Colonial is an archetype of critical infrastructure.

Back in March, a hacking group known as DarkSide began a campaign on Colonial Pipeline’s IT network and billing systems. On May 7th, Colonial publicly announces the attack, shuts down servers and some pipelines and pays DarkSide $4.4M in ransom.  On May 12th, Colonial restores operations and announces fuel delivery timelines amidst panic buying at gas stations.

While Colonial was able to get operations back up and running after the 6-day shutdown, the incident’s economic ripple effects were stark.

  • Gas Stations: Last week, 71% of gas stations in North Carolina, 55% in Virginia, 54% in South Carolina and 49% in Georgia were dry.
  • Air Travel: American Airlines altered schedules and announced adding refueling stops for long-haul routes out of Charlotte, NC.
  • Department of Transportation: The DoT announced a regional state of emergency for 17 states, easing restrictions for transport of fuel.

Clearly, the closure of the 5,500-mile pipeline system has been the most disruptive cyberattack on record.

Colonial’s OT network uses automation systems to control and monitor the flow of fuel from refineries and tank farms into Colonial’s pipeline, and from Colonial’s pipeline into the tanks and transportation facilities belonging to suppliers and distributors.

According to CNN, people briefed on the matter were concerned they wouldn’t be able to figure out how much to bill customers, and the billing system is central to the unfettered operation of the pipeline.

The interdependency between the IT billing system and OT automation system is clear. Colonial automated fuel monitoring, and control data from the OT network is fed into the IT billing system so they know how much to bill customers.

The Problem – lack of proper access controls for critical systems

Colonial said it shut down the pipelines as a precaution to prevent the infection from spreading. The reality is that there are cascading dependencies when you automate processes and IT systems are dependent on OT systems and vice versa.  In addition to billing systems, Colonial’s IT network includes HR/payroll systems, supplier data, business analytics, pipeline schematics, etc… which are not interdependent on the pipeline automation system.

I don’t doubt that Colonial was taking a precautionary measure to “prevent spreading” – but this statement illuminates a bigger problem. Why would an attack on a critical billing system spread to other IT systems or the OT network? The likely answer is that this critical system was not properly segmented with separate logical access controls including multi-factor authentication and granular system or application authorization. There appears to be a lack of appreciation or recognition of the difference between a “critical” system and a “confidential” or “sensitive” system within Colonial’s IT operations.

IT systems that are interdependent on OT systems become critical infrastructure systems and must have separate logical access controls based on zero-trust. 

The Solution – Zero-Trust access platform for both critical IT and OT systems

While corporate IT networks must be connected to the internet, there are critical systems that need additional authentication and authorization. For example, it is no problem to give keys to the janitor to clean your office, but would you give him the combination to the safe under your desk? This is the concept of “zero-trust.”

For critical IT systems such as Colonial’s billing system, a zero-trust access layer including multi-factor authentication (MFA) and granular role and time-based authorization should be required. In addition, full user session logging, monitoring and recording of access to these systems is paramount.

The risk of ransomware is mitigated when a separate “zero-trust” user access layer is deployed between the “sensitive” corporate network and the “critical” billing systems.

There also needs to be a secure operational link between critical IT systems and OT network. This can be accomplished by additional segmentation, logging and monitoring.

The corporate IT network needs to have a separate zero-trust user access platform for connecting to the OT network. There may be OEMs that need access to control systems, and this access should also be controlled through MFA, user-to-asset connection control, logging, monitoring and recording.


Critical Infrastructure systems need to be identified in every large organization and measures need to be taken asap to ensure that the systems – whether on the IT network or OT network – are protected with a separate “zero-trust” user access platform.  A system housing credit card data is not critical infrastructure.  17,000 gas stations don’t run out of gas when a few hundred or thousand people need new credit cards.  We must understand relative risk and impacts and employ separate granular authentication and authorization to critical systems. We can mitigate risks from threat actors such as DarkSide as well as from other nefarious and skilled actors through a zero-trust methodology.