Cybersecurity for Water and Wastewater Systems

Recent Events

In February, a hacker gained access to a chemical pump at a water treatment facility in Florida and attempted to increase the amount of sodium hydroxide in the water treatment process. An operator noticed the attack and was able to prevent any harm from happening. (Read more from CNN and NY Times and see EPA report below). And last fall, a ransomware attack at the University of Vermont Medical Center interrupted operations for months. (Read more from VT Digger).

These events show that even at water and wastewater systems, even in Vermont, it is important to be alert and take precautions to protect your digital infrastructure, from email to bill payment to SCADA. (Read more from the St Albans Messanger.)

Current Threat Analysis

On May 20, the US Department of Homeland Security (DHS) Office of Intelligence released an assessment stating that cyberattacks against water and wastewater systems are expected to increase in the United States and globally. The assessment said that cyber criminals may have the goal of receiving ransom payment or may be targeting the water sector in the context of a social/political conflict or ideological cause. Read the analysis here.

In addition, the Secretary of Homeland Security has issued a bulletin on the heightened threat of domestic terrorism in the United States. It does not mention threats specific to water or wastewater systems, but it is still a good idea to review your utility’s physical security and Emergency Response Plan. The bulletin is in effect through August 13, 2021. Read the bulletin here.

Learn about Cybersecurity

Cybersecurity means tacking action to guard your computer systems and data against unauthorized access that could result in theft, damage, or disruption of service. Potential damage caused by a cyberattack to a water or wastewater system includes lost productivity, operational disruption, the cost of ransom, the cost of repairing or installing new computer systems, theft of customer data, danger to public health or the environment, and loss of customer confidence.

Water Sector Cybersecurity Guide from EPA

15 Cybersecurity Fundamentals from WaterISAC

Cyber Safety Videos from CISA

Protect Your System

Here are some steps you can take on your own to protect your facilities. For the more complicated aspects of cybersecurity, we encourage you to contact CISA or EPA for free assistance (see next section).

  • Create an inventory of devices, software, networks, and the people who have access to them
  • Perform a cybersecurity risk assessment
  • Include cyberattacks in your Emergency Response Plan
  • Develop cybersecurity policies and procedures
  • Train all staff on cybersecurity practices
  • Ensure your system’s physical security prevents unauthorized access to devices
  • Learn to identify malicious emails
  • Use strong passwords and multi-factor authentication
  • Keep devices and software programs updated to the latest version
  • Back up critical data
  • Use network firewalls
  • Restrict all remote connections to SCADA systems
  • Turn off remote access software when not in use
  • Report suspicious activity of any kind to the Vermont Intelligence Center at 844-848-8477 or the anonymous online tip line
  • If your system is under attack, call 911 or CISA’s 24/7 report line at 888-282-0870

Free Assistance

The Cybersecurity and Infrastructure Security Agency (CISA)  is a branch of the Department of Homeland Security that assists the nation’s critical infrastructure with physical security and cybersecurity. CISA can perform an assessment of your system and advise you on steps you can take to improve your cybersecurity. These services are free, voluntary, and non-regulatory. Find more information at

In addition, EPA and the Horsley Witten Group are offering free cybersecurity assessments for some water and wastewater systems. They can also help you develop a cyber action plan. Find more information about this program here.

Cybersecurity Alert from EPA regarding Oldsmar Cyber Attack

On 5 February 2021, unidentified cyber actors obtained unauthorized access, on two separate occasions, approximately five hours apart, to the supervisory control and data acquisition (SCADA) system used at a local municipality’s water treatment plant. The unidentified actors accessed the SCADA system’s software and altered the amount of sodium hydroxide, a caustic chemical, used as part of the water treatment process. Water treatment plant personnel immediately noticed the change in dosing amounts and corrected the issue before the SCADA system’s software detected the manipulation and alarmed due to the unauthorized change. As a result, the water treatment process remained unaffected and continued to operate as normal.

The unidentified actors accessed the water treatment plant’s SCADA controls via remote access software, TeamViewer, which was installed on one of several computers the water treatment plant personnel used to conduct system status checks and to respond to alarms or any other issues that arose during the water treatment process. All computers used by water plant personnel were connected to the SCADA system and used the 32-bit version of the Windows 7 operating system. Further, all computers shared the same password for remote access and appeared to be connected directly to the Internet without any type of firewall protection installed.

Recommended Mitigation 

  • Restrict all remote connections to SCADA systems, specifically those that allow physical control and manipulation of devices within the SCADA network. One-way unidirectional monitoring devices are recommended to monitor SCADA systems remotely.
  • Install a firewall software/hardware appliance with logging and ensure it is turned on. The firewall should be secluded and not permitted to communicate with unauthorized sources.
  • Keep computers, devices, and applications, including SCADA/industrial control systems (ICS) software, patched and up-to-date.
  • Use two-factor authentication with strong passwords.
  • Only use secure networks and consider installing a virtual private network (VPN).
  • Implement an update and patch management cycle. Patch all systems for critical vulnerabilities, prioritizing timely patching of Internet-connected systems for known vulnerabilities and software processing Internet data, such as Web browsers, browser plugins, and document readers.

Last updated 5/28/21