Locked or unlocked? It's not really clear, but reading between the lines it sounds like this only works with an unlocked phone that trusts the computer. Like they built a version of naughty iTunes that does bad things when you sync with it.
If your computer is infected by malware, at that point they could just get cookies and stuff from the computer itself...
Mobile devices have much more interesting data these days. I doubt your computer has a detailed log of your location, your entire contact book, and unprotected tokens for services.