owaspuncrackable-1.md

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From: https://joshspicer.com/android-frida-1
APK: https://github.com/OWASP/owasp-mstg/blob/master/Crackmes/Android/Level_01/UnCrackable-Level1.apk

Solution 1

Based in https://joshspicer.com/android-frida-1

**Hook the **exit() function and decrypt function so it print the flag in frida console when you press verify:

Java.perform(function () {
  send("Starting hooks OWASP uncrackable1...");

  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 : " + getString(ret));

    var flag = "";
    for (var i=0; i < ret.length; i++){
      flag += String.fromCharCode(ret[i]);
    }
    send("Decrypted flag: " + flag);
    return ret; //[B
  };

  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  :)");
  };

  send("Hooks installed.");
});

Solution 2

Based in https://joshspicer.com/android-frida-1

Hook rootchecks and decrypt function so it print the flag in frida console when you press verify:

Java.perform(function () {
  send("Starting hooks OWASP uncrackable1...");

  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 : " + getString(ret));

    var flag = "";
    for (var i=0; i < ret.length; i++){
      flag += String.fromCharCode(ret[i]);
    }
    send("Decrypted flag: " + flag);
    return ret; //[B
  };

  var rootcheck1 = Java.use("sg.vantagepoint.a.c");
  rootcheck1.a.overload().implementation = function() {
    send("sg.vantagepoint.a.c.a()Z   Root check 1 HIT!  su.exists()");
    return false;
  };

  var rootcheck2 = Java.use("sg.vantagepoint.a.c");
  rootcheck2.b.overload().implementation = function() {
    send("sg.vantagepoint.a.c.b()Z  Root check 2 HIT!  test-keys");
    return false;
  };

  var rootcheck3 = Java.use("sg.vantagepoint.a.c");
  rootcheck3.c.overload().implementation = function() {
    send("sg.vantagepoint.a.c.c()Z  Root check 3 HIT!  Root packages");
    return false;
  };

  var debugcheck = Java.use("sg.vantagepoint.a.b");
  debugcheck.a.overload("android.content.Context").implementation = function(var_0) {
    send("sg.vantagepoint.a.b.a(Landroid/content/Context;)Z  Debug check HIT! ");
    return false;
  };

  send("Hooks installed.");
});

Support HackTricks and get benefits!

• Do you work in a cybersecurity company? Do you want to see your company advertised in HackTricks? or do you want to have access to the latest version of the PEASS or download HackTricks in PDF? Check the SUBSCRIPTION PLANS!

• Discover The PEASS Family, our collection of exclusive NFTs

• Get the official PEASS & HackTricks swag

• Join the 💬 Discord group or the telegram group or follow me on Twitter 🐦@carlospolopm.

• Share your hacking tricks by submitting PRs to the hacktricks github repo.