Android has been having a massive shift toward tighter security lately, and for good reason. Over the years, tons and tons of exploits and malware have popped up to try and get at users of Google's mobile OS. Droiddream, Heartbleed and Stagefright, among others, tried to either gain control of devices or glean user details. Security patches ended up eradicating all of these bugs as of Android 5.1.1 Lollipop, but not everybody is up to date. Additionally, with Android devices being on the easy side to reset if stolen, it's essential to have a lockscreen passcode of some sort, as well as a code needed to boot up an Android device. According to some frankly jaw-dropping statistics pulled by Duo Analytics, the amount of Android devices in the wild that are vulnerable in some form or another is pretty high.
For starters, Android versions 4.0 Ice Cream Sandwich and below are not only ancient, but also incredibly vulnerable. The issue is that a full 32 percent of Androids out there are running those old versions. As essential as a screen lock of some sort is to secure your device if it should be lost or stolen, about one out of every three users don't have them set. This means anybody could just pick up their phone, reset it, pop in their own SIM card and be on their merry way with a new device. Additionally, although Android has encryption by default from Android 5.0 Lollipop and onward, only one of every ten users have a passcode to boot up their device. Combine this with the fact that one in twenty Android devices are rooted, which makes them more feature-rich but also more vulnerable, and you have a recipe for disaster. A rooted device with a custom recovery can be reset even if it's encrypted and has a boot passcode, in most cases. A rooted device running Android 4.0 and earlier is, of course, far more vulnerable to exploits and they can do tons more damage than they otherwise would have.
This may sound terrifying, but there are some fairly simple steps anybody can take to secure their device to the maximum it's capable of, even if the device is from the early days of Android. For starters, update as high as you possibly can. Most phones these days will have Android 5.1.1 Lollipop, but if your phone is older, official updates may have stopped a while back. With some devices, official updates may stop while the custom ROM scene keeps the device up to date. The Samsung Galaxy S3, for example, stopped at Android 4.1.2 Jelly Bean for some carriers, but can be updated to Android 5.1.1 Lollipop via CyanogenMod. Naturally, of course, this comes with the added risks of being rooted, so use caution. Be sure to use encryption and a passcode if they're available on your device. Should your device ever go missing, you can turn to Android Device Manger to find it, so long as it hasn't been reset.