Mother clicked an unverified link that was sent via SMS to her, installed the app, then ran it.
The app proceeded to hijack her kakao talk messenger app (which is used by nearly all people in Korea), change the password and email, then sent messages to her friends and relatives talking about how she urgently needed $1000 or so, would you please send it to <bank account provided>. She didn't know until a friend asked her why she needed $1000 by phone; if the friend had asked by Kakaotalk, she might have been swindled by the conman sitting on the other side.
@.@ I never knew you could hijack another app...
So continues the trend of technologically impaired old people mucking up their devices with something that could have easily been avoided.
Nah, there's a bunch of apps out there right now that, once you download them, will just wreak havoc with your phone. People hide tons of code in those things because no one ever bothers to open them up and find out what makes them tick. This one that Skyrunner's mom downloaded was just slightly more malicious than others.
On the American app market alone there's like 4 "flashlight" apps that send off data about you back to their creators. It only takes a couple of kilobytes (90 KB from what I heard) to make a flashlight app, and a couple of those are around 2-3 MBs. Data about consumers is currently the best product that app producers can generate, some people like to skip the middleman though and try to extort their customer database. It usually lands them behind bars somewhere.
FAKEEDIT: WHY AM I ALWAYS THE FIRST POST ON A PAGE!? AGH.