Top 10 Cybersecurity Threats Facing OT Systems in 2025

Background: Evolving OT Cybersecurity Landscape

Operational Technology (OT) environments have undergone dramatic transformation over the past decade. Once air-gapped and isolated, today’s factories, energy plants, and infrastructures are deeply interconnected—powered by advanced automation, analytics, and the Industrial Internet of Things (IIoT). This digital convergence has enabled operational efficiency but introduced new, and often severe, cyber risks. In 2025, OT systems are not just at risk, they’re an explicit target. Ransomware gangs, nation-state actors, and hacktivists are launching highly sophisticated campaigns capable of disrupting physical processes, halting production, or endangering public safety.

What follows are the top 10 OT cybersecurity threats every industrial organization must understand and address this year.

1. Ransomware Targeting Industrial Operations

Ransomware attacks against OT and ICS surged an astonishing 87% year-over-year in 2024. Manufacturing and critical infrastructure remain prime targets as attackers recognize the costly operational downtime and leverage this for higher ransom demands. Attackers exploit flat networks and insecure remote access to move laterally from IT to OT.

2. Legacy Systems and Unpatched Vulnerabilities

Many OT systems run on legacy hardware and software that were never designed to withstand modern cyber threats. Outdated protocols, lack of encryption, and unsupported devices provide attackers with easy entry points, often compounded by weak or default credentials. Legacy assets remain operational due to high replacement costs, leaving critical processes open to compromise.

3. Expanding Attack Surfaces via IoT and Edge Devices

The adoption of industrial IoT (IIoT) has exponentially increased the attack surface. Connected sensors, cameras, and edge controllers often ship with insecure configurations, default passwords, unpatchable firmware, and scant security controls. Vulnerabilities in shared hardware or web management interfaces allow attackers to remotely take over process controllers or implant malware.

4. Insecure Remote Access

Work-from-anywhere models and the need for third-party support have popularized remote access tools in OT. However, over 65% of OT environments had insecure remote connection setups in 2024, commonly exposing critical assets to the internet without strong authentication or segmentation. Attackers actively scan for exposed protocols like SSH, often brute-forcing their way in using default credentials.

5. IT/OT Convergence and Lateral Movement

Digital transformation has erased the traditional boundaries between IT and OT. Compromised IT assets—phishing, malware, or credential theft, are leveraged to access OT networks, moving laterally to disrupt or manipulate industrial process controls. Cultural gaps between IT and OT teams often mean security controls are inconsistently applied.

6. Data Manipulation and “Living-Off-the-Land” Attacks

Attackers increasingly use legitimate system tools and scripts already present in the environment, so-called “living-off-the-land”, to persist, escalate privileges, and evade detection. Data manipulation is now the most common attack tactic in manufacturing, utilities, and transportation, far ahead of overt malware.

7. Sophisticated ICS Malware

Custom malware strains designed for industrial control systems, like Fuxnet and FrostyGoop, have proliferated. These toolkits can target specific programmable logic controllers (PLCs) and supervisory control and data acquisition (SCADA) systems to manipulate processes, cause equipment failures, or sabotage production. Detection remains challenging due to the stealthy nature and deep integration with OT protocols.

8. Cloud Integration Risks

OT systems are increasingly connected to cloud services for analytics and remote management. Misconfigurations, such as overly permissive cloud credentials or mismanaged APIs, can offer attackers a direct pathway into sensitive operational environments. The rapid shift to cloud has outpaced the adoption of secure architecture.

9. Supply Chain Attacks

Industrial organizations rely on complex supply chains involving numerous hardware, software, and service providers. Threat actors target these supply chains, injecting malicious code or compromising trusted vendors to gain a foothold inside the OT network. Recent incidents have shown how third-party risk can lead to catastrophic production outages.

10. Weaponized Social Engineering and AI Deception

Attackers are leveraging advanced social engineering, including deepfakes and spear-phishing, to trick OT staff into granting access or executing malicious actions. AI-powered automation now enables threat actors to craft highly convincing fake messages and voices, making it harder for even seasoned operators to spot deception.

Recommendations: Defending OT Systems in 2025

To protect OT and ICS environments in 2025, organizations should:

• Deploy asset discovery and monitoring tools for unified visibility.
• Segment OT from IT networks and enforce least-privilege, Zero Trust access.
• Harden devices by changing default passwords and enabling strong authentication.
• Apply virtual patching and network controls to protect legacy systems.
• Use behavioral monitoring and anomaly detection to uncover hidden threats.
• Intensify supply chain vetting and ensure contractual cybersecurity standards.
• Regularly train OT staff on social engineering and evolving attack tactics.