Intercepting Android App Traffic

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🌐 Resources 🔗

• Genymotion

• Frida

• OWASP SSL Certificate and Public Key Pinning

• Extra video - Getting Started with Android App Testing with Genymotion - InsiderPhD

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Bypass certificate pinning with Frida

I've used my KaliVM and this instructions to follow IppSec's video and get everything working as he described.

🔗 Intercepting Android App Traffic with BurpSuite - by IppSec

Video Timeline

00:00 - Introduction, talking about RouterSpace and why we can't just do what we did in that video
01:25 - Installing Genymotion, Virtual Box, and ADB; while talking about why I don't use Android Studio/AVD. Simply because genymotion just works.
02:05 - Make sure you upgrade your memory, processors, and enable Virtualization in your VM Settings!
02:30 - Running Genymotion and starting a Pixel 3 XL
03:37 - Converting BurpSuites Certificate to PEM Format with openssl x509 -inform der -in [name of cert] -out burp.pem
04:20 - Renaming the certificate to 9a5ba575.0, and showing how we got that name
06:00 - Starting the device and showing the certificate authorities
07:00 - Copying the certificate to /system/etc/security/cacerts/, and showing how to remount to rw
08:10 - Showing how to set the proxy through both the GUI and via ADB
09:50 - Installing GAPPS
10:30 - Showing how to unset the proxy from ADB
11:00 - Creating an alias to set and unset the proxy via adb
12:00 - Opening the google play store and logging in and install Wayzn to see if we can intercept traffic
15:20 - Showing we intercepted traffic from Wayzn, then installing Instagram
16:50 - Attempting to login to instagram and getting an error message
17:20 - Setting up Frida both on our computer and android device
19:20 - Showing Frida is working, getting ps output from the android device
19:55 - Downloading the instragram ssl pinning bypass script
21:20 - Using frida to start instagram and loading the script to bypass the SSL Checking
22:15 - Setting the proxy and showing us intercept instagram traffic

sudo apt install -y virtualbox adb
sudo wget https://dl.genymotion.com/releases/genymotion-3.5.1/genymotion-3.5.1-linux_x64.bin -O /tmp/genymotion.bin

sudo chmod +x genymotion.bin
sudo ./genymotion.bin

cd /opt/genymobile/genymotion
./genymotion

• Open Genymotion Settings and setup Hypervisor to Virtualbox

• Install a new Google Pixel 3 XL device

• Run Burpsuite and copy its certificate

cd
curl localhost:8080/cert -o cert.der
sudo mv cert.der /usr/share/ca-certificates/BurpSuiteCA.der

openssl x509 -inform der -in /usr/share/ca-certificates/BurpSuiteCA.der -out burp.pem
openssl x509 -inform PEM -subject_hash_old -in burp.pem
mv burp.pem 9a5ba575.0 	# Output from above

• Copy cert to device

adb devices -l
adb shell
su
mount -o remount,rw /
exit
exit

adb push 9a5ba575.0 /system/etc/security/cacerts/

• To start capturing traffic with BurpSuite, set the proxy listener to All interfaces

• Set the proxy usage on the device, with the KaliVM IP

adb shell settings put global http_proxy 192.168.31.128:8080

# Create an alias for set and unset proxy
alias adb_set_proxy="adb shell settings put global http_proxy $(ip -o -4 addr show eth1 | awk '{print $4}' | sed 's/\/.*//g'):8080"

alias adb_unset_proxy="adb shell settings put global http_proxy :0"

• From Genymotion, click OpenGAPPS to install Gapps on the device and restart the device.

# Disable proxy
adb_unset_proxy

• Run Play Store on the device and install apps

  • e.g. - Wayzn, Instagram - in this case

• Try to set the proxy, turn BurpSuite intercept on and login into the Wayzn app

adb_set_proxy

• Open Instagram and try to login. Unable to log in with proxy set.

• Unsetting the proxy, Instagram error changes.

  • Instagram prevents from intercepting the traffic

• Install Frida

  • 🔗 Follow Frida Android

# On KaliVM
pipx install frida-tools                                   

# On device
adb shell
uname -a
	Linux localhost 5.10.101-genymotion+-ab74 #1 SMP PREEMPT Thu Dec 1 14:03:02 UTC 2022 x86_64

# x86_64 -  Download frida-server-16.1.1-android-x86_64.xz
exit
wget https://github.com/frida/frida/releases/download/16.1.1/frida-server-16.1.1-android-x86_64.xz

7z x frida-server-16.1.1-android-x86_64.xz
mv frida-server-16.1.1-android-x86_64 frida-server

adb push frida-server /data/local/tmp/
adb shell "chmod 755 /data/local/tmp/frida-server"
adb shell "/data/local/tmp/frida-server &"

• Check Frida is working

frida-ps -U		# This is device output
     PID  Name
    ----  -------------------------------------------------------------
    5446  Google Play Store
    6085  Instagram
    1960  Phone
    5249  Wayzn
     473  adbd
    1268  android.ext.services
    [...]

• Download the Instagram SSL Pinning Bypass script 22:15 - Setting the proxy and showing us intercept instagram traffic

sudo mkdir -p /opt/android/instagram
cd /opt/android/instagram

sudo wget https://raw.githubusercontent.com/Eltion/Instagram-SSL-Pinning-Bypass/main/instagram-ssl-pinning-bypass.js

• Force stop Instagram app from App info

• Use Frida to start Instagram and load the script to bypass the SSL Checking

adb_set_proxy
frida -U -l ./instagram-ssl-pinning-bypass.js -f com.instagram.android

• Show Instagram intercepted traffic in BurpSuite

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