- Antivirus: This is the first thing any android user should install. Most anti virus softwares detect malwares and even security flaws in the Settings of android devices. Getting an anti virus won't hurt in anyway; you can choose to get it free if you just use your device for normal use but you should be thinking of dropping a few dollars in if you use your device for commercial purposes ( this is to say you would need to upgrade to pro for more features). Some anti virus apps for android are; Avast, AVG, Kaspersky, Bitdefender, McAfee, Norton and so on.
- Download apps from trusted sources: This I don't really need to say. It is very obvious that downloading from untrusted sources can cause so many problems in the long run. If you want to download apps but you can't or do not want to download them from the playstore, then you can go to Amazon, Samsung's store, or another major manufacturer or carrier. These sources always scan all apps placed there though some apps bypass the checks.
- Never leave "Unknown sources" enabled: Unknown sources should only be enabled when you need to installs apps manually outside the Playstore and mostly we do this when we trust the alternate source. Unfortunately, some websites can capitalize on this feature and install some malware infested apps on your device without your knowledge. To prevent this, go to Settings > Security > Unknown sources.
- Avoid pirated apps: This is quite obvious. Why would someone buy an app and wanna give it out for free? Well, some do it with a free heart but some also embed some codes in them before giving them out. This helps them get an easier asses to your device. To put in simpler terms, you're actually giving them the key to your phone instead of you giving them tough time breaking into your phone.
- Update your phone's software regularly: Recently, google and other major Android device manufacturers have decided to roll out security updates regularly to Android devices. This is to minimize the security flaws already encountered in Android. For you to be able to keep receiving updates, set your updates to automatic and this will help to secure your device more. In order to do this, go to Settings > About device > Software update and check the Auto update box.
- Security settings: Android comes with its own security features in the operating system that can prevent malicious attacks. Devices running Android 2.2 or higher have access to Google's malware scanner. Prior to installing an application you downloaded outside of the Play store, Google will scan the app and warn you of any potential threats.
This feature is factory enabled and can be accessed in the Google Settings app in your device's app drawer. Alternatively, devices running Android 4.2 or higher can access the feature by going to Settings > Security > Verify apps. - Read your apps' permission: Before you install any app be it from the Playstore or any other source, make sure you do what more than 90% of all Android users fail to do; read the permissions the app is asking. Sometimes apps can ask for very weird permissions. An example is a camera app asking for your location. Whoa! all you want to do is take a picture and not put yourself on google map. Some of the permissions they take aid some developers get easy access to your device and do anything they want with it.
These are the few ways you can protect your Android device against external attacks.
Hope these will help you protect your Android device better. If you have any questions or suggestion, don't forget to drop it in the comment box.