Accessibility Service Utilization Rates in Android Applications Shared on Twitter

Abstract

The number of malware detected has been increasing annually, and 4.12% of malware reported in 2018 attacked Android phones. Therefore, preventing attacks by Android malware is critically important. Several previous studies have investigated the percentage of apps that utilize accessibility services and are distributed from Google Play, that have been reportedly used by Android malware. However, the Social Networking Services (SNSs) that are used to spread malware have distributed apps not only from Google Play but also from other sources. Therefore, apps distributed from within and outside of Google Play must be investigated to capture malware trends. In this study, we collected apps shared on Twitter in 2018, which is a representative SNS, and created a Twitter shared apps dataset. The dataset consists of 32,068 apps downloaded from the websites of URLs collected on Twitter. We clarified the proportion of apps that contained malware and proportion of apps utilizing accessibility services. We found that both, the percentage of malware and percentage of total apps using accessibility services have been increasing. Notably, the percentages of malware and un-suspicious apps using accessibility services were quite similar. Therefore, this problem cannot be solved by automatically blocking all apps that use accessibility services. Hence, specific countermeasures against malware using accessibility services will be increasingly important for online security in the future.