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Objection Tutorial ​

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Introduction ​

objection - Runtime Mobile Exploration

Objection is a runtime mobile exploration toolkit, powered by Frida. 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 Download
app-release.zip

Or from its original repository (download app-release.apk)

Installation ​

bash
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:

bash
frida-ps -Uai
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.

bash
env

Frida Information ​

bash
frida

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 ​

bash
android hooking list activities

bash
android hooking list services
android hooking list receivers

Frida will launch an error if none is found

Getting current activity ​

bash
android hooking get current_activity

Search Classes ​

Lets start looking for classes inside our application

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

Search Methods of a class ​

Now lets extract the methods inside the class MainActivity:

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

List declared Methods of a class with their parameters ​

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

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

List classes ​

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

bash
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 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):

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

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.

bash
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.

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:

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

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>

Keystore/Intents ​

You can play with the keystore and intents using:

bash
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 ​

bash
memory list modules

At the bottom os the list you can see frida:

Lets checks what is frida exporting:

Search/Write ​

You can alse search and write inside memory with objection:

bash
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 ​

bash
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.

Bug bounty tip: sign up for Intigriti, a premium bug bounty platform created by hackers, for hackers! Join us at https://go.intigriti.com/hacktricks today, and start earning bounties up to $100,000!

⛓️ External Link
https://go.intigriti.com/hacktricks
Learn AWS hacking from zero to hero with htARTE (HackTricks AWS Red Team Expert)!

Other ways to support HackTricks: