ModZoo: A Large-Scale Study of Modded Android Apps and their Markets

We present the results of the first large-scale study into Android markets that offer modified or modded apps: apps whose features and functionality have been altered by a third-party. We analyse over 146k (thousand) apps obtained from 13 of the most popular modded app markets. Around 90 are altered in some way when compared to the official counterparts on Google Play. Modifications include games cheats, such as infinite coins or lives; mainstream apps with premium features provided for free; and apps with modified advertising identifiers or excluded ads. We find the original app developers lose significant potential revenue due to: the provision of paid for apps for free (around 5 premium features that require payment in the official app; and modified advertising identifiers. While some modded apps have all trackers and ads removed (3 risky for the user than the official version: modded apps are ten times more likely to be marked as malicious and often request additional permissions.