The motive of financial and political gain — fueled partially by the ongoing conflict in Ukraine — has emboldened threat actors to barrage industrial control systems (ICS) with ever more disruptive cyberattacks, diversifying the threat landscape for critical infrastructure, new research shows.

This trend is expected to continue throughout 2023 with attackers arming themselves with new tactics and malware, forcing ICS operators to level up if they want to protect their networks, according to Nozomi Networks' "OT/IoT Security Report: A Deep Look Into the ICS Threat Landscape" for the second half of 2022, published Jan. 18.

It used to be that nation-state actors were the leading perpetrators of attacks against ICS, primarily using remote access Trojans (RATs) to drop malware payloads and gain remote access to networks, as well as mounting distributed denial-of-service (DDoS) attacks to cause "inconvenient" disruption, says Roya Gordon, security research evangelist at Nozomi Networks. "Historically, critical infrastructure disruptions were seen as a nation-state tactic," she says.

However, the now-infamous Colonial Pipeline attack in May 2021 marked a significant shift in this trend. In that incident, a ransomware attack that started with a stolen password caused panic and gas shortages across the eastern United States, and attackers realized how disruptive and potentially lucrative new attack vectors could be, she says.

"The Colonial Pipeline attack demonstrated how cybercriminals can leverage ransomware attacks on critical infrastructure — since they tend to depend heavily on real-time data, and have the means to meet ransom demands — for financial gain," Gordon notes.

Then with Russia's attack on Ukraine last February, attacks on ICS got political, with hacktivists, traditionally known for data breaches and DDoS attacks, wielding destructive wiper malware to disrupt transportation systems such as railroads and other critical infrastructure in the Ukraine for political gain, she says.

This marked a shift in not only who was attacking ICS, but how and for what motive they were launching these attacks, Gordon says. "All in all, this unprecedented level of activity across all fronts should cause us concern."

Top ICS Cyberattack Trends

The report identified top trends in the ICS threat landscape based on a compilation of information from various sources including open source media, CISA ICS-CERT advisories, and Nozomi Networks telemetry, as well as on exclusive IoT honeypots that Nozomi researchers employ for "a deeper insight into how adversaries are targeting OT and IoT, furthering the understanding of malicious botnets that attempt to access these systems," Gordon says.

What researchers observed over the last six months was a significant uptick in attacks that caused disruption to a number of industries, with transportation and healthcare being among the top new sectors finding themselves in the crosshairs of adversaries among more traditional targets.

Attackers are using various methods of initial entry to ICS networks, although some common weak security links that have historically plagued not just ICS but the entire enterprise IT sector — weak/cleartext passwords and weak encryption — continue to be the top access threats.

Still, “Root” and “admin” credentials are most often used as a way for threat actors to gain initial access and escalate privileges once in the network, the findings show. Other ways threat actors find their way in include brute-force attacks and DDoS attempts.

In terms of malware, RATs remain the most common malware detected against ICS, while DDoS malware and unusually high and still-rising IoT botnet activity continued to be the top threat for IoT devices on a network. The use of default credentials to hack IoT devices was the primary means of entry for IoT botnets, the researchers found.

Over the second half of last year, attacks on ICS spiked in July, October, and December, with more than 5,000 unique attacks in each of those months. Manufacturing and energy remained the most vulnerable industries, followed by water/wastewater, healthcare, and transportation systems.

Interestingly, despite the uptick in targeting Ukraine, the top attacker IP addresses observed in the second half of 2023 didn't come from Russia nor countries that side with Russia, the researchers found. Instead, the main IP addresses associated with ICS attacks were in China, the US, South Korea, and Taiwan, according to Nozomi's data.

The Look Ahead

Top among ICS/IoT threats to watch out for: adversaries will use hybrid threat tactics that don't follow what operators may have seen in the past, which means "it will become increasingly difficult to categorize types of threat actors based on TTPs and motives," according to the report.

Organizations in the healthcare sector — which saw a spike in attacks when COVID-19 hit that has continued even as the pandemic largely wanes — should be mindful to stay on top of medical-device updates, according to Nozomi. Threat actors will likely use exploits to access medical systems that aggregate device data, a manipulation that can have dire and even life-threatening consequences for patients, potentially leading to malfunctions, misreadings, or even overdoses in automatic release of medication.

Another new threat on the horizon is from AI-driven chatbots that attackers will use for malicious purposes, such as writing code or developing exploits for vulnerabilities. They also can use them to generate more accurate phishing/social engineering texts that can be used as entry access to ICS networks, the researchers said.

"All this could reduce the time it takes to develop targeted threat campaigns, thus increasing the frequency of cyberattacks," according to the report.

Though the news appears gloomy, securing ICS against oncoming threats can be as simple as practicing "basic cyber hygiene," employing typical IT security practices that any organization already should be using, Gordon says.

"While threat actors may have the capability to access OT and IoT directly, it's one of their long-standing strategies to first breach IT and pivot into OT," she says. "Therefore, taking steps to secure IT is key."