Together with my former colleagues Ravi, Patrick, Jean-Pierre from TU Berlin / SecT I have been working on an enhancement for mobile phones in order to protect SMS messages especially mTANs against trojans.
We investigated several ways to improve mTAN security and finally came to the conclusion that we just need to change the SMS routing on the mobile phone itself.
Basically we remove SMS messages that contain mTANs from the normal delivery queue and only deliver them to a special application. This way no other program (including trojans) can access the SMS message.
We implemented and tested our idea on Android. The paper SMS-based One-Time Passwords: Attacks and Defense will be presented at DIMVA 2013 in July in Berlin, Germany.
A demo video of the prototype is shown below: