Physical And Environmental Considerations - Honeywell 900U02-0100 User And Installation Manual

3.4.

Physical and Environmental Considerations

The physical security of a process control network is particularly important. If the hardware is rendered
inoperable, the entire system (and hence the plant) is rendered inoperable.
Protecting against unauthorized system access
External media drives can enable anyone to bypass Windows security and gain access to your system.
If there is an easy access to a computer, and it has a floppy disk or CD drive, it can be booted from an
alternative operating system. This can be used to circumvent file system security, and could be used to
install damaging software, or even to reformat the hard disk.
It is therefore of critical importance in relation to the nodes in your process control network that you
prevent the use of all unauthorized removable devices and media such as CDs, DVDs, floppy disks, and
USB memory sticks.
There are several other steps that can be taken to reduce the risk of unauthorized access, including:

Setting the BIOS to boot only from the C drive.

Setting a BIOS password (check that this does not prevent automatic startup).

Physically securing the computer (for example, in a locked room or cabinet) or fitting locks to the
floppy and CD drives.

Removing (in extreme cases) the floppy and CD drives from the computer.

Disabling USB ports and other ports capable of being used for memory sticks and other portable
storage devices.
Control room access
Providing physical security for the control room is essential to reduce the potency of many threats. The
area often contains the Engineering Workstation, ControlEdge HC900 system. Limiting those who can
enter this area, using smart or magnetic identity cards, biometric readers and so on is essential. In extreme
cases, it may be considered necessary to make the control room blast-proof, or to provide a second off-
site emergency control room so that control can be maintained if the primary area becomes uninhabitable.
Network and controller access
ControlEdge HC900 controller is an intelligent programmable device, with the ability to be manipulated
through loader software running on a laptop or similar computer connected directly to it. To prevent
unauthorized tampering, the controllers and network equipment must be physically protected in locked
cabinets, and logically protected with passwords or other authentication techniques. Network cables are
also vulnerable to damage or unauthorized connection. For maximum protection, cabling must be
duplicated and laid in separate hardened cable runs.
Physical access to critical devices
The malicious operation on the critical ControlEdge HC900 modules like Controller module, Scanner
Module, network switches for IO network and host communication network, I/O Modules or Power
supply modules will result in system shutdown, starting the system expectedly or impact process control.
For maximum security, the ControlEdge HC900 system must be placed in a cabinet or locked closet to
protect against unauthorized access to the critical modules.
Revision 10 ControlEdge HC900 Process & Safety Controller User and Installation Manual
May 2019
43