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United States General Accounting Office:



Before the Subcommittee on Technology Information Policy, 
Intergovernmental Relations and the Census, House Committee on 
Government Reform:

For Release on Delivery Expected at 2 p.m. EST Tuesday, March 30, 2004:


Challenges and Efforts to Secure Control Systems:

Statement of Robert F. Dacey,

Director, Information Security Issues:


GAO Highlights:

Highlights of GAO-04-628T, a testimony before the Subcommittee on 
Technology, Information Policy, Intergovernmental Relations and the 
Census, House Committee on Government Reform 

Why GAO Did This Study:

Computerized control systems perform vital functions across many of our 
nationís critical infrastructures. For example, in natural gas 
distribution, they can monitor and control the pressure and flow of gas 
through pipelines. In October 1997, the Presidentís Commission on 
Critical Infrastructure Protection emphasized the increasing 
vulnerability of control systems to cyber attacks. At the request of 
the House Committee on Government Reform, Subcommittee on Technology, 
Information Policy, Intergovernmental Relations and the Census, this 
testimony will discuss GAOís March 2004 report on potential cyber 
vulnerabilities, focusing on (1) significant cybersecurity risks 
associated with control systems (2) potential and reported cyber 
attacks against these systems (3) key challenges to securing control 
systems, and (4) efforts to strengthen the cybersecurity of control 

What GAO Found:

In addition to general cyber threats, which have been steadily 
increasing, several factors have contributed to the escalation of the 
risks of cyber attacks against control systems. These include the 
adoption of standardized technologies with known vulnerabilities and 
the increased connectivity of control systems to other systems. Typical 
control system components are illustrated in the graphic below. Control 
systems can be vulnerable to a variety of attacks, examples of which 
have already occurred. Successful attacks on control systems could have 
devastating consequences, such as endangering public health and 

Securing control systems poses significant challenges, including 
limited specialized security technologies and lack of economic 
justification. The government, academia, and private industry have 
initiated efforts to strengthen the cybersecurity of control systems. 
The Presidentís National Strategy to Secure Cyberspace establishes a 
role for DHS to coordinate with these entities to improve the 
cybersecurity of control systems. While some coordination is occurring, 
DHSís coordination of these efforts could accelerate the development 
and implementation of more secure systems. Without effective 
coordination of these efforts, there is a risk of delaying the 
development and implementation of more secure systems to manage our 
critical infrastructures. 

What GAO Recommends:

In a March 2004 report, GAO recommends that the Secretary of the 
Department of Homeland Security (DHS) develop and implement a strategy 
for coordinating with the private sector and other government agencies 
to improve control system security, including an approach for 
coordinating the various ongoing efforts to secure control systems. DHS 
concurred with GAOís recommendation.

To view the full product, including the scope and methodology, click on 
the link above. For more information, contact Robert F. Dacey at (202) 
512-3317 or

[End of section]

Mr. Chairman and Members of the Subcommittee:

I am pleased to be here today to participate in the Subcommittee's 
hearing on the cyber vulnerabilities in industrial control systems. 
Control systems--which include supervisory control and data acquisition 
(SCADA) systems and distributed control systems[Footnote 1]--perform 
vital functions across many of our nation's critical infrastructures, 
including electric power generation, transmission, and distribution; 
oil and gas refining and pipelines; water treatment and distribution; 
chemical production and processing; railroads and mass transit; and 
manufacturing. In October 1997, the President's Commission on Critical 
Infrastructure Protection highlighted the risk of cyber attacks as a 
specific point of vulnerability in our critical infrastructures, 
stating that "the widespread and increasing use of SCADA systems for 
control of energy systems provides increasing ability to cause serious 
damage and disruption by cyber means.":

In my testimony today I will discuss the results of our recent report, 
which is being released today.[Footnote 2] As you requested, this 
report identifies (1) significant cybersecurity risks associated with 
control systems, (2) potential and reported cyber attacks against these 
systems, (3) key challenges to securing control systems, and 
(4) efforts to strengthen the cybersecurity of control systems.

In preparing our report, we analyzed research studies and reports, as 
well as prior GAO reports and testimonies on critical infrastructure 
protection (CIP), information security, and national preparedness, 
among others. We analyzed documents from and met with private-sector 
and federal officials who had expertise in control systems and their 
security. Our work was performed from July 2003 to March 2004 in 
accordance with generally accepted government auditing standards.

Results in Brief:

For several years, security risks have been reported in the control 
systems on which many of the nation's critical infrastructures rely to 
monitor and control sensitive processes and physical functions. In 
addition to a steady increase in general cyber threats, several factors 
have contributed to the escalation of risks specific to control 
systems, including the (1) adoption of standardized technologies with 
known vulnerabilities, (2) connectivity of control systems with other 
networks, (3) insecure remote connections, and (4) widespread 
availability of technical information about control systems.

Control systems can be vulnerable to a variety of types of cyber 
attacks that could have devastating consequences--such as endangering 
public health and safety; damaging the environment; or causing a loss 
of production, generation, or distribution by public utilities. Control 
systems have already been subject to a number of cyber attacks, 
including attacks on a sewage treatment system in Australia in 2000 
and, more recently, on a nuclear power plant in Ohio.

Securing control systems poses significant challenges. These include 
the limitations of current security technologies in securing control 
systems, the perception that securing control systems may not be 
economically justifiable, and conflicting priorities within 
organizations regarding the security of control systems.

