No, it appears to be stand-alone and it spreads by using the AutoRun feature - it infects removable drives and flags the files as System files so they do not show up in Explorer - when an infected USB drive is plugged into a clean system, the AutoRun feature infects the clean system.
Also it does affect fully-patched XP systems. I sent samples to various anti-virus vendors (F-Secure, CA, Mcafee) and all respond that it is the RJump worm. Unfortunately Avast does not detect it yet. I sent a sample but it is still undetected...which is why I am posting in this discussion group. It makes me wonder a bit about the effectiveness of the Avast product. Although the free version is great for home use (can't argue with the price). I'm hoping that the defs will be updated soon.
Best regards
Graham