full list of matrix actions is on pg 229+ SR4a, you can crash a node as a complex action
"Crash Node (Exploit)
You crash a node (not a persona) that your icon is currently accessing.
Make a Hacking + Exploit (System + Firewall, Complex Action)
Extended Test. When you reach the threshold, the node is crashed
and reboots (p. 238). The node issues a restricted alert against the
attacker when it is first attacked (which grants the node a +4 to
Firewall among other effects listed on p. 238). Any users accessing
the node via VR must resist Dumpshock when the node crashes, including
the hacker."