242 Handbook of SCADA/Control Systems Security
3. Missing HMI stations
4. Full network emergency: go-safe-mode
Clearly the latter is dangerous and disruptive, but it is less dangerous than leaving
things just as they are. To make a controller aware of these problems, it would be
wise to purchase switches that communicate using industrial protocols as well as
SNMP. If a port that is normally live goes dead, there may be options to build in to
the control system narrative that can react to problems like this.
The use of TCP/IP networks has tended to make people sloppy about choosing
appropriate media for the plant. In particular, there is a disturbing trend among many
control systems vendors to use wireless IEEE 802.11 and IEEE 802.15.4 devices ...