Can an Android app be hacked to any effect?

Does anyone know if an app can be hacked 开发者_JAVA百科to manipulate anything else beside the actual app or the host phone itself? A web service server perhaps? Is that even possible? So the real question is, if an app is hacked, can the information it might possess or has access to be used for negative purposes?

(I'm looking to secure an app, not hack anyone.) :)

Web services are always vulnerable to being hacked. This is why you use a secure connection such as SSL to transfer any sensitive information.

As far as directly hacking Android applications, I imagine a hacker would have to do something along the lines of decompiling an application to assembly, much as they do for traditional applications.

Any kind of storage on the device in non-compiled format (some XML, text files, preferences) is more vulnerable to being hacked than natively compiled .apk's.

I think everything is hackable... It is quite easy to get access to all your application's data on a rooted device. Things like your database or your private files are accessible on a rooted device.