Thanks to KNOX, rooting Samsung devices released in the last one year or so has become an incredibly tough task. While rooting them is possible, it will end up triggering the KNOX hardware switch, which effectively voids the warranty of the device. Since this is a hardware level switch, there is no way to reverse this process or fix it later on.
Worse, carriers in the United States lock down the bootloader on their devices, which makes it near impossible for developers to unlock the device.
Developers usually try to find an exploit via which they can gain root access on such Samsung devices, but with time, Android OEMs have patched most of them and finding new ones is an incredibly tough job. The AT&T and Verizon variant of the Galaxy S5 are a perfect example for this case and have a staggering $18,000+ bounty on offer for anyone who manages to root the handset.
Now, it looks like geohot (known for unlocking the iPhone) has managed to gain root access on not only the carrier variants of the Galaxy S5 but also the Note 3, Nexus 5 and possibly all other Android devices with a kernel build date of below June 3 via his ‘towel root’ exploit.
The root exploit is scheduled to be released to the public at 10AM PDT on 15/6/14. So, make sure to check back this XDA thread or this website if you want to gain root access on your Galaxy S5, Note 3 or any other Android device by simply installing an APK.
Once this root exploit is released, geohot will be entitled to receive a bounty of $18,000 from XDA members for rooting the handset.
Update: The root exploit is now live!