mirror of
https://github.com/carlospolop/hacktricks
synced 2024-12-22 11:03:24 +00:00
131 lines
4 KiB
Markdown
131 lines
4 KiB
Markdown
# Frida Tutorial 1
|
|
|
|
**From**: [https://medium.com/infosec-adventures/introduction-to-frida-5a3f51595ca1](https://medium.com/infosec-adventures/introduction-to-frida-5a3f51595ca1)
|
|
**APK**: [https://github.com/t0thkr1s/frida-demo/releases](https://github.com/t0thkr1s/frida-demo/releases)
|
|
**Source Code**: [https://github.com/t0thkr1s/frida-demo](https://github.com/t0thkr1s/frida-demo)
|
|
|
|
## Python
|
|
|
|
Frida allows you to **insert JavaScript code** inside functions of a running application. But you can use **python** to **call** the hooks and even to **interact** with the **hooks**.
|
|
|
|
This is a easy python script that you can use with all the proposed examples in this tutorial:
|
|
|
|
```python
|
|
#hooking.py
|
|
import frida, sys
|
|
|
|
with open(sys.argv[1], 'r') as f:
|
|
jscode = f.read()
|
|
process = frida.get_usb_device().attach('infosecadventures.fridademo')
|
|
script = process.create_script(jscode)
|
|
print('[ * ] Running Frida Demo application')
|
|
script.load()
|
|
sys.stdin.read()
|
|
```
|
|
|
|
Call the script:
|
|
|
|
```bash
|
|
python hooking.py <hookN.js>
|
|
```
|
|
|
|
It is useful to know how to use python with frida, but for this examples you could also call directly Frida using command line frida tools:
|
|
|
|
```text
|
|
frida -U --no-pause -l hookN.js -f infosecadventures.fridademo
|
|
```
|
|
|
|
## Hook 1 - Boolean Bypass
|
|
|
|
Here you can see how to **hook** a **boolean** method \(_checkPin_\) from the class: _infosecadventures.fridademo.utils.PinUtil_
|
|
|
|
```javascript
|
|
//hook1.js
|
|
Java.perform(function() {
|
|
console.log("[ * ] Starting implementation override...")
|
|
var MainActivity = Java.use("infosecadventures.fridademo.utils.PinUtil");
|
|
MainActivity.checkPin.implementation = function(pin){
|
|
console.log("[ + ] PIN check successfully bypassed!")
|
|
return true;
|
|
}
|
|
});
|
|
```
|
|
|
|
```text
|
|
python hooking.py hook1.js
|
|
```
|
|
|
|
Mirar: La funcion recibe como parametro un String, no hace falta overload?
|
|
|
|
## Hook 2 - Function Bruteforce
|
|
|
|
### Non-Static Function
|
|
|
|
If you want to call a non-static function of a class, you **first need a instance** of that class. Then, you can use that instance to call the function.
|
|
To do so, you could **find and existing instance** and use it:
|
|
|
|
```javascript
|
|
Java.perform(function() {
|
|
console.log("[ * ] Starting PIN Brute-force, please wait...");
|
|
Java.choose("infosecadventures.fridademo.utils.PinUtil", {
|
|
onMatch: function(instance) {
|
|
console.log("[ * ] Instance found in memory: " + instance);
|
|
for(var i = 1000; i < 9999; i++){
|
|
if(instance.checkPin(i + "") == true){
|
|
console.log("[ + ] Found correct PIN: " + i);
|
|
break;
|
|
}
|
|
}
|
|
},
|
|
onComplete: function() { }
|
|
});
|
|
});
|
|
```
|
|
|
|
In this case this is not working as there isn't any instance and the function is Static
|
|
|
|
### Static Function
|
|
|
|
If the function is static, you could just call it:
|
|
|
|
```javascript
|
|
//hook2.js
|
|
Java.perform(function () {
|
|
console.log("[ * ] Starting PIN Brute-force, please wait...")
|
|
var PinUtil = Java.use("infosecadventures.fridademo.utils.PinUtil");
|
|
|
|
for(var i=1000; i < 9999; i++)
|
|
{
|
|
if(PinUtil.checkPin(i+"") == true){
|
|
console.log("[ + ] Found correct PIN: " + i);
|
|
}
|
|
}
|
|
});
|
|
```
|
|
|
|
## Hook 3 - Retrieving arguments and return value
|
|
|
|
You could hook a function and make it **print** the value of the **passed arguments** and the value of the **return value:**
|
|
|
|
```javascript
|
|
//hook3.js
|
|
Java.perform(function() {
|
|
console.log("[ * ] Starting implementation override...")
|
|
|
|
var EncryptionUtil = Java.use("infosecadventures.fridademo.utils.EncryptionUtil");
|
|
EncryptionUtil.encrypt.implementation = function(key, value){
|
|
console.log("Key: " + key);
|
|
console.log("Value: " + value);
|
|
var encrypted_ret = this.encrypt(key, value); //Call the original function
|
|
console.log("Encrypted value: " + encrypted_ret);
|
|
return encrypted_ret;
|
|
}
|
|
});
|
|
```
|
|
|
|
## Important
|
|
|
|
In this tutorial you have hooked methods using the name of the mathod and _.implementation_. But if there were **more than one method** with the same name, you will need to **specify the method** that you want to hook **indicating the type of the arguments**.
|
|
|
|
You can see that in [the next tutorial](frida-tutorial-2.md).
|
|
|