Why does the convergence of IT and OT increase lateral movement risk in industrial networks?

Why IT and OT Convergence Creates More Paths for Lateral Movement

IT and OT convergence matters because it collapses boundaries that historically limited how far an attacker could travel after an initial foothold. When enterprise systems, engineering workstations, historians, remote access tools, and industrial controllers sit closer together, trust relationships multiply and segmentation becomes harder to reason about. NIST Cybersecurity Framework 2.0 is a useful lens here because it treats governance, asset visibility, and protective architecture as linked controls rather than separate concerns.

In industrial environments, lateral movement risk often rises not because one device is especially weak, but because the environment contains mixed trust levels, legacy protocols, and operational exceptions that were added for uptime. That combination gives an attacker more opportunities to reuse access, pivot through shared services, or abuse administrative pathways that were never designed for broad enterprise connectivity. In practice, many security teams discover this after remote access, vendor support, or flat network design has already created an unexpected bridge between business systems and control assets.

How Lateral Movement Happens Across Connected IT and OT Layers

Once IT and OT are interconnected, an attacker rarely needs a direct route to a controller or safety system. A more common path is to compromise a lower-friction IT asset first, then move through shared identity, remote administration, file transfer, monitoring, or engineering tooling until they reach systems with greater operational impact. The exact path depends on the environment, but the mechanism is consistent: every added trust edge can become a stepping stone.

Industrial networks often contain several features that make this easier. Windows-based engineering stations may share credentials or administration patterns with corporate endpoints. Remote support channels may bridge zones that were meant to stay separate. Legacy protocols can expose services without modern authentication. Even when the process is legitimate, the attacker may only need to inherit a trusted session, harvest credentials, or abuse an allowed management path to continue laterally.

• Shared identity and remote access can turn one compromise into several reachable systems.
• Flat or weakly segmented networks let discovery traffic become access to higher-value assets.
• Legacy OT devices may accept traffic that enterprise defenders cannot easily inspect or authenticate.
• Monitoring gaps matter because lateral movement often looks like normal maintenance activity until it is too late.

That is why zero trust concepts and strong identity governance are relevant even in industrial contexts. NIST SP 800-207 Zero Trust Architecture is especially useful when teams need to separate network location from access entitlement, while NIST SP 800-63 Digital Identity Guidelines helps frame stronger authentication for the identities that do traverse those boundaries. Where this guidance breaks down is in environments that cannot support segmentation or identity enforcement without disrupting essential operations, because the control design then has to be adapted to process constraints rather than applied as a generic IT pattern.

Where the Risk Is Highest in Mixed Industrial Environments

Tighter segmentation often increases operational overhead, so organisations have to balance resilience against maintainability and emergency access needs. That tradeoff becomes most visible in plants that rely on shared admin accounts, vendor connectivity, or aging assets that cannot be patched or reauthenticated in the same way as modern IT systems.

There are a few edge cases worth calling out. First, not every OT asset is equally exposed; systems isolated behind dedicated jump hosts or strict conduits are materially different from zones that share broad enterprise connectivity. Second, some industrial protocols are read-heavy and appear low risk, but read access can still support reconnaissance that precedes lateral movement. Third, converged environments sometimes use compensating controls such as allowlists or one-way gateways, but those controls only reduce risk if they are consistently enforced and monitored rather than assumed to be present.

Industry consensus is strong that visibility and segmentation matter, but there is less consensus on how much identity control can be pushed into older OT stacks without creating unacceptable operational fragility. For that reason, the real question is not whether convergence is “good” or “bad”; it is whether each connection has a clear business justification, a defined trust boundary, and a way to detect unexpected pivoting activity. MITRE ATT&CK Enterprise Matrix is helpful for thinking through how an attacker might chain discovery, credential access, and lateral movement across mixed environments, while NIST SP 800-53 Rev 5 Security and Privacy Controls provides a control vocabulary for access restriction, monitoring, and boundary protection. The guidance becomes less reliable when an organisation treats OT exceptions as permanent and unreviewed, because that is where hidden pathways tend to accumulate.

Practitioner Guidance

What to prioritise: Map the actual conduits between IT and OT before debating tool choices. The most valuable review is usually not asset inventory alone, but the small set of accounts, jump paths, and management channels that can reach both sides of the boundary.

What to verify: Verify that every cross-zone pathway has a business owner, an authentication requirement, and a revocation path. If a pathway exists only because it has “always been there,” treat it as an exposure until proven otherwise.

What practitioners underestimate: Lateral movement in industrial networks is often enabled by ordinary administration, not exotic exploitation. The deciding factor is usually whether maintenance convenience has quietly become standing trust across zones.

Practitioner takeaway: The safest converged environments are not the ones with the most controls, but the ones where every permitted bridge is narrowly justified, observable, and hard to reuse outside its intended purpose.

Related resources from NHI Mgmt Group

• Why do shared VPNs and jump boxes increase lateral movement risk in OT networks?
• Why do perimeter VPNs increase lateral movement risk in enterprise networks?
• Why do living off the land attacks in OT increase lateral movement risk so sharply?
• Why do trusted management protocols increase lateral movement risk in enterprise networks?