A really bad exploit in the Android OS enables the installation of malware called QuadRooter. Google is working to push security updates, and promises to have an update by September. If your manufacturer or wireless provider is slow to push out updates, then you may be vulnerable for quite some time, especially if you have an old phone. If you're looking to get a new phone, make sure you're getting it from a company that's offering monthly updates.
Leo says Android users should also limit their app downloads to the Google Play store. Google is actively screening programs in an effort to prevent malicious software from being installed.