How secure is your PLC?
any people fall into the
trap of thinking that their
business activities are of no
value to hackers, and that
therefore they’re unlikely
to become a target for a cyberattack.
However, all data and/or processes could
be of value to somebody, whether it’s
obtained via industrial espionage, state
sponsored hacking, or organised crime
and extortion. Protecting critical processes
against cyberattack has never been so
important.
transport layer security) is
a handshake protocol that
automatically generates
a cipher to encrypt and
decrypt communications
for a session between
authenticated devices. This
prevents unauthorised
devices from being able
to communicate with the
controller. SSL/TLS uses
digital certificates for
authentication while some
other protocols do not.
M
A programmable logic controller (PLC) is a
critical part of process industry automation
infrastructure, and disabling one could
take everything under its control with it.
This can make them high value targets for
hackers.
When many of the fieldbus protocols used
by PLCs, such as PROFINET and Modbus,
were first developed, the focus was on
maximising speed, functionality and
reliability rather than security. Modbus, for
instance, transmits data in plain text and
has no protection against unauthorised
access or interception of data. It therefore
falls to the PLC to provide the required
layers of security to protect systems
against attack.
PLC cybersecurity has come a long way
in recent years, but the long lifespan of
a typical PLC means that a company’s
installed base may well predate these
advances. Cybersecurity simply wasn’t
the risk even 20 years ago that it is today.
Retrofitting security features into existing
controllers can be difficult, as older PLCs
will often have very little memory and/
or CPU power to spare for adding in
new features. So the challenge is how
to upgrade PLC cybersecurity without
causing too much disruption.
Today‘s PLCs come packed with a variety of
encryption protocols, VPNs (virtual private
networks) and firewall capabilities to
minimise the risk of unauthorised access.
The appropriate combination of security
measures for a particular controller will
depend on how it is used. Much like a
castle might have a moat, drawbridge,
portcullis, high walls and turrets, no single
one of these will deter all attacks on their
own. They are instead elements of the
overall security package, and are used in
combination to protect systems. So it is
with PLC cybersecurity.
For example:
•
SSL/TLS (secure sockets layer/
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PECM Issue 27
•
•
•
SSH (secure shell) is a
similar form of security that
provides a secure channel
over an unsecured network.
This can be used for remote
logins to devices, which is
not possible using SSL/TLS
alone. SSH can potentially
enable secure access from
anywhere in the world,
assuming the user has the correct
passwords.
VPN (virtual private network) extends
a private network across a public
one, creating a secure virtual tunnel
between devices, as if they were
directly connected next to one
another.
Firewalls monitor and react to
incoming and outgoing traffic,
forming a barrier between the internal
network and other, potentially non-
secure networks like the internet. It
can help detect a DDoS attack, but
is not always effective at defending
against one in progress.
No system is completely infallible, but
features like those described can help to
reduce the likelihood of unauthorised
access. However, it’s important to
remember that these protections are
largely meaningless if passwords are
compromised, which is why many hackers
increasingly use phishing attacks to
prey on human error rather than any
vulnerabilities in the system. It’s therefore
crucial to keep passwords safe and
secure, and to regularly change them, as
the protections are only as strong as the
humans who use it.
WAGO’s PFC100 and PFC200
programmable logic controllers include a
wide range of the latest security protocols,
including SSL/TLS, SSH, VPN and firewall,
as well as others such as IPsec, HTTPS and
more. This affords users the flexibility to
use the appropriate protocols based on
how the controller is used while ensuring
a high level of security. The controllers are
also compatible with all major fieldbus
protocols, making installation quicker and
allowing the WAGO PLC to work happily
with devices from other vendors.
Compatibility means users aren’t locked
in to a proprietary protocol or language,
as they can use what they’re already
familiar with, and the installed base can
be updated gradually rather than all
at once. The Linux operating system is
open-source, allowing users to access and
develop patches for the source code.
PLCs are just one of the many devices in
a plant that must be considered in the
context of cyber security protection. But
considering its importance at the centre
of a plant’s operations, it is vital to utilise
the latest features and technologies in
protecting against attacks.
WAGO Limited
Visit: www.global.wago.com/uk
Telephone: 01788 568008
Email: [email protected]