Malware Risk on Mobile Platforms appears to be increasing. A flood of scammy apps that are difficult for Google to detect are available for download for several days before being removed. Android phones are more susceptible than iPhones because their app stores are more open. Criminals generally take genuine apps, insert the malicious software, and sell them in the app store for free or at a discount. Android has a larger and larger percentage of the mobile operating system market share, Android is starting to become more attractive to programmers and hackers alike.
Source: https://thehackernews.com/2013/08/Android-hacking-apps-download-malware-tool.html