The app was developed by Geohot
It supports Verizon ,AT&T Galaxy S3 , S5 , S4Active, S4 and nexus 5 with (4.4.2-- 4.3 firmware for all build versions)
1- Download app from attachment
2- install it ( it will tell you the app passes Google's security click Accept) Don't scare it wil not harm your Device.
3- click ( make it Ra1n)
Notice: If your phone rebooted that means the root Failed !!
Pics from my rooted SCH-i535 kitkat 4.4.2 in attachments
Don't forget to install Supersu to disable Knox