.3uTools can downgrade the following devices: iPhone 3GS without SHSH file backup can be downgraded to iOS4.1 using 3uTools. IPhone 4 with SHSH file backups can be downgraded to any compatible firmware using 3uTools. May 08, 2018 First, you will need to install 3utools for windows. Erase All Data: Erase any Data and Settings without Upgrading iOS with 3uTools download: 3uTools iOS jailbreak & flash tool. Download and install 3utools, connect your device to the computer and let the 3u software recognize the device, accept and thrust computer and device. Jan 23, 2018  Step 1 Right click 3uTools, then then click “Open File Location”. Step 2 Find out the file named “setting.cfg” and open it to edit. Step 3 Add “xd=true” below “Network” as the following picture. Step 4 You can save this new “setting.cfg” at any folder. Then replace this edited file to the folder of 3uTools. Above is a guide on how to convert 3uTools language into Vietnamese, using 3uTools or any software in Vietnamese will also be more effective when many people do not understand some English words or do not know English, is Default language of the software. Download the iOS firmware you want to downgrade on If you saved SHSH2 file saved on 3uTools server: If you never uninstall 3uTools, you could find the SHSH2 files in 3uTools’ cache folder. Downgrade with SHSH2 using 3uTools. Step 1 Connect your iDevice to 3uTools and go to Flash & JB.

Reverse engineering the commonly used 3utools software to make it more open and learn about it.

Why

3utools is amazingly great software for managing iOS devices.
Not only does it show you a lot information about hardware integrity of your devices, it also helps you fix problems and jailbreak them.
3utools is not opensource but has an API for most of their functionality.
For the freedom of development I wanted to see if this API can be reused by developers as that would make the life of security researchers easier.

The Research

3utools has the ability to specify a proxy in the settings.
Since the traffic of 3utools is encrypted via TLS, I am using fiddler with its own CA certificate.
After launching fiddler I simply set the proxy server in the settings to be localhost with port 8888, which is what fiddler runs on.
Burpsuite is also possible the same way which is amazing for debugging API calls and reproducing / interacting with API calls.

First 0-day vulnerability reported

Without even using any research tools like burpsuite and fiddler I expected that most of the content loaded in 3utools is actually just a webpage with a lot of javascript, this due to the delays in rendering certain userinterface graphics because that could mean and turned out to be loaded over the network.

3utools Will Not Connect To Firmware Server Mac

3utools was vulnerable to a low-risk cross site scripting vulnerability which I found by simply entering '<script>alert(1)</script>' in almost any of the input fields a user could access in the software.With that I also found the domain where their UI is located at.

Without further interruption or waiting, I immediately reported the vulnerability to 3utools and it got patched the same day.
However, I did not get any bounty. After all 3utools is free software anyway.

3utools Will Not Connect To Firmware Server Windows 7

Amazing infrastructure

3utools seems to have amazing infrastructure.
They have a persitant file storage server where they store almost any iOS firmware related files, such as developer dmgs and jailbreaks.
This makes their service faster than Apple's and able to download files even when Apple's servers are down.
What is where and where is what is yet to be found out, but at least I discovered that when clicking the 'view screen' button you can see that the corresponding developer dmg image is downloaded for your device and mounted.
Probably because they use the 'screenshotr' xpc service to get the live screen.
For developers and researchers this means it is amazingly easy to quickly download the developer dmg from their servers as they are all named logically.

Aside the filestorage they also have a REST json API with one can retrieve information about firmware.
One can ask the API to only give jailbreakable or jailbreakable and signed firmware or just any firmware for specific devices and OS versions.
Great feature if you ask me, again for developers and researchers a good way to automate their work a few more.

3utools Will Not Connect To Firmware Server Password

NOTE FOR DEVELOPERS: You can see the full documentation being developed when clicking the 'wiki' here on GitHub.

TLDR:Reverse engineering 3utools pays off and the first vulnerability has been fixed.
Developers and researchers benefit from 3utools rest API and filestorage.