Iranian-linked groups are actively exploiting vulnerabilities in operational technology (OT) systems across US critical infrastructure, according to federal agencies. These actors are targeting internet-facing programmable logic controllers (PLCs) and misconfigured OT systems, gaining network access and enabling lateral movement. This exploitation allows potential disruption of critical infrastructure, posing a significant threat to national security. The warning comes amid rising geopolitical tensions, highlighting the need for increased vigilance. Specific technical details of the vulnerabilities being exploited have not been disclosed, but the threat is considered imminent. The Cybersecurity and Infrastructure Security Agency (CISA) has issued warnings to critical infrastructure operators to review their OT systems for potential exposure risks1. This threat matters to practitioners because it underscores the importance of securing OT systems against nation-state actors, who can cause significant disruption to critical infrastructure, highlighting the need for robust security measures to mitigate these risks.