reads the April NRC filing by FirstEnergy's Dale Wuokko. "[S]ome
people in Corporate's Network Services department were aware of this
T1 connection and some were not."
Users noticed slow performance on Davis-Besse's
business network at 9am, Saturday, 25 January, at the same time
Slammer began hitting networks around the world. From the business
network, the worm spread to the plant network, where it found purchase
in at least one unpatched Windows server. According to the reports,
plant computer engineers hadn't installed the patch for the MS-SQL
vulnerability that Slammer exploited. In fact, they didn't know there
was a patch, which Microsoft released six months before Slammer
By 4pm, power plant workers noticed a
slowdown on the plant network. At 4:50pm, the congestion created by
the worm's scanning crashed the plant's computerized display panel,
called the Safety Parameter Display System.
An SPDS monitors the most crucial safety
indicators at a plant, like coolant systems, core temperature sensors,
and external radiation sensors. Many of those continue to require
careful monitoring even while a plant is offline, says one expert. An
SPDS outage lasting eight hours or more requires that the NRC be
At 5:13pm, another, less critical,
monitoring system called the "Plant Process Computer" crashed. Both
systems had redundant analog backups that were unaffected by the worm,
but, "the unavailability of the SPDS and the PPC was burdensome on the
operators," notes the March advisory.
It took four hours and fifty minutes to
restore the SPDS, six hours and nine minutes to get the PPC working
FirstEnergy declined to elaborate on the
incident. The company has become the focus of an investigation into
last week's northeastern US blackout. Though the full cause of the
blackout has yet to be determined, investigators have reportedly found
that it began when an Ohio high-voltage transmission line "tripped"
after sagging into a tree. An alarm system that was part of
FirstEnergy's Energy Management System failed to warn operators at the
company's control center that the line had failed.
Asked if last week's Blaster worm might
have had a hand in the alarm system failure, just as Slammer disabled
the Davis-Besse safety display panel, FirstEnergy spokesman Todd
Schneider said: "We're investigating everything right now."
"I have not heard of anything like that,"
added Schneider. "The alarm system was the only system that was not
The Davis-Besse incident was not Slammer's
only point of impact on the electric industry. According to a document
released by the North American Electric Reliability Council in June,
Slammer downed one utility's critical SCADA network after moving from
a corporate network, through a remote computer to a VPN connection to
the control center LAN.
A SCADA (Supervisory Control and Data
Acquisition) system consists of central host that monitors and
controls smaller Remote Terminal Units (RTUs) sprinkled throughout a
plant, or in the field at key points in an electrical distribution
network. The RTUs, in turn, directly monitor and controls various
pieces of equipment.
In a second case reported in the same
document, a power company's SCADA traffic was blocked because it
relied on bandwidth leased from a telecommunications company that fell
prey to the worm.
Reports on the effect of last week's
Blaster worm on the electric grid, if any, have yet to emerge.
The Slammer attacks came after years of
warnings about the vulnerability of power plants and electric
distribution systems to cyber attack. A 1997 report by the Clinton
White House's National Security Telecommunications Advisory Committee,
which conducted a six-month investigation of power grid cybersecurity,
described a national system controlled by Byzantine networks riddled
with basic security holes, including widespread use of unsecured SCADA
systems, and ample connections between control centers and utility
company business networks.
"[T]he distinct trend within the industry
is to link the systems to access control center data necessary for
business purposes," reads the report. "One utility interviewed
considered the business value of access to the data within the control
center worth the risk of open connections between the control center
and the corporate network."
Future Safety Concerns
An energy sector cybersecurity expert
who's reviewed nuclear plant networks, speaking on condition of
anonymity, said the trend of linking operations networks with
corporate LANs continues unabated within the nuclear energy industry,
because of the economic benefits of giving engineers easy access to
plant data. An increase in plant efficient of a couple percentage
points "can translate to millions upon millions of dollars per year,"
says the expert.
He says Slammer's effect on Davis-Besse
highlights the dangers of such interconnectivity.
Currently, U.S. nuclear plants generally
have digital systems monitoring critical plant operations, but not
controlling them, said the expert. But if an intruder could tamper
with monitoring systems like Davis-Besse's SPDS, which operators are
accustomed to trusting, that could increase the risk of an accident.
Moreover, the industry is moving in the
direction of installing digital controls that would allow for remote
operation of plant functions, perhaps within a few years, if the NRC
approves it. "This is absolutely unacceptable without drastic changes
to plant computer networks," says the expert. "If a non-intelligent
worm can get in, imagine what an intruder can do."
Jim Davis, director of operations at the
Nuclear Energy Institute, an industry association, says those concerns
are overblown. "If you break all the connections and allow no data to
pass from anywhere to anywhere, you've got great security - but why'd
you put the digital systems in the first place?," says Davis.
Davis says the industry learned from the
Davis-Besse incident, but that the breach didn't prove that
connections between plant and corporate networks can't be implemented
securely. "You can put a well-protected read-only capability on a data
stream that provides you reasonable assurance that nobody can come
back down that line to the control system," says Davis.
Last year the NEI formed a task force to
develop updated cybersecurity management guidelines for the industry.
The results - which will be secret - are expected within a few months.
As part of a research effort earlier this year, the NEI's task force
worked with the NRC and a contractor to review cybersecurity at four
nuclear power plants. The details of the review are classified as
"Safeguards" material, but Davis says the investigation found no
serious problems. "There are no issues that generate a public health
and safety concern," says Davis.
"Sometime people get very anxious about
digital systems and what you could or couldn't do with digital
systems, but in lots of cases you've got switches and valves and
little override buttons on this thing and that thing that could cause
a component to shut down as quickly as any digital system," Davis
Despite the Slammer breach, FirstEnergy
was apparently not in violation of NRC's limited, and aging,
cybersecurity regulations. For its part, the commission wouldn't
comment on the incident. The NRC has faced fierce criticism for not
acting sooner to curb far more serious physical safety problems at the