The infection begins when a user downloads and installs a Gooligan-infected app on a vulnerable Android device. Our research team has found infected apps on third-party app stores, but they could also be downloaded by Android users directly by tapping malicious links in phishing attack messages.  After an infected app is installed, it sends data about the device to the campaign’s Command and Control (C&C) server.
Gooligan then downloads a rootkit from the C&C server that takes advantage of multiple Android 4 and 5 exploits including the well-known VROOT (CVE-2013-6282) and Towelroot (CVE-2014-3153). These exploits still plague many devices today because security patches that fix them may not be available for some versions of Android, or the patches were never installed by the user. If rooting is successful, the attacker has full control of the device and can execute privileged commands remotely.
After achieving root access, Gooligan downloads a new, malicious module from the C&C server and installs it on the infected device. This module injects code into running Google Play or GMS (Google Mobile Services) to mimic user behavior so Gooligan can avoid detection, a technique first seen with the mobile malware HummingBad.
The module allows Gooligan to:
Steal a user’s Google email account and authentication token information
Install apps from Google Play and rate them to raise their reputation
Install adware to generate revenue
Ad servers, which don’t know whether an app using its service is malicious or not, send Gooligan the names of the apps to download from Google Play. After an app is installed, the ad service pays the attacker. Then the malware leaves a positive review and a high rating on Google Play using content it receives from the C&C server.