Government, academia, and private industry have initiated several 
efforts that are intended to improve the security of control systems. 
These initiatives include efforts to promote the research and 
development of new technologies, the development of requirements and 
standards, an increased awareness and sharing of information, and the 
implementation of effective security management programs. The 
President's National Strategy to Secure Cyberspace establishes a role 
for the Department of Homeland Security (DHS) to coordinate with the 
private sector and other governments to improve the cybersecurity of 
control systems. While some coordination is occurring, DHS's 
coordination of these efforts could accelerate the development and 
implementation of more secure systems. Without adequate coordination of 
these efforts, there is a risk of delaying the development and 
implementation of more secure systems to manage our critical 

In our March report, we recommend that the Secretary of DHS develop and 
implement a strategy for coordinating with the private sector and other 
government agencies to improve control system security, including 
developing an approach for coordinating the various ongoing efforts to 
secure control systems. This strategy should also be addressed in the 
comprehensive national infrastructure plan that the department is 
tasked to complete by December 2004. DHS's concurred with our 
recommendation and agreed that improving the security of control 
systems against cyberattack is a high priority.


Cyberspace Introduces Risks for Control Systems:

Dramatic increases in computer interconnectivity, especially in the use 
of the Internet, continue to revolutionize the way our government, our 
nation, and much of the world communicate and conduct business. The 
benefits have been enormous. Vast amounts of information are now 
literally at our fingertips, facilitating research on virtually every 
topic imaginable; financial and other business transactions can be 
executed almost instantaneously, often 24 hours a day, and electronic 
mail, Internet Web sites, and computer bulletin boards allow us to 
communicate quickly and easily with an unlimited number of individuals 
and groups.

However, this widespread interconnectivity poses significant risks to 
the government's and our nation's computer systems and, more important, 
to the critical operations and infrastructures they support. For 
example, telecommunications, power distribution systems, water 
supplies, public health services, national defense (including the 
military's warfighting capability), law enforcement, government 
services, and emergency services all depend on the security of their 
computer operations. If they are not properly controlled, the speed and 
accessibility that create the enormous benefits of the computer age may 
allow individuals and organizations to eavesdrop on or interfere with 
these operations from remote locations for mischievous or malicious 
purposes, including fraud or sabotage. Table 1 summarizes the key 
threats to our nation's infrastructures, as observed by the Federal 
Bureau of Investigation (FBI).

Table 1: Threats to Critical Infrastructures Observed by the FBI:

Threat: Criminal groups; Description: There is an increased use of 
cyber intrusions by criminal groups who attack systems for monetary 

Threat: Foreign intelligence services; 
Description: Foreign intelligence services use cyber tools as part of 
their information gathering and espionage activities.

Threat: Hackers; 
Description: Hackers sometimes crack into networks for the thrill of 
the challenge or for bragging rights in the hacker community. While 
remote cracking once required a fair amount of skill or computer 
knowledge, hackers can now download attack scripts and protocols from 
the Internet and launch them against victim sites. Thus, while attack 
tools have become more sophisticated, they have also become easier to 

Threat: Hacktivists; 
Description: Hacktivism refers to politically motivated attacks on 
publicly accessible Web pages or e-mail servers. These groups and 
individuals overload e-mail servers and hack into Web sites to send a 
political message.

Threat: Information warfare; 
Description: Several nations are aggressively working to develop 
information warfare doctrine, programs, and capabilities. Such 
capabilities enable a single entity to have a significant and serious 
impact by disrupting the supply, communications, and economic 
infrastructures that support military power--impacts that, according to 
the Director of Central Intelligence, can affect the daily lives of 
Americans across the country.[A].

Threat: Insider threat; 
Description: The disgruntled organization insider is a principal source 
of computer crimes. Insiders may not need a great deal of knowledge 
about computer intrusions because their knowledge of a victim system 
often allows them to gain unrestricted access to cause damage to the 
system or to steal system data. The insider threat also includes 
outsourcing vendors.

Threat: Virus writers; 
Description: Virus writers are posing an increasingly serious threat. 
Several destructive computer viruses and "worms" have harmed files and 
hard drives, including the Melissa macro virus, the Explore.Zip worm, 
the CIH (Chernobyl) virus, Nimda, and Code Red. 

Source: Federal Bureau of Investigation, unless otherwise indicated.

[A] Prepared statement of George J. Tenet, Director of Central 
Intelligence, before the Senate Select Committee on Intelligence, 
February 2, 2000.

[End of table]

Government officials remain concerned about attacks from individuals 
and groups with malicious intent, such as crime, terrorism, foreign 
intelligence gathering, and acts of war. According to the FBI, 
terrorists, transnational criminals, and intelligence services are 
quickly becoming aware of and using information exploitation tools such 
as computer viruses, Trojan horses, worms, logic bombs, and 
eavesdropping sniffers that can destroy, intercept, degrade the 
integrity of, or deny access to data.[Footnote 3] In addition, the 
disgruntled organization insider is a significant threat, because these 
individuals often have knowledge about the organization and its system 
that allows them to gain unrestricted access and inflict damage or 
steal assets without knowing a great deal about computer intrusions. As 
larger amounts of money and more sensitive economic and commercial 
information are exchanged electronically, and as the nation's defense 
and intelligence communities increasingly rely on standardized 
information technology (IT), the likelihood increases that information 
attacks will threaten vital national interests.

As the number of individuals with computer skills has increased, more 
intrusion or "hacking" tools have become readily available and 
relatively easy to use. A hacker can download tools from the Internet 
and literally "point and click" to start an attack. Experts agree that 
there has been a steady advance in the level of sophistication and 
effectiveness of attack technology. Intruders quickly develop attacks 
to exploit vulnerabilities that have been discovered in products, use 
these attacks to compromise computers, and share them with other 
attackers. In addition, they can combine these attacks with other forms 
of technology to develop programs that automatically scan networks for 
vulnerable systems, attack them, compromise them, and use them to 
spread the attack even further.

From 1995 through 2003, the CERTā Coordination Center[Footnote 4] 
(CERT/CC) reported 12,946 security vulnerabilities that resulted from 
software flaws. Figure 1 illustrates the dramatic growth in security 
vulnerabilities over these years. The growing number of known 
vulnerabilities increases the potential for attacks by the hacker 
community. Attacks can be launched against specific targets or widely 
distributed through viruses and worms.

Figure 1: Security Vulnerabilities, 1995-2003:

[See PDF for image]

[End of figure]

Along with these increasing vulnerabilities, the number of computer 
security incidents reported to CERT/CC has also risen dramatically--
from 9,859 in 1999 to 82,094 in 2002 and to 137,529 in 2003. And these 
are only the reported attacks. The Director of the CERT Centers has 
estimated that as much as 80 percent of actual security incidents goes 
unreported, in most cases because (1) there were no indications of 
penetration or attack, (2) the organization was unable to recognize 
that its systems had been penetrated, or (3) the organization was 
reluctant to report. Figure 2 shows the number of incidents that were 
reported to the CERT/CC from 1995 through 2003.

Figure 2: Computer Security Incidents, 1995-2003:

[See PDF for image]

[End of figure]

According to the National Security Agency (NSA), foreign governments 
already have or are developing computer attack capabilities, and 
potential adversaries are developing a body of knowledge about U.S. 
systems and methods to attack these systems. The National 
Infrastructure Protection Center (NIPC) reported in January 2002 that a 
computer belonging to an individual who had indirect links to Osama bin 
Laden contained computer programs that indicated that the individual 
was interested in the structural engineering of dams and other water-
retaining structures. The NIPC report also stated that U.S. law 
enforcement and intelligence agencies had received indications that Al 
Qaeda members had sought information about control systems from 
multiple Web sites, specifically on water supply and wastewater 
management practices in the United States and abroad.

Since the terrorist attacks of September 11, 2001, warnings of the 
potential for terrorist cyber attacks against our critical 
infrastructures have increased. For example, in his February 2002 
statement for the Senate Select Committee on Intelligence, the Director 
of Central Intelligence discussed the possibility of a cyber warfare 
attack by terrorists.[Footnote 5] He stated that the September 11 
attacks demonstrated the nation's dependence on critical infrastructure 
systems that rely on electronic and computer networks. Further, he 
noted that attacks of this nature would become an increasingly viable 
option for terrorists as they and other foreign adversaries become more 
familiar with these targets and the technologies required to attack 
them. James Woolsey, a former Director of Central Intelligence, shares 
this concern, and on October 29, 2003, in a speech before several 
hundred security experts, he warned that the nation should be prepared 
for continued terrorist attacks on our critical infrastructures. 
Moreover, a group of concerned scientists warned President Bush in a 
letter that "the critical infrastructure of the United States, 
including electrical power, finance, telecommunications, health care, 
transportation, water, defense and the Internet, is highly vulnerable 
to cyber attack. Fast and resolute mitigating action is needed to avoid 
national disaster." According to a study by a computer security 
organization, during the second half of 2003, critical infrastructure 
industries such as power, energy, and financial services experienced 
high attack rates.[Footnote 6] Further, a study that surveyed over 170 
security professionals and other executives concluded that, across 
industries, respondents believe that a large-scale cyber attack in the 
United States will be launched against their industry by mid-2006.

What Are Control Systems?

Control systems are computer-based systems that are used within many 
infrastructures and industries to monitor and control sensitive 
processes and physical functions. Typically, control systems collect 
sensor measurements and operational data from the field, process and 
display this information, and relay control commands to local or remote 
equipment. In the electric power industry, control systems can manage 
and control the generation, transmission, and distribution of electric 
power--for example, by opening and closing circuit breakers and setting 
thresholds for preventive shutdowns. Employing integrated control 
systems, the oil and gas industry can control the refining operations 
at a plant site, remotely monitor the pressure and flow of gas 
pipelines, and control the flow and pathways of gas transmission. Water 
utilities can remotely monitor well levels and control the wells' 
pumps; monitor flows, tank levels, or pressure in storage tanks; 
monitor water quality characteristics--such as pH, turbidity, and 
chlorine residual; and control the addition of chemicals. Control 
systems also are used in manufacturing and chemical processing. Control 
systems perform functions that vary from simple to complex; they can be 
used simply to monitor processes--for example, the environmental 
conditions in a small office building--or to manage most activities in 
a municipal water system or even a nuclear power plant.

In certain industries, such as chemical and power generation, safety 
systems are typically implemented in order to mitigate a potentially 
disastrous event if control and other systems should fail. In addition, 
to guard against both physical attack and system failure, organizations 
may establish backup control centers that include uninterruptible power 
supplies and backup generators.

There are two primary types of control systems. Distributed Control 
Systems (DCS) typically are used within a single processing or 
generating plant or over a small geographic area. Supervisory Control 
and Data Acquisition (SCADA) systems typically are used for large, 
geographically dispersed distribution operations. For example, a 
utility company may use a DCS to generate power and a SCADA system to 
distribute it. Figure 3 illustrates the typical components of a control 

Figure 3: Typical Components of a Control System:

[See PDF for image]

[End of figure]

Note: Remote/local stations can include one or more interfaces to allow 
field operators to perform diagnostic and maintenance operations. 
Sensors can measure level, pressure, flow, current, voltages, etc., 
depending on the infrastructure. Control equipment can be valves, 
pumps, relays, circuit breakers, etc., also depending on the 

A control system typically is made up of a "master" or central 
supervisory control and monitoring station consisting of one or more 
human-machine interfaces where an operator can view status information 
about the remote/local sites and issue commands directly to the system. 
Typically, this station is located at a main site, along with 
application servers and an engineering workstation that is used to 
configure and troubleshoot the other components of the control system. 
The supervisory control and monitoring station typically is connected 
to local controller stations through a hard-wired network or to a 
remote controller station through a communications network--which could 
be the Internet, a public switched telephone network, or a cable or 
wireless (e.g., radio, microwave, or Wi-Fi[Footnote 7]) network. Each 
controller station has a remote terminal unit (RTU), a programmable 
logic controller (PLC), or some other controller that communicates with 
the supervisory control and monitoring station.

The control system also includes sensors and control equipment that 
connect directly with the working components of the infrastructure--for 
example, pipelines, water towers, or power lines. The sensor takes 
readings from the infrastructure equipment--such as water or pressure 
levels, electrical voltage or current--and sends a message to the 
controller. The controller may be programmed to determine a course of 
action and send a message to the control equipment instructing it what 
to do--for example, to turn off a valve or dispense a chemical. If the 
controller is not programmed to determine a course of action, the 
controller communicates with the supervisory control and monitoring 
station and relays instructions back to the control equipment. The 
control system also can be programmed to issue alarms to the operator 
when certain conditions are detected. Handheld devices, such as 
personal digital assistants, can be used to locally monitor controller 
stations. Experts report that technologies in controller stations are 
becoming more intelligent and automated and are able to communicate 
with the supervisory central monitoring and control station less 
frequently, thus requiring less human intervention.

Control Systems Are at Increasing Risk:

Historically, security concerns about control have been related 
primarily to protecting them against physical attack and preventing the 
misuse of refining and processing sites or distribution and holding 
facilities. However, more recently, there has been a growing 
recognition that control systems are now vulnerable to cyber attacks 
from numerous sources, including hostile governments, terrorist groups, 
disgruntled employees, and other malicious intruders.

In October 1997, the President's Commission on Critical Infrastructure 
Protection discussed the potential damaging effects on the electric 
power and oil and gas industries of successful attacks on control 
systems.[Footnote 8] Moreover, in 2002, the National Research Council 
identified "the potential for attack on control systems" as requiring 
"urgent attention."[Footnote 9] In the first half of that year, 
security experts reported that 70 percent of energy and power companies 
experienced at least one severe cyber attack. In February 2003, the 
President clearly demonstrated concern about "the threat of organized 
cyber attacks capable of causing debilitating disruption to our 
Nation's critical infrastructures, economy, or national security," 
noting that "disruption of these systems can have significant 
consequences for public health and safety" and emphasizing that the 
protection of control systems has become "a national 
priority."[Footnote 10]

Several factors have contributed to the escalation of risk to control 
systems, including (1) the adoption of standardized technologies with 
known vulnerabilities, (2) the connectivity of control systems to other 
networks, (3) insecure remote connections, and (4) the widespread 
availability of technical information about control systems.

Control Systems Are Adopting Standardized Technologies with Known 

In the past, proprietary hardware, software, and network protocols made 
it difficult to understand how control systems operated--and therefore 
how to hack into them. Today, however, to reduce costs and improve 
performance, organizations have been transitioning from proprietary 
systems to less expensive, standardized technologies such as 
Microsoft's Windows, Unix-like operating systems, and the common 
networking protocols used by the Internet. These widely-used, 
standardized technologies have commonly known vulnerabilities, and 
sophisticated and effective exploitation tools are widely available and 
relatively easy to use. As a consequence, both the number of people 
with the knowledge to wage attacks and the number of systems subject to 
attack have increased. Also, common communication protocols and the 
emerging use of extensible markup language (commonly referred to as 
XML) can make it easier for a hacker to interpret the content of 
communications among the components of a control system.

Control Systems Are Connected to Other Networks:

Enterprises often integrate their control systems with their enterprise 
networks. This increased connectivity has significant advantages, 
including providing decision makers with access to real-time 
information and allowing engineers to monitor and control the process 
control system from different points on the enterprise network. In 
addition, the enterprise networks are often connected to the networks 
of strategic partners and to the Internet. Furthermore, control systems 
are increasingly using wide area networks and the Internet to transmit 
data to their remote or local stations and individual devices. This 
convergence of control networks with public and enterprise networks 
potentially creates further security vulnerabilities in control 
systems. Unless appropriate security controls are deployed in both the 
enterprise network and the control system network, breaches in 
enterprise security can affect the operation of control systems.

Insecure Connections Exacerbate Vulnerabilities:

Vulnerabilities in control systems are exacerbated by insecure 
connections. Organizations often leave access links--such as dial-up 
modems to equipment and control information--open for remote 
diagnostics, maintenance, and examination of system status. If such 
links are not protected with authentication or encryption, the risk 
increases that hackers could use these insecure connections to break 
into remotely controlled systems. Also, control systems often use 
wireless communications systems, which are especially vulnerable to 
attack, or leased lines that pass through commercial telecommunications 
facilities. Without encryption to protect data as it flows through 
these insecure connections or authentication mechanisms to limit 
access, there is little to protect the integrity of the information 
being transmitted.

Information about Infrastructures and Control Systems Is Publicly 

Public information about infrastructures and control systems is readily 
available to potential hackers and intruders. The availability of this 
infrastructure and vulnerability data was demonstrated last year by a 
George Mason University graduate student who, in his dissertation, 
reportedly mapped every business and industrial sector in the American 
economy to the fiber-optic network that connects them, using material 
that was available publicly on the Internet--and not classified.

In the electric power industry, open sources of information--such as 
product data and educational videotapes from engineering associations-
-can be used to understand the basics of the electrical grid. Other 
publicly available information--including filings of the Federal Energy 
Regulatory Commission (FERC), industry publications, maps, and material 
available on the Internet--is sufficient to allow someone to identify 
the most heavily loaded transmission lines and the most critical 
substations in the power grid. Many of the electric utility officials 
who were interviewed for the National Security Telecommunications 
Advisory Committee's Information Assurance Task Force's Electric Power 
Risk Assessment expressed concern over the amount of information about 
their infrastructure that is readily available to the public.

In addition, significant information on control systems is publicly 
available--including design and maintenance documents, technical 
standards for the interconnection of control systems and RTUs, and 
standards for communication among control devices--all of which could 
assist hackers in understanding the systems and how to attack them. 
Moreover, there are numerous former employees, vendors, support 
contractors, and other end users of the same equipment worldwide who 
have inside knowledge about the operation of control systems.

Security experts have stated that an individual with very little 
knowledge of control systems could gain unauthorized access to a 
control system using a port scanning tool and a factory manual that can 
be easily found on the Internet and that contains the system's default 
password. As noted in the following discussion, many times these 
default passwords are never changed.

Cyber Threats to Control Systems:

There is a general consensus--and increasing concern--among government 
officials and experts on control systems about potential cyber threats 
to the control systems that govern our critical infrastructures. As 
components of control systems increasingly make vital decisions that 
were once made by humans, the potential effect of a cyber attack 
becomes more devastating. Cyber threats could come from numerous 
sources ranging from hostile governments and terrorist groups to 
disgruntled employees and other malicious intruders. Based on 
interviews and discussions with representatives from throughout the 
electric power industry, the Information Assurance Task Force of the 
National Security Telecommunications Advisory Committee concluded that 
an organization with sufficient resources, such as a foreign 
intelligence service or a well-supported terrorist group, could conduct 
a structured attack on the electric power grid electronically, with a 
high degree of anonymity, and without having to set foot in the target 

In July 2002, NIPC reported that the potential for compound cyber and 
physical attacks, referred to as "swarming attacks," was an emerging 
threat to the critical infrastructure of the United States. As NIPC 
reports, the effects of a swarming attack include slowing or 
complicating the response to a physical attack. For instance, a cyber 
attack that disabled the water supply or the electrical system, in 
conjunction with a physical attack, could deny emergency services the 
necessary resources to manage the consequences of the physical attack-
-such as controlling fires, coordinating response, and generating 

According to the National Institute of Standards and Technology (NIST), 
cyber attacks on energy production and distribution systems--including 
electric, oil, gas, and water treatment, as well as on chemical plants 
containing potentially hazardous substances--could endanger public 
health and safety, damage the environment, and have serious financial 
implications such as loss of production, generation, or distribution by 
public utilities; compromise of proprietary information; or liability 
issues. When backups for damaged components are not readily available 
(e.g., extra-high-voltage transformers for the electric power grid), 
such damage could have a long-lasting effect. I will now discuss 
potential and reported cyber attacks on control systems, as well as 
challenges to securing them.

Control Systems Can Be Vulnerable to Cyber Attacks:

Entities or individuals with malicious intent might take one or more of 
the following actions to successfully attack control systems:

* disrupt the operation of control systems by delaying or blocking the 
flow of information through control networks, thereby denying 
availability of the networks to control system operators;

* make unauthorized changes to programmed instructions in PLCs, RTUs, 
or DCS controllers, change alarm thresholds, or issue unauthorized 
commands to control equipment that could potentially result in damage 
to equipment (if tolerances are exceeded), premature shutdown of 
processes (such as prematurely shutting down transmission lines), or 
even disabling control equipment;

* send false information to control system operators either to disguise 
unauthorized changes or to initiate inappropriate actions by system 

* modify the control system software, producing unpredictable results; 

* interfere with the operation of safety systems.

In addition, in control systems that cover a wide geographic area, the 
remote sites often are not staffed and may not be physically monitored. 
If such remote systems were to be physically breached, attackers could 
establish a cyber connection to the control network.

Department of Energy (DOE) and industry researchers have speculated on 
how the following potential attack scenario could affect control 
systems in the electricity sector. Using war dialers[Footnote 11] to 
find modems connected to the programmable circuit breakers of the 
electric power control system, hackers could crack passwords that 
control access to the circuit breakers and could change the control 
settings to cause local power outages and even damage equipment. A 
hacker could lower settings from, for example, 500 amperes[Footnote 12] 
to 200 on some circuit breakers; normal power usage would then 
activate, or "trip," the circuit breakers, taking those lines out of 
service and diverting power to neighboring lines. If, at the same time, 
the hacker raised the settings on these neighboring lines to 900 
amperes, circuit breakers would fail to trip at these high settings, 
and the diverted power would overload the lines and cause significant 
damage to transformers and other critical equipment. The damaged 
equipment would require major repairs that could result in lengthy 

Control system researchers at DOE's national laboratories have 
developed systems that demonstrate the feasibility of a cyber attack on 
a control system at an electric power substation where high-voltage 
electricity is transformed for local use. Using tools that are readily 
available on the Internet, they are able to modify output data from 
field sensors and take control of the PLC directly in order to change 
settings and create new output. These techniques could enable a hacker 
to cause an outage, thus incapacitating the substation.

Experts in the water industry consider control systems to be among the 
primary vulnerabilities of drinking water systems. A technologist from 
the water distribution sector has demonstrated how an intruder could 
hack into the communications channel between the control center of a 
water distribution pump station and its remote units, located at water 
storage and pumping facilities, to either block messages or send false 
commands to the remote units. Moreover, experts are concerned that 
terrorists could, for example, trigger a cyber attack to release 
harmful amounts of water treatment chemicals, such as chlorine, into 
the public's drinking water.

Cyber Attacks on Control Systems Have Been Reported:

Experts in control systems have verified numerous incidents that have 
affected control systems. Reported attacks include the following:

* In 1994, the computer system of the Salt River Project, a major water 
and electricity provider in Phoenix, Arizona, was breached.

* In March 1997, a teenager in Worcester, Massachusetts, remotely 
disabled part of the public switching network, disrupting telephone 
service for 600 residents and the fire department and causing a 
malfunction at the local airport.

* In the spring of 2000, a former employee of an Australian company 
that develops manufacturing software applied for a job with the local 
government, but was rejected. Over a 2-month period, the disgruntled 
rejected employee reportedly used a radio transmitter on as many as 46 
occasions to remotely hack into the controls of a sewage treatment 
system and ultimately release about 264,000 gallons of raw sewage into 
nearby rivers and parks.

* In the spring of 2001, hackers mounted an attack on systems that were 
part of a development network at the California Independent System 
Operator, a facility that is integral to the movement of electricity 
throughout the state.

* In August 2003, the Nuclear Regulatory Commission confirmed that in 
January 2003, the Microsoft SQL Server worm--otherwise known as 
Slammer--infected a private computer network at the Davis-Besse nuclear 
power plant in Oak Harbor, Ohio, disabling a safety monitoring system 
for nearly 5 hours. In addition, the plant's process computer failed, 
and it took about 6 hours for it to become available again. Slammer 
reportedly also affected communications on the control networks of at 
least five other utilities by propagating so quickly that control 
system traffic was blocked.

In addition, in 1997, the Department of Defense (DOD) undertook the 
first systematic exercise to determine the nation's and DOD's 
vulnerability to cyberwar. During a 2-week military exercise known as 
Eligible Receiver, staff from NSA used widely available tools to show 
how to penetrate the control systems that are associated with providers 
of electric power to DOD installations. Other assessments of control 
systems at DOD installations have demonstrated vulnerabilities and 
identified risks in the installations' network and operations.

Securing Control Systems Poses Significant Challenges:

The control systems community faces several challenges to securing 
control systems against cyber threats. These challenges include (1) the 
limitations of current security technologies in securing control 
systems, (2) the perception that securing control systems may not be 
economically justifiable, and (3) the conflicting priorities within 
organizations regarding the security of control systems.

Lack of Specialized Security Technologies for Control Systems:

According to industry experts, existing security technologies, as well 
as strong user authentication and patch management practices, are 
generally not implemented in control systems because control systems 
usually have limited processing capabilities, operate in real time, and 
are typically not designed with cybersecurity in mind.

Existing security technologies[Footnote 13] such as authorization, 
authentication, encryption, intrusion detection, and filtering of 
network traffic and communications, require more bandwidth, processing 
power, and memory than control system components typically have. 
Controller stations are generally designed to do specific tasks, and 
they often use low-cost, resource-constrained microprocessors. In fact, 
some control system devices still use the Intel 8088 processor, which 
was introduced in 1978. Consequently, it is difficult to install 
current security technologies without seriously degrading the 
performance of the control system.

For example, complex passwords and other strong password practices are 
not always used to prevent unauthorized access to control systems, in 
part because this could hinder a rapid response to safety procedures 
during an emergency. As a result, according to experts, weak passwords 
that are easy to guess, shared, and infrequently changed are reportedly 
common in control systems, including the use of default passwords or 
even no password at all.

In addition, although modern control systems are based on standard 
operating systems, they are typically customized to support control 
system applications. Consequently, vendor-provided software patches 
may be either incompatible with the customized version of the operating 
system or difficult to implement without compromising service by 
shutting down "always-on" systems or affecting interdependent 
operations. Another constraint on deploying patches is that support 
agreements with control system vendors often require the vendor's 
approval before the user can install patches. If a patch is installed 
in violation of the support agreement, the vendor will not take 
responsibility for potential impacts on the operations of the system. 
Moreover, because a control system vendor often requires that it be the 
sole provider of patches, if the vendor delays in providing patches, 
systems remain vulnerable without recourse.

Information security organizations have noted that a gap exists between 
currently available security technologies and the need for additional 
research and development to secure control systems. Research and 
development in a wide range of areas could lead to more effective 
technologies. For example, although technologies such as robust 
firewalls and strong authentication can be employed to better segment 
control systems from external networks, research and development could 
help to address the application of security technologies to the control 
systems themselves. Other areas that have been noted for possible 
research and development include identifying the types of security 
technologies needed for different control system applications, 
determining acceptable performance trade-offs, and recognizing attack 
patterns for use in intrusion detection systems.

Industry experts have identified challenges in migrating system 
components to newer technologies while maintaining uninterrupted 
operations. Upgrading all the components of a control system can be a 
lengthy process, and the enhanced security features of newly installed 
technologies--such as their ability to interpret encrypted messages--
may not be able to be fully utilized until all devices in the system 
have been replaced and the upgrade is complete.

Securing Control Systems May Not Be Perceived as Economically 

Experts and industry representatives have indicated that organizations 
may be reluctant to spend more money to secure control systems. 
Hardening the security of control systems would require industries to 
expend more resources, including acquiring more personnel, providing 
training for personnel, and potentially prematurely replacing current 
systems, which typically have a lifespan of about 20 years.

Several vendors suggested that since there have been no reports of 
significant disruptions caused by cyber attacks on U.S. control 
systems, industry representatives believe the threat of such an attack 
is low. While incidents have occurred, to date there is no formalized 
process for collecting and analyzing information about control systems 
incidents, thus further contributing to the skepticism of control 
systems vendors. We have previously recommended that the government 
work with the private sector to improve the quality and quantity of 
information being shared among industries and government about attacks 
on the nation's critical infrastructures.[Footnote 14]

Until industry users of control systems have a business case to justify 
why additional security is needed, there may be little market incentive 
for the private sector to develop and implement more secure control 
systems. We have previously reported that consideration of further 
federal government efforts is needed to provide appropriate incentives 
for nonfederal entities to enhance their efforts to implement CIP--
including protection of control systems. Without appropriate 
consideration of public policy tools, such as regulation, grants, and 
tax incentives, private-sector participation in sector-related CIP 
efforts may not reach its full potential.[Footnote 15]

Organizational Priorities Conflict:

Finally, several experts and industry representatives indicated that 
the responsibility for securing control systems typically includes two 
separate groups: (1) IT security personnel and (2) control system 
engineers and operators. IT security personnel tend to focus on 
securing enterprise systems, while control system engineers and 
operators tend to be more concerned with the reliable performance of 
their control systems. These experts indicate that, as a result, those 
two groups do not always fully understand each other's requirements and 
so may not effectively collaborate to implement secure control systems.

These conflicting priorities may perpetuate a lack of awareness of IT 
security strategies that could be deployed to mitigate the 
vulnerabilities of control systems without affecting their performance. 
Although research and development will be necessary to develop 
technologies to secure individual control system devices, existing IT 
security technologies and approaches could be implemented as part of a 
secure enterprise architecture to protect the perimeters of, and access 
to, control system networks. Existing IT security technologies include 
firewalls, intrusion-detection systems, encryption, authentication, 
and authorization. Approaches to IT security include segmenting control 
system networks and testing continuity plans to ensure safe and 
continued operation.

To reduce the vulnerabilities of its control system, officials from one 
company formed a team composed of IT staff, process control engineers, 
and manufacturing employees. This team worked collaboratively to 
research vulnerabilities and to test fixes and workarounds.

Efforts to Strengthen the Cybersecurity of Control Systems Under Way, 
but Lack Adequate Coordination:

Government, academia, and private industry have independently initiated 
multiple efforts and programs focused on some of the key areas that 
should be addressed to strengthen the cybersecurity of control systems. 
Our March 2004 report includes a detailed discussion of many 
initiatives. The key areas--and illustrative examples of ongoing 
efforts in these areas--include the following:

* Research and development of new security technologies to protect 
control systems. Both federal and nonfederal entities have initiated 
efforts to develop encryption methods for securing communications on 
control system networks and field devices. Moreover, DOE is planning to 
establish a National SCADA Test Bed to test control system 
vulnerabilities. However, funding constraints have delayed the 
implementation of the initial phases of these plans.

* Development of requirements and standards for control system 
security. Several entities are working to develop standards that 
increase the security of control systems. The North American Electric 
Reliability Council (NERC) is preparing to draft a standard that will 
include security requirements for control systems. In addition, the 
Process Controls Security Requirements Forum (PCSRF), established by 
NIST and NSA, is working to define a common set of information security 
requirements for control systems. However, according to NIST officials, 
reductions to fiscal year 2004 appropriations will delay these efforts.

* Increased awareness of security and sharing of information about the 
implementation of more secure architectures and existing security 
technologies. To promote awareness of control system vulnerabilities, 
DOE has created security programs, trained teams to conduct security 
reviews, and developed cybersecurity courses. The Instrumentation 
Systems and Automation Society has reported on the known state of the 
art of cybersecurity technologies as they are applied to the control 
systems environment, to clearly define what technologies can currently 
be deployed.

* Implementation of effective security management programs, including 
policies and guidance that consider control system security. Both 
federal and nonfederal entities have developed guidance to mitigate the 
security vulnerabilities of control systems. DOE's 21 Steps to Improve 
Cyber Security of SCADA Networks provides guidance for improving the 
security of control systems and establishing underlying management 
processes and policies to help organizations improve the security of 
control system networks.

In previous reports, we have recommended the development of a 
comprehensive and coordinated national plan to facilitate the federal 
government's CIP efforts. This plan should clearly delineate the roles 
and responsibilities of federal and nonfederal CIP entities, define 
interim objectives and milestones, set time frames for achieving 
objectives, and establish performance measures.

The President in his homeland security strategies and Congress in 
enacting the Homeland Security Act designated DHS as responsible for 
developing a comprehensive national infrastructure plan. The plan is 
expected to inform DHS on budgeting and planning for CIP activities and 
on how to use policy instruments to coordinate among government and 
private entities to raise the security of our national infrastructures 
to appropriate levels. According to Homeland Security Presidential 
Directive 7 (HSPD 7), issued December 17, 2003, DHS is to develop this 
formalized plan by December 2004.

In February 2003, the President's National Strategy to Secure 
Cyberspace established a role for DHS to coordinate with other 
government agencies and the private sector to improve the cybersecurity 
of control systems. DHS's assigned role includes:

* ensuring that there is broad awareness of the vulnerabilities in 
control systems and the consequences of exploiting these 

* developing best practices and new technologies to strengthen the 
security of control systems, and:

* identifying the nation's most critical control system sites and 
developing a prioritized plan for ensuring cyber security at those 

In addition, the President's strategy recommends that DHS work with the 
private sector to promote voluntary standards efforts and the creation 
of security policy for control systems.

DHS recently began to focus on the range of activities that are under 
way among the numerous entities that are working to address these 
areas. In October 2003, DHS's Science and Technology Directorate 
initiated a study to determine the current state of security of control 
systems. In December 2003, DHS established the Control Systems Section 
within the Protective Security Division of its Information Analysis and 
Infrastructure Protection (IAIP) Directorate. The objectives of this 
section are to identify computer-controlled systems that are vital to 
infrastructure functions, evaluate the potential threats to these 
systems, and develop strategies that mitigate the consequences of 
attacks. In addition, IAIP's National Cyber Security Division (NCSD) is 
planning to develop a methodology for conducting cyber assessments 
across all critical infrastructures, including control systems. The 
objectives of this effort include defining specific goals for the 
assessments and, based on their results, developing sector-specific 
recommendations to mitigate vulnerabilities. NCSD also plans to examine 
processes, technology, and available policy, procedures, and guidance. 
Because these efforts have only recently been initiated, DHS 
acknowledges that it has not yet developed a strategy for implementing 
the functions mentioned above.

As I previously mentioned, many government and nongovernment entities 
are spearheading various initiatives to address the challenge of 
implementing cybersecurity for the vital systems that operate our 
nation's critical infrastructures. While some coordination is 
occurring, both federal and nonfederal control systems experts have 
expressed their concern that these efforts are not being adequately 
coordinated among government agencies, the private sector, and 
standards-setting bodies. DHS's coordination of these efforts could 
accelerate the development and implementation of more secure systems to 
manage our critical infrastructures. In contrast, insufficient 
coordination could contribute to:

* delays in the general acceptance of security requirements and the 
adoption of successful practices for control systems,

* failure to address gaps in the research and development of 
technologies to better secure control systems,

* impediments to standards-creating efforts across industries that 
could lead to less expensive technological solutions, and:

* reduced opportunities for efficiency that could be gained by 
leveraging ongoing work.

In summary, it is clear that the systems that monitor and control the 
sensitive processes and physical functions of the nation's critical 
infrastructures are at increasing risk from threats of cyber attacks. 
Securing these systems poses significant challenges. Numerous federal 
agencies, critical infrastructure sectors, and standards-creating 
bodies are leading various initiatives to address these challenges. 
DHS's implementation of our recommendation--with which the department 
concurred--to develop and implement a strategy for better coordinating 
the cybersecurity of our critical infrastructures' control systems 
among government and private sector entities can accelerate progress in 
securing these critical systems. Additionally, implementing existing IT 
technologies and security approaches can strengthen the security of 
control systems. These approaches include establishing an effective 
security management program, building successive layers of defense 
mechanisms at strategic access points to the control system network, 
and developing and testing continuity plans to ensure safe operation in 
the event of a power outage or cyber attack.

Mr. Chairman, this concludes my statement. I would be pleased to answer 
any questions that you or other members of the Subcommittee may have at 
this time.

If you should have any questions about this statement, please contact 
me at (202) 512-3317 or Elizabeth Johnston, Assistant Director, at 
(202) 512-6345. We can also be reached by e-mail at and, respectively.

Other individuals who made key contributors to this testimony include 
Shannin Addison, Joanne Fiorino, Alison Jacobs, Anjalique Lawrence, and 
Tracy Pierson.


[1] Control systems are computer-based systems that are used by many 
infrastructures and industries to monitor and control sensitive 
processes and physical functions. Typically, control systems collect 
sensor measurements and operational data from the field, process and 
display this information, and relay control commands to local or remote 
equipment. There are two primary types of control systems. Distributed 
Control Systems (DCS) typically are used within a single processing or 
generating plant or over a small geographic area. Supervisory Control 
and Data Acquisition (SCADA) systems typically are used for large, 
geographically dispersed distribution operations.

[2] U.S. General Accounting Office, Critical Infrastructure Protection: 
Challenges and Efforts to Secure Control Systems, GAO-04-354 
(Washington, D.C.: March 15, 2004).

[3] Virus: a program that "infects" computer files, usually executable 
programs, by inserting a copy of itself into the file. These copies are 
usually executed when the "infected" file is loaded into memory, 
allowing the virus to infect other files. Unlike the computer worm, a 
virus requires human involvement (usually unwitting) to propagate. 
Trojan horse: a computer program that conceals harmful code. A Trojan 
horse usually masquerades as a useful program that a user would wish to 
execute. Worm: an independent computer program that reproduces by 
copying itself from one system to another across a network. Unlike 
computer viruses, worms do not require human involvement to propagate. 
Logic bomb: in programming, a form of sabotage in which a programmer 
inserts code that causes the program to perform a destructive action 
when some triggering event occurs, such as termination of the 
programmer's employment. Sniffer: synonymous with packet sniffer. A 
program that intercepts routed data and examines each packet in search 
of specified information, such as passwords transmitted in clear text.

[4] The CERT/CC is a center of Internet security expertise at the 
Software Engineering Institute, a federally funded research and 
development center operated by Carnegie Mellon University.

[5] Testimony of George J. Tenet, Director of Central Intelligence, 
before the Senate Select Committee on Intelligence, February 6, 2002.

[6] Symantec, Symantec Internet Security Threat Report: Trends for July 
1, 2003-December 31, 2003 (March 2004).

[7] Wi-Fi (short for wireless fidelity) is the popular term for a high-
frequency wireless local area network.

[8] President's Commission on Critical Infrastructure Protection, 
Critical Foundations: Protecting America's Infrastructures 
(Washington, D.C.: October 1997). 

[9] The National Research Council, Making the Nation Safer: the Role of 
Science and Technology in Countering Terrorism (Washington, D.C.: 
December 2002). 

[10] The White House, The National Strategy to Secure Cyberspace 
(Washington, D.C.: February 2003).

[11] War dialers are simple personal computer programs that dial 
consecutive phone numbers looking for modems.

[12] An ampere is a unit of measurement for electric current.

[13] See U.S. General Accounting Office, Information Security: 
Technologies to Secure Federal Systems, GAO-04-467 (Washington, D.C.: 
March 9, 2004) for a discussion of cybersecurity technologies.

[14] U.S. General Accounting Office, Critical Infrastructure 
Protection: Challenges for Selected Agencies and Industry Sectors, 
GAO-03-233 (Washington, D.C.: Feb. 28, 2003).

[15] U.S. General Accounting Office, Homeland Security: Information 
Sharing Responsibilities, Challenges, and Key Management Issues, 
GAO-03-1165T (Washington, D.C.: Sept. 17, 2003).