Search Fu is failing me today. I am looking find out more information about what happens when a hacker is attacked by black IC. By the way the RAW reads, when a user is successfully attacked by a black IC his connection is jammed open. So he cannot log off except if he pulls his plug.

Does this do anything else to the hacker? Say for example is he stuck in HOT sim if he got attacked in HOT? or can he back out to AR?

It doesn't say, but I would assume they are locked in VR mode. So the only way out is pulling the plug - Removing the trode net, flipping the VR switch. These will remove the hacker from harm (minus the dumpshock), but his connection will still run idle allowing him to be tracked. Once he's suffered the dumpshock he should be able to pick it up again via AR I would think. So once hit you're stuck till the IC is defeated or you jack out and suffer the dumpshock.

i would say that going to AR from VR while under a black ice attack would be the same as jacking out, in rules terms. as in, one would need to test for it...