Google's Android platform has become the most popular mobile operating system both among consumers and malware writers, and the company earlier this year introduced the Bouncer system to look for malicious apps in the Google Play market. Bouncer, which checks for malicious apps and known malware, is a good first step, but as new work from researchers Jon Oberheide and Charlie Miller shows, it can be bypassed quite easily and in ways that will be difficult for Google to address in the long term. Oberheide and Miller, both well-known for their work on mobile security, went into their research without much detailed knowledge of how the Bouncer system works. Google has said little publicly about its capabilities, preferring not to give attackers any insights into the system's inner workings. So Oberheide and Miller looked at it as a challenge, an exercise to see how much they could deduce about Bouncer from the outside, and, as it turns out, the inside."