Ransomware attack forces 2-day shutdown of natural gas pipeline

Department of Homeland Security (DHS) on Tuesday said that an infection by an unidentified ransomware strain forced the shutdown of a natural-gas pipeline for two days.

For intunately, nothing blew up. The attacker never got control of the facility’s operations, the human-machine interfaces (HMIs) that read and control the facility’s operations were successfully yanked offline, and a geographically separate central control was able to keep an eye on operations, though it wasn’t instrumental in controlling them.

Where this all went down is a mystery.

The alert, issued by DHS’s Cybersecurity and Infrastructure Security Agency (CISA), didn’t say where the affected natural gas compression facility is located. It instead stuck to summarizing the attack and provided technical guidance for other critical infrastructure operators so they can gird themselves against similar attacks.

The alert did get fairly specific with the infection vector, though: whoever the attacker was, they launched a successful spearphishing attack, which enabled them to gain initial access to the facility’s IT network before pivoting to its operational technology (OT) network.

OT networks are where hardware and software for monitoring and/or controlling physical devices, processes and events reside. Some examples are SCADA industrial control systems, programmable logic controllers (PLCs), and HMIs.

After the attacker(s) got their hands on both the IT and OT networks, they deployed what CISA called “commodity” ransomware, encrypting data on both networks. Staff lost access to HMIs, data historians and polling servers. Data historians – sometimes referred to as process or operational historians – are used in several industries, and they do what you might expect: record and retrieve production and process data by time and store the information in a time series database.

Although humans partially lost their view of some low-level OT devices, the attack didn’t affect PLCs, and hence, the facility never lost control of operations.