I'm not quite sure how it would be done, but some sort of reversed tower defense game would probably be pretty interesting. I like how Guns'n'Glory made it so you could move your "towers" (men) vs. having set locations. Having a game where you have to control units to get through a gauntlet of towers by both avoiding and attacking certain locations in order to get through seems like it would be fairly entertaining, and also slightly different from the current mound of games in this genre.
There was a game on xbox live that was tied to the game Dead Space. I don't remember what it was called but you had to hack security systems and on of the ways was kind of like a what your talking about. You had three different types of "viruses" that you could send in. Pretty fun
Plus it's not on mobile phones, but this is pretty much exactly the premise for the PC game Anomaly: Warzone Earth.
