Android (4.4+): Rooting your Android phone or tablet involves connecting it to a PC, using ADB, and several other steps. But developer geohot has now released Towelroot, a new tool that makes rooting many Android devices as simple as installing an app and running it.
Before you continue, there are a few things you should know. First, rooting your device potentially voids your warranty. Second, this tool only works on phones running Android KitKat. Third, it won't work with Motorola or HTC phones.
Installing and running it is easy. Go to Settings -> Security and enable installing apps from unknown sources. Then head to Towelroot.com, download and install the APK, and run it. It takes about a minute for your device to be rooted and reboot. Check whether it worked using Root Checker.
Originally, this hack was made to root the Samsung Galaxy S5, but users are reporting success with several other models. We asked several friends to try it out and used a few of our own unrooted devices and it worked with the Sony Xperia Z1 Compact, Samsung Galaxy Note 3, Google Nexus 5, Google Nexus 7 (2013) and the LG G2. It did not work with the HTC One M8, Moto E, Moto G and HTC One Mini.
As WonderHowTo notes, Towelroot gives any app root access if it's asked. This could be a major security risk, so you should install a root management app like SuperSU. Head to the WonderHowTo link below for more details on this.
You can find out more about Towelroot and direct questions to the community over at the official thread on XDA Developers Forum.