainActivity.onStart() HIT!!!");var ret = this.onStart.overload().call(this);};mainactivity.onCreate.overload("android.os.Bundle").implementation = function(var_0) {send("MainActivity.onCreate() HIT!!!");var ret = this.onCreate.overload("android.os.Bundle").call(this,var_0);};
Hook android .onCreate()
var activity = Java.use("android.app.Activity");activity.onCreate.overload("android.os.Bundle").implementation = function(var_0) {send("Activity HIT!!!");var ret = this.onCreate.overload("android.os.Bundle").call(this,var_0);};
Hooking a decryption function. Print the input, call the original function decrypt the input and finally, print the plain data:
function getString(data){var ret = "";for (var i=0; i < data.length; i++){ret += data[i].toString();}return ret}var aes_decrypt = Java.use("sg.vantagepoint.a.a");aes_decrypt.a.overload("[B","[B").implementation = function(var_0,var_1) {send("sg.vantagepoint.a.a.a([B[B)[B doFinal(enc) // AES/ECB/PKCS7Padding");send("Key : " + getString(var_0));send("Encrypted : " + getString(var_1));var ret = this.a.overload("[B","[B").call(this,var_0,var_1);send("Decrypted : " + ret);​var flag = "";for (var i=0; i < ret.length; i++){flag += String.fromCharCode(ret[i]);}send("Decrypted flag: " + flag);return ret; //[B};
Hook a function that receives a string and call it with other string (from here)
var string_class = Java.use("java.lang.String"); // get a JS wrapper for java's String class​my_class.fun.overload("java.lang.String").implementation = function(x){ //hooking the new functionvar my_string = string_class.$new("My TeSt String#####"); //creating a new String by using `new` operatorconsole.log("Original arg: " +x );var ret = this.fun(my_string); // calling the original function with the new String, and putting its return value in ret variableconsole.log("Return value: "+ret);return ret;};
If you want to extract some attribute of a created object you can use this.
In this example you are going to see how to get the object of the class my_activity and how to call the function .secret() that will print a private attribute of the object:
Java.choose("com.example.a11x256.frida_test.my_activity" , {onMatch : function(instance){ //This function will be called for every instance found by fridaconsole.log("Found instance: "+instance);console.log("Result of secret func: " + instance.secret());},onComplete:function(){}});