There are many reports of fraudulent applications that offer so called “security scans” of your device or of the network you are connected to but instead do nothing.
Many of the concerns regarding Android malware are most of the times exaggerated. Google has releases it Android State of the Union and it has found out that malware installations were down by half of what they were a year before their tracked period. Furthermore if an Android user only installed applications from the Play Store then the chances of him/her being infected are only 0.15%.
The conclusion here is that we should stick to installing applications only from trusted sources like Google’s play store or Amazon’s app store. If one seeks enhanced protection for their device then only use a security solution from a trusted and known developer, at least until Google manages to remove most of the fraudulent(fake) apps from its store.