QUOTE (Yerameyahu @ May 6 2011, 11:27 PM)

I didn't say they couldn't do that. I was referring to the idea that agents remain on the commlink after shutdown. It seems to be stealing the raison d'etre of viruses, which explicitly do that.
SR viruses didn't exist to me at the time, since I didn't have the right book for them. I still don't see why an agent couldn't be particularly insidious.
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Since you mention it again, I still find it odd to gloss over the difficulty of hacking an admin account, and making several major changes, *especially* if it's an agent doing this alone. 'Sufficiently advanced' is a total copout.

Crappy commlink + crappy Analyze + acting in AR with 1 IP + not paying attention. The agent legitimately hacked his commlink undetected and performed the right actions. Dice rolls, even, not fiat.
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And in what universe is getting your admin account hacked "a minor annoyance"? These ideas aren't compatible. Yes: if you've (secretly) hacked an admin account, all bets are off. There's really no reason to talk about it, because you're done; you win. There aren't many reasons you'd *bother* installing a zombie at that point.
Sure, you could kick off and delete every legitimate user account, but that's going to end in the commlink getting shut down immediately, wiped, and reloaded. Hackers can't resist a challenge, and the clock is ticking on that response team showing up. If a corp wants to "retrieve" personnel and equipment, the best way is to tie people up until the corp can get a team on-site, not break all their toys so they'll run away and be untraceable.
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Since we're making assumptions, I'm assuming that a hacker can start his own comm in Safe Mode/Single User Mode, which doesn't run a startup script and doesn't allow any other accounts to log in or do anything. Problem solved.

"Assume" was the wrong word. It's really an inference. While Safe Mode / Single User Mode is unnecessary to the operation of the commlink (or any commlink functions described in the game), the ability to load agents and programs
is necessary to the game, so there must be some in-game action that allows you to do so. Since an admin account is the top-level access to a node, the power to do this must necessarily lie, at the very least, at that level.
The only other options I can come up with are these:
1) There is some special unmentioned access level that allows the loading of agents and programs, or
2) You can't load programs or agents.
Since 2) makes the game unplayable, and 1) is not in any way inferable, I'm left with my reasonable inference that admin accounts allow for this sort of activity.
Considering the book says
QUOTE (SR4A p225)
An admin (short for administrator) account grants a user full access to the node. No action or command is denied to an admin account.
I find that position fairly justified.
Every possible reasonable action can't possibly be outlined in a rulebook.