The Android malware scanner called Bouncer, which Google uses toscrutinize all apps uploaded to Google Play, can be easilybypassed, a pair of security researchers said on Monday. Mobile security researchers Jon Oberheide and Charlie Miller havedevised several methods that could allow malicious apps todetermine when they are being inspected by Google's scanner andhide their real purpose. [ Security expert Roger A. Grimes offers a guided tour of thelatest threats and explains what you can do to stop them in " Fight Today's Malware ," InfoWorld's Shop Talk video.
Learn how to secure your systemswith InfoWorld's Security Central newsletter , both from InfoWorld. ] In February, Google revealed that it uses an in-house developedservice called Bouncer to scan all apps that are made available fordownload or purchase on Google Play -- then known as the AndroidMarket -- for signs of malware. The company explained that Bouncerexecutes every newly uploaded app inside an Android emulator andanalyzes its behavior. Antivirus programs have long used built-in emulators to safelyobserve how suspicious files behave when executed and mostantivirus experts analyze malware samples in virtual machines.
As aresult, a lot of malware programs are now designed to suppresstheir malicious behavior if they detect the use of emulatedenvironments. Oberheide and Miller took a similar approach in their attempt tobypass Bouncer. "If you know your app is running in Bouncer, youjust play dead," Oberheide said via email. "If you know your app isoutside Bouncer on a real user's device, then you just pull downyour root exploit from an external server." The two researchers created an app that connects back to theirserver and allows them to issue basic Linux commands on the Androiddevice where it runs. This is known as a connect-back shell and canbe opened by apps that don't require special Android permissions.
The researchers created a fake Google Play developer account, whichOberheide says is pretty easy to do, and submitted the app. When itgot executed by Bouncer inside its Android emulator for analysis,the app called back home and allowed the researchers to gatherinformation about the environment. Using the connect-back shell opened by the app, Oberheide andMiller were able to identify bits of information that are unique tothe Bouncer system and can act like a fingerprint. Malicious appscan use this fingerprint to determine whether the system they runin is Google's scanner or a real device.
However, the connect-back shell is not the only method that can beused to fingerprint Bouncer, Oberheide said. The researchers planto showcase several techniques they developed for this purpose onFriday, at the SummerCon conference in New York. "We've been in touch with the Android security team and will beworking with them to address some of the problems we'vediscovered," Oberheide said in a blog post on Monday. However, the researcher doesn't believe that all fingerprintingtechniques will be easy to block, because Google needs to keep theratio of false positive detections at a low level. "If your app can fingerprint Bouncer using the same commonoperations that millions of apps use, then Google will be unable toflag it since it would be infeasible to also flag those millions ofapps," Oberheide said via email.
Making Bouncer impossible to fingerprint by removing all signs thatit uses an emulated environment would also be extremely difficult,Oberheide said. However, its current state can be improved, hesaid. Google did not immediately return a request for comment. I am a professional writer from Rattan Products, which contains a great deal of information about pine trundle bed , oak trundle bed, welcome to visit!
Related Articles -
pine trundle bed, oak trundle bed,
|
