POWER February 2014 - 43

INSTRUMENTATION & CONTROL
the years, with pure IP, Ethernet to serial converters, and serial servers
becoming good options for reliable communication but coming with
an additional risk as well.
Prioritize Patching for Exposed Systems
In my experience, generation engineers are concerned about the risk of
patching systems. The reasoning is that patches can often introduce unknown
elements to what is a functioning system. This view is supported
by anecdotes of patches that have negatively affected operations. Additionally,
patching comes with additional manpower and testing costs,
ones that should be evaluated before undertaking a patch.
Not patching runs a similar risk as not fixing a piece of equipment
when there is a known problem. For instance, if a pump has a tendency
to overheat, the decision might be to limit usage and to watch
closely for problems.
However, a " watch and see " approach in cybersecurity is based on
a faulty assumption that tools and personnel are available who can
recognize a cybersecurity compromise at the same level as they can
diagnose and troubleshoot an overheating pump. Even many security
professionals can have difficulty recognizing malicious code in the
wild without considerable experience and investment. This level of
capability simply does not exist at most generation plants, and it is not
a core function of making electric power.
Unpatched systems are vulnerable to simple exploits, many of
which have point-and-click usage. Without periodic patching, systems
would remain vulnerable forever, awaiting a motive to compromise.
Patching every time a vulnerability is discovered is a worthy goal but
is not appropriate for a generation environment. What is needed is a
more intelligent process that patches based on risk and that limits risk
to the control system.
Prioritized patching is an approach that ensures that systems with
the most exposure to the outside world are patched first, and other
systems follow on a set schedule. No matter what, control system
engineers should set the patch schedule for their control systems and
never patch a system when it can affect operations. Digital Bond has
used three tiers:
Made in Switzerland
■ Tier 1: Patch systems with external connections as soon as possible
after testing.
■ Tier 2: Patch systems that can communicate with Tier 1 systems
during biannual outages.
■ Tier 3: Patch everything else at least annually.
Ideally, Tier 1 systems are those systems that would not have
an impact on operation. Specifically, these would be things like
external-facing historians, performance-monitoring systems,
remote access, and human-machine interfaces (HMIs) not used
by operators. Tier 2 systems would be interface systems, those
responsible for passing data to and from Tier 1 systems. They
would ideally not have a major control function, and should be
patched on a scheduled basis. Tier 3 consists of critical devices
and systems that, if compromised, could affect the production of
electric power.
The risk of not patching everything in an IT environment would be
that viruses could spread throughout the environment quickly. However,
control systems are already so vulnerable that simply being on the
same network as a control system would allow an attacker much more
capability than using an exploit.
Say No to Indiscriminate Use of Technician Laptops
Laptops are the newest tools at a generation site. Turbine tuning is
routinely done with a laptop and a set of sensors, and protection relays
are configured as well. Most major control system vendors have stanFebruary
2014 | POWER
www.powermag.com
Features
 Battery-powered instrument for
standalone operation.
 Equipped with hyperterminal
interface for logger download and
sample flow monitoring device.
 Optional: Quality certificate for quality
assurance of process analyzers.
 Step-by-step instruction manual as a
Standard Operating Procedure (SOP).
Ask for technical documentation
or check our homepage
www.swan.ch
www.swan.ch · SWAN ANALYTISCHE INSTRUMENTE AG
8340 Hinwil/Switzerland · Phone +41 44 943 63 00
CIRCLE 15 ON READER SERVICE CARD
43
ANALYTICAL INSTRUMENTS
Monitor AMI INSPECTORS -
Portable Inspection Equipment
 Resistivity
 Dissolved Oxygen
 pH
 Specific Conductivity
 Hydrogen
http://www.swan.ch http://www.swan.ch http://www.powermag.com
POWER February 2014

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