Mobile phone users should carefully ensure they download the Pokemon-Go from official sites only.  Due to it’s popularity, fake versions are now appearing on alternate malicious sites, as noted below:  

https://www.proofpoint.com/us/threat-insight/post/droidjack-uses-side-load-backdoored-pokemon-go-android-app

Pokemon GO is the first Pokemon game sanctioned by Nintendo for iOS and Android devices. The augmented reality game was first released in Australia and New Zealand on July 4th and users in other regions quickly clamored for versions for their devices. It was released on July 6th in the US, but the rest of the world will remain tempted to find a copy outside legitimate channels. To that end, a number of publications have provided tutorials for “side-loading” the application on Android. However, as with any apps installed outside of official app stores, users may get more than they bargained for.

In this case, Proofpoint researchers discovered an infected Android version of the newly released mobile game Pokemon GO. This specific APK was modified to include the malicious remote access tool (RAT) called DroidJack (also known as SandroRAT), which would virtually give an attacker full control over a victim’s phone. The DroidJack RAT has been described in the past, including by Symantec and Kaspersky. Although we have not observed this malicious APK in the wild, it was uploaded to a malicious file repository service at 09:19:27 UTC on July 7, 2016, less than 72 hours after the game was officially released in New Zealand and Australia.

ConclusionInstalling apps from third-party sources, other than officially vetted and sanctioned corporate app stores, is never advisable. Official and enterprise app stores have procedures and algorithms for vetting the security of mobile applications, while side-loading apps from other, often questionable sources, exposes users and their mobile devices to a variety of malware. As in the case of the compromised Pokemon GO APK we analyzed, the potential exists for attackers to completely compromise a mobile device. If that device is brought onto a corporate network, networked resources are also at risk.