Android is becoming hot target for new malwares due to its open source adaptability and less control over new apps like apple. Realizing this threat Android 4.2 has been loaded with new security features against malwares. This version, released in 2012 includes a malware scanner which works in coordination with Google play. It has the ability to scan the third party apps.
If you try to install an app from any source other than Google play for first time you are given an option to scan that app by Google for Harmful behavior. You are also given an option in phones security settings to turn this service on or off as per your need. This warning would come even if you get an app from a third party reputed markets like Amazon app store etc.
If the malware scanner finds something to raise doubt but have no history of any harmful effect, it will raise red flag about it and will give an option to decide about the future course of action. You may still proceed on the installation of app if you trust the source and understand the possible impact of such app. However, if the app is known to be dangerous then the system may prevent you from installing it.
Many of the android app malwares send sms from your smartphones without your knowledge at numbers which can cost you money. Android 4.2 has plugged hole for such kind of malwares. It alerts the user whenever any app tries to send automatic sms from your smartphone to a fee collecting numbers (Numbers which automatically bill your telecom service providers when they receive a message). Upon such identification, it will give user an option to accept or reject such outgoing sms. By rejecting those sms you are saved of the unnecessary cost which could have come your way from such malwares.
There is a debate going on whether this security feature is enough or not keeping in view of new kind of malwares getting invented every day. Few researches claim that such security features give nothing more than 15% protection but this is a step in the right direction. Nothing gives 100% protection but using such features definitely gives you one round of protection. With more data becoming available on the effect and DNA of malwares such security measures are only going to become stronger.