A joint advisory attributed to the US Cybersecurity and Infrastructure Security Agency and the FBI describes ongoing activity linked to Iranian-aligned threat actors targeting operational technology environments in US critical infrastructure. The advisory states that internet-exposed industrial control components, including programmable logic controllers, have been actively probed and in some cases disrupted, with reported impacts including operational interruption and financial loss across multiple sectors.
The document focuses on risks to industrial environments where control systems are exposed to public networks, framing these systems as an expanded attack surface that can be leveraged when security boundaries are weak or absent.
Targeting of Industrial Systems
According to the advisory, the observed activity is directed at operational technology devices used to automate industrial processes. PLCs are identified as a primary focus, particularly models manufactured by Rockwell Automation under the Allen-Bradley brand, which are widely deployed across North American industrial systems.
The advisory also notes that other PLC families may be exposed to similar risk, including Siemens S7 devices used in various industrial environments globally. CISA describes the targeting as affecting systems used in sectors such as energy, water treatment, and other critical infrastructure environments where industrial automation is heavily relied upon.
Exposure of operational systems
CISA and FBI messaging emphasizes that a significant portion of the risk stems from direct internet exposure of industrial devices that are typically designed to operate within segmented or isolated networks. The advisory highlights that publicly accessible operational technology systems can create entry points for remote interaction, particularly when proper network segmentation and access controls are not implemented.
The report references the scale of infrastructure environments in the United States, including large numbers of drinking water and wastewater systems, as well as government and facility networks where industrial control components may be deployed.
Observed techniques
The advisory describes intrusion activity involving interaction with industrial project files and manipulation of human-machine interface (HMI) and supervisory control and data acquisition (SCADA) environments. It also states that overseas-based infrastructure was used in connection with access attempts, alongside leased third-party hosting services.
In some reported cases, attackers allegedly established remote access channels using secure shell tooling and standard network ports commonly associated with administrative access. The activity is described as targeting configuration software environments used to manage PLC programming and control logic.
Risk framing and broader context
CISA characterizes the issue as part of a broader pattern of industrial system exposure, particularly during periods of heightened geopolitical tension. The advisory suggests that publicly accessible OT devices remain a recurring target for capable threat actors, especially where security configurations allow direct connectivity to the internet.
The document also references previous incidents involving industrial systems, noting that PLC-related environments have been targeted in earlier campaigns affecting water and utility infrastructure. However, it does not present a definitive attribution of all activity to a single actor, instead framing findings as observed behavior linked to Iranian-aligned groups.
Mitigation guidance from CISA
The advisory recommends reducing or eliminating direct internet exposure of PLCs and related operational technology systems. It emphasizes the use of secure gateways, firewalls, and properly segmented network architectures to restrict external access to industrial environments.
It also advises monitoring system logs for unusual activity, particularly connections originating from unfamiliar or overseas hosting infrastructure. In addition, organizations are encouraged to review device configurations, ensure management interfaces are not publicly reachable, and apply available security guidance from manufacturers for affected PLC platforms.
Conclusion
The CISA and FBI advisory outlines continued attention on internet-facing industrial control systems, with a specific focus on PLC environments used in critical infrastructure sectors. While the report describes observed intrusion activity and associated disruptions, it frames the situation as an ongoing security concern tied to exposed operational technology systems rather than a single isolated campaign. The guidance centers on reducing exposure and tightening access controls across industrial environments to limit potential external interaction.
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