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Automation networks & Security 107
Decision
The classic firewall protects against hackers, worm viruses and spyware. The software programmes
protect the network or the specific computer against the outside world and allow
only trusted messages to pass. One of the objectives is to block all suspect programmes
that look for a connection with the Internet from the own location. In addition, there are
programmes in the office IT such as anti-virus programmes, anti-spyware and anti- adware
programmes that block every inbound file, check for threats hidden within the database and
then declare the file clean or place it in quarantine. They also screen all called up files for the
presence of viruses, spyware and adware that are included in the database. The principle
of this IT protection is that the firewall views and analyses all inbound and outbound data
traffic, data files, programmes,... Such firewalls slow down the system and can even prevent
the programme from functioning, if necessary.
In order to realise a more industry-compatible firewall, techniques will have to be used that
guarantee in the first place that there will be no delays and still guarantee security and
reliability. One can use safe communication channels between, e.g., PLC and the master
computer or data servers. In order to ensure real-time functioning, no delay should occur
when checking the data that pass that firewall. Other technologies will have to be applied.
An option is to check the applied protocols instead of the actual data.
9.3.5 Standardisation with regard to security in automation networks
Introduction
ANSI/ISA 99 gives directives for the carrying out of risk assessment, the setting up of a socalled
cyber security management and carrying out that management. The standard is set
up in collaboration with end users, system integrators and suppliers. The ANSI/ISA 99 norm
is currently under development. Currently, 2 parts are available.
Figure 9.4: The ANSI/ISA 99 standard
Figure 9.4 shows an overview of the ISA 99 standard. Part 1 is meant to be a framework
around all the other parts. At the moment, only part 1 and part 2.01 are available.