QUOTE (Evilness45 @ Mar 11 2010, 02:35 PM)
Ok, my character often hack with as an admin, because it's fairly easy.
Once I'm hacked inside, what could trigger an IC?
Like, once I'm the admin, what can stop me?
Well, the biggest thing that can trigger IC would be an active security spider -- they can make Matrix Perception tests (versus your Stealth, of course) to determine that you got admin access without actually having an account.
On top of that (assuming that the security model for the node in question factors this in), a spider running security audits on the system can detect your "probing the target" exploit before you have a chance to log in, if you take too long to take advantage of it.
The ever-popular GM Caveat can always trump you, as well -- one rather creative one that was used against me when I was breathing the heady air of Hubris Mountain was a hacking attempt by a (woefully unskilled) NPC hacker that prompted a (alarm-free) node reboot.
A system that requires a passkey can automatically throw an alarm up if you don't actually possess a valid passkey (regardless of your hacked user access) -- unless you hack the Access Log after every matrix action you have the node take. (Like encryption, this mostly serves to slow you down, rather than actively prevent you from doing things). (As an aside, despite the text in Unwired implying that only the most secure nodes require a passkey, it seems that almost every potentially interesting node I've come across in adventures requires passkey access).
Someone has already mentioned the Kitsune IC...aside from that, a node with sufficient resources could run Analyze on every icon present.
That's all just off the top of my head. Like so many other things in Shadowrun, the main thing that will keep you from being able to take advantage of your admin access is GM/Story caveat. There are ways to make any given node virtually unhackable to anything but the most uber of hackers (the types that FastJack looks up to). "Realistically," probably every node that a runner would be likely to *want* to hack into would be virtually impossible to get into...but that wouldn't be very fun for the sad sack who opted to play a hacker. No matter how challenging it might be for the player, any adventure that *requires* hacking to complete should have some way for the players to complete it, and any adventure that can be completely trivialized by hacking should have some way to prevent that.
(I'm not advocating a blanket cockblockery of a well-planned Matrix assault, BTW. I'm just saying that no run should end right after the meeting with Mr.Johnson by the hacker immediately rolling Hacking+Exploit and beating a threshold.)