HOW TO ROOT SAMSUNG GALAXY S3 i9300 on Android 4.3

Samsung Galaxy S3
Guide to root Galaxy S3 on I9300XXUGMK6 Android 4.3 Jelly Bean.

ROOT 4.3 Samsung S3

Earlier this month, a new stock firmware build I9300XXUGMK6 based on Android 4.3 Jelly Bean was rolled out by Samsung for the international version of Galaxy S3.

Firmware details
Model: GT-I9300
Country: Open Europe
Version: Android 4.3 Jelly Bean
Changelist: 2168382
Build date: 28 November
Product code: OXA

The I9300XXUGMK6 build is for users across the European region. It carries several new changes and improvements such as Galaxy Gear support, TRIM support, Samsung Wallet, new Samsung keyboard, new lockscreen, new S-voice, new Camera mode and Daydream, reports Sammobile.
Galaxy S3 users who have updated their devices to I9300XXUGMK6 Android 4.3 and wish to root the same may follow our step-by-step guide. This method uses CF-Root file released by well known XDA developer, Chainfire.

1) Install USB Driver for Samsung Galaxy S3 to connect the Android device with the computer.
2) Enable USB Debugging Mode on phone to connect it with computer and use Android SDK with it. [Navigate to Settings>> Developer Options to enable USB Debugging Mode.]
3) As the tutorial might wipe out all data of the phone, create a backup. If the device is having any custom recoveries such as CWM/TWRP then backup data using the recovery.
4) If the Android phone powers off due to lack of battery while the installation process, it could damage the device. Therefore, the Galaxy S3 should have charge above 80% battery charge.
5) Rooting the phone will void its manufacturer's warranty. Users can reclaim the warranty back by unrooting the same. Click here for a guide to unroot Samsung Galaxy S3 to stock official firmware and reclaim warranty.
6) The CF Root package works only on Samsung Galaxy S3 GT-I9300. As applying this to any other variant might brick the device, verify the model number of Galaxy S3 by navigating to Settings>> About device>> Model number.

How to root Galaxy S3 on I9300XXUGMK6 Android 4.3 Jelly Bean
Step-1: Download the CF-Root file for Galaxy S3 to the computer and extract the downloaded zip file to get a file with .tar extension
File name: 
Step-2: Download Odin v3.07 and extract the Odin zip
Step-3: Switch off the Galaxy S3. Place the phone into Download Mode by pressing and holding Volume Down, Home and Power buttons together until the construction Android robot and a triangle appears on the screen. Press the Power button again to confirm to enter into Download Mode
Step-4: Run Odin on computer
Step-5:  Connect the Galaxy S3 to computer while it is in Download Mode. Wait for some time until Odin detects the device. When the phone is connected successfully an Added message will appear under Odin. Also, the ID: COM box in Odin will turn blue with the COM port number, indicating successful connection
Note: If the Added message does not come then try another USB port, try the one located at the back side of the computer. If Odin still fails to recognise the device then re-install USB driver.
Step-6: Click PDA in Odin and select the CF-Root-SGS3-v6.4.tar file
Step-7: Verify Auto Reboot and F. Reset Time checkboxes are selected in Odin window
 Step-8: Click the Start button in Odin to begin the installation which would take about a few minutes
Step-9: When the installation process is completed, the phone will restart automatically. After the home screen appears, disconnect the phone from the computer
The Galaxy S3 should now be successfully rooted on I9300XXUGMK6 Android 4.3 Jelly Bean firmware. Open the app drawer of the phone and look for Superuser app. To ensure the root method is installed and working properly, install Root Checker app, available to download from Google Play Store.