hacktricks/mobile-apps-pentesting/android-app-pentesting/frida-tutorial/objection-tutorial.md

# Objection Tutorial

## **Introduction**

[![objection](https://github.com/sensepost/objection/raw/master/images/objection.png)](https://github.com/sensepost/objection)

**objection - Runtime Mobile Exploration**

`objection` is a runtime mobile exploration toolkit, powered by [Frida](https://www.frida.re). It was built with the aim of helping assess mobile applications and their security posture without the need for a jailbroken or rooted mobile device.

**Note:** This is not some form of jailbreak / root bypass. By using `objection`, you are still limited by all of the restrictions imposed by the applicable sandbox you are facing.

### Resume

The **goal** of **objection** is let the user call the **main actions that offers Frida**. **Otherwise**, the user will need to create a **single script for every application** that he wants to test.

## Tutorial

For this tutorial I am going to use the APK that you can download here:

{% file src="../../../.gitbook/assets/app-release.zip" %}

Or from its [original repository ](https://github.com/asvid/FridaApp)(download app-release.apk)

### Installation

```
pip3 install objection
```

### Connection

Make a **regular ADB conection** and **start** the **frida** server in the device (and check that frida is working in both the client and the server).

If you are using a **rooted device** it is needed to select the application that you want to test inside the _**--gadget**_ option. in this case:

```
objection --gadget asvid.github.io.fridaapp explore
```

### Basic Actions

Not all possible commands of objections are going to be listed in this tutorial, only the ones that I have found more useful.

#### Environment

Some interesting information (like passwords or paths) could be find inside the environment.

```
env
```

![](<../../../.gitbook/assets/image (64).png>)

#### Frida Information

```
frida
```

![](<../../../.gitbook/assets/image (65).png>)

#### Upload/Download

```bash
file download <remote path> [<local path>]
file upload <local path> [<remote path>]
```

#### Import frida script

```bash
import <local path frida-script>
```

#### SSLPinning

```bash
android sslpinning disable #Attempts to disable SSL Pinning on Android devices.
```

#### Root detection

```bash
android root disable  #Attempts to disable root detection on Android devices.
android root simulate #Attempts to simulate a rooted Android environment.
```

#### Exec Command

```bash
android shell_exec whoami
```

#### Screenshots

```bash
android ui screenshot /tmp/screenshot
android ui FLAG_SECURE false  #This may enable you to take screenshots using the hardware keys
```

### Static analysis made Dynamic

In a real application we should know all of the information discovered in this part before using objection thanks to **static analysis**. Anyway, this way maybe you can see **something new** as here you will only have a complete list of classes, methods and exported objects.

This is also usefull if somehow you are **unable to get some readable source code** of the app.

#### List activities, receivers and services

```
android hooking list activities
```

![](<../../../.gitbook/assets/image (78).png>)

```
android hooking list services
android hooking list receivers
```

Frida will launch an error if none is found

#### Getting current activity

```
android hooking get current_activity
```

![](<../../../.gitbook/assets/image (73).png>)

#### Search Classes

Lets start looking for classes inside our application

```
android hooking search classes asvid.github.io.fridaapp
```

![](<../../../.gitbook/assets/image (69).png>)

#### Search Methods of a class

Now lets extract the methods inside the class _MainActivity:_

```
android hooking search methods asvid.github.io.fridaapp MainActivity
```

![](<../../../.gitbook/assets/image (70).png>)

#### List declared Methods of a class with their parameters

Lets figure out wich parameters does the methods of the class need:

```
android hooking list class_methods asvid.github.io.fridaapp.MainActivity
```

![](<../../../.gitbook/assets/image (79).png>)

#### List classes

You could also list all the classes that were loaded inside the current applicatoin:

```
android hooking list classes #List all loaded classes, As the target application gets usedmore, this command will return more classes.
```

This is very useful if you want to **hook the method of a class and you only know the name of the class**. You coul use this function to **search which module owns the class** and then hook its method.

### Hooking being easy

#### Hooking (watching) a method

From the [source code](https://github.com/asvid/FridaApp/blob/master/app/src/main/java/asvid/github/io/fridaapp/MainActivity.kt) of the application we know that the **function** _**sum()**_ **from** _**MainActivity**_ is being run **every second**. Lets try to **dump all possible information** each time the function is called (arguments, return value and backtrace):

```
android hooking watch class_method asvid.github.io.fridaapp.MainActivity.sum --dump-args --dump-backtrace --dump-return
```

![](<../../../.gitbook/assets/image (71).png>)

#### Hooking (watching) an entire class

Actually I find all the methods of the class MainActivity really interesting, lets **hook them all**. Be careful, this could **crash** an application.

```
android hooking watch class asvid.github.io.fridaapp.MainActivity --dump-args --dump-return
```

If you play with the application while the class is hooked you will see when **each function is being called**, its **arguments** and the **return** value.

![](<../../../.gitbook/assets/image (72).png>)

#### Changing boolean return value of a function

From the source code you can see that the function _checkPin_ gets a _String_ as argument and returns a _boolean_. Lets make the function **always return true**:

![](<../../../.gitbook/assets/image (74).png>)

Now, If you write anything in the text box for the PIN code you will see tat anything is valid:

![](<../../../.gitbook/assets/image (77).png>)

### Class instances

Search for and print **live instances of a specific Java class**, specified by a fully qualified class name. Out is the result of an attempt at getting a string value for a discovered objection which would typically **contain property values for the object**.

```
android heap print_instances <class>
```

![](<../../../.gitbook/assets/image (80).png>)

### Keystore/Intents

You can play with the keystore and intents using:

```
android keystore list
android intents launch_activity
android intent launch_service
```

### Memory

#### Dump

```bash
memory dump all <local destination> #Dump all memory
memory dump from_base <base_address> <size_to_dump> <local_destination> #Dump a part
```

#### List

```
memory list modules
```

![](<../../../.gitbook/assets/image (66).png>)

At the bottom os the list you can see frida:

![](<../../../.gitbook/assets/image (67).png>)

Lets checks what is frida exporting:

![](<../../../.gitbook/assets/image (68).png>)

#### Search/Write

You can alse search and write inside memory with objection:

```
memory search "<pattern eg: 41 41 41 ?? 41>" (--string) (--offsets-only)
memory write "<address>" "<pattern eg: 41 41 41 41>" (--string)
```

### SQLite

You cals can use the command `sqlite` to interact with sqlite databases.

### Exit

```
exit
```

## What I miss in Objection

* The hooking methods sometimes crashes the application (this is also because of Frida).
* You can't use the instaces of the classes to call functions of the instance. And you can't create new instances of classes and use them to call functions.
* There isn't a shortcut (like the one for sslpinnin) to hook all the common crypto methods being used by the application to see cyphered text, plain text, keys, IVs and algorithms used.