# Frida Tutorial 3

<details>

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<figure><img src="https://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-L_2uGJGU7AVNRcqRvEi%2Fuploads%2FwdlXOpyZOVGNzyhOiiFK%2Fimage%20(1).png?alt=media&#x26;token=13f4d279-7d3f-47ce-a68e-35f9a906973f" alt=""><figcaption></figcaption></figure>

​If you are interested in **hacking carer** and hack the unhackable - **we are hiring!** (*fluent polish written and spoken required*).

{% embed url="<https://www.stmcyber.com/careers>" %}

\\

***

**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:

```javascript
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:

```javascript
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.");
});
```

<figure><img src="https://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-L_2uGJGU7AVNRcqRvEi%2Fuploads%2FwdlXOpyZOVGNzyhOiiFK%2Fimage%20(1).png?alt=media&#x26;token=13f4d279-7d3f-47ce-a68e-35f9a906973f" alt=""><figcaption></figcaption></figure>

​​If you are interested in **hacking carer** and hack the unhackable - **we are hiring!** (*fluent polish written and spoken required*).

{% embed url="<https://www.stmcyber.com/careers>" %}

<details>

<summary><a href="https://www.twitch.tv/hacktricks_live/schedule"><strong>🎙️ HackTricks LIVE Twitch</strong></a> <strong>Wednesdays 5.30pm (UTC) 🎙️ -</strong> <a href="https://www.youtube.com/@hacktricks_LIVE"><strong>🎥 Youtube 🎥</strong></a></summary>

* 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**](https://github.com/sponsors/carlospolop)!
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
* **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).

</details>


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