I'd be interested to see what kind of malware it is. Is it just a EXE that does bad things to your computer but still requires executing and clicking the confirm button (since it is probably not signed). If so, what decicdes does it target? I always feel fairly save on my iPhone because there are currently no exploits we know about (and I think a hacker is smart enough not to let it loose on the wild. He would only use it for targeted attacks since such an exploit is worth a lot of money and would get detected eventually). On my phone I also can't excute Apps from outside the AppStore (I know there are profiles and enterprise certificate but that process is a little suspicious).

Also, if the hacker already conpromised one app, what could he possibly want to infect if the app is already effected.

What I think is that an ad company is too generous with their user data and somebody just bought an ad that only targets that geographical region . That would explain the territori.