The CISA report, on 18 February, said a Windows ransomware attack had affected a natural gas compression facility run by an unnamed American pipeline operator. It was vague on other details.
Dragos said its claim was based on information that had been shared with it and public reporting. The founder of Dragos, Robert M. Lee, is a former NSA hacker, and the company specialises in security for industrial control systems.
The lack of segregation of IT and ICS environments, and the fact that both used Windows as the operating system, were the likely reasons why the pipeline had been breached, the Dragos post said.
The company added that the attackers had infiltrated a natural gas compression facility owned by the pipeline operator. The ICS devices affected included data historians and human machine interface devices. However, no Layer 1 devices or those lower down, such as programmable logic controllers, were affected.
After initially gaining access to the pipeline operator's network by using phishing, the attacker then pivoted and spread to ICS assets, Dragos said.
After that, ransomware was deployed across the network, disrupting operations. However, the attacker, though in a position to do a great deal of damage, did nothing apart from bringing about a controlled shutdown. Various ICS assets were disconnected and disabled.
In the case of the incident reported by the Coast Guard, it was mentioned that the Ryuk ransomware was employed to disrupt operations at a Maritime Transportation Security Act regulated facility.
Dragos cited the following common elements in the two reports to justify its conclusion that the two incidents were the same:
- "Initial infection via an email message containing a malicious link;
- "Primary operational impact through loss of view on Windows-based systems performing ICS-related operations; and
- "Relatively similar outage periods, with CISA reporting two days of downtime at the natural gas compression facility while the US Coast Guard reported an outage of over 30 hours."
The company said a number of factors meant it was confident enough to state that the incident did not represent a case of someone specifically targeting an industrial control system.
"This includes reportedly insufficient segregation between IT and ICS network environments within the victim organisation, ICS impacts only affecting Windows-based devices, and no available evidence indicating attackers tried to alter, modify, or degrade the integrity of ICS operations beyond encrypting Windows-based systems using 'commodity ransomware',” Dragos said.