Android along with every other operating system has viruses. recently defcon 2013 a researcher discovered that they can modify the android APK and still keep the signature of the package to make it look authentic.
This can be a major problem for Android as any app that you use can look authentic but have virus attached to it. This virus can attach it self to other APKs and infect them, causing your device to be compromised and your personal information stolen. The vulnerability, Android security bug 8219321, lets attackers modify Android apps into Trojan apps without breaking their APK signature.
This is a serious vulnerability that has been recently fixed in the android OS. You will want to make sure that you update your android operating system so that you can help protect your self. This vulnerability has been scanned for by Google on their Play Store for some time since it was published. Though this does not protect you from it if you get your APKs from non Play Store sources.
So if you have your android phone keep it updated to the latest so that you can get patched. Also hopefully you have an provider that will push the patch out. I use Cyanogenmod which requires version 10.1.2 to have the patch. If you do not have that version on your device then you will want to upgrade now to help prevent your device from being infected.
Also this becomes very important if the app is a root app.
Thanks for Reading,
-Local Tech Repair Admin