Introduction: The Access Problem No One Talks About, Until It's Too Late

In 2021, a water treatment facility in Oldsmar, Florida made international headlines. An unknown attacker remotely accessed the plant's systems and attempted to increase sodium hydroxide levels to a dangerously toxic concentration,111 times the normal level. The intrusion vector? Remote desktop access that was poorly secured, likely with shared credentials and no multi-factor authentication.

This wasn't a zero-day exploit. It wasn't a nation-state deploying custom malware. It was a privileged access failure.

In Operational Technology (OT) environments,where the physical and digital worlds converge, who has access to what, and under what conditions, is not just a cybersecurity concern. It is a matter of public safety, operational continuity, and national security.

Before we move forward, don’t forget to check out our previous post on “The digital fog of war: When Hacktivism goes pro” here 

Privileged Access Management in OT environments is one of the most critical,and most under implemented,security controls in industrial cybersecurity today. This guide breaks down what PAM is, why it's non-negotiable in ICS environments, and how to implement it strategically.

What Is Privileged Access Management in OT?

Defining Privileged Access

Privileged access refers to any account, credential, or session that grants elevated permissions beyond those of a standard user. In an IT environment, that might mean a domain administrator or a database root account. In an OT environment, the stakes are fundamentally different.

In OT, privileged accounts often control:

• Engineering Workstations (EWS)- Used to configure PLCs, RTUs, and SCADA systems

• HMI (Human-Machine Interface) terminals- Where operators interact directly with physical processes

• Remote access sessions- Used by vendors, integrators, and remote engineers to perform maintenance

• Network infrastructure accounts- Managing switches, firewalls, and data historians

These accounts, when misused, whether intentionally or through negligence, can disrupt operations, compromise safety systems, or hand attackers direct control over physical processes.

Privileged Access Management (PAM) is the discipline of managing, monitoring, and controlling these elevated access rights. It encompasses the policies, processes, and technologies that ensure privileged accounts are used only by the right people, at the right time, for the right reasons and that everything is recorded.

PAM vs. IAM: Understanding the Distinction

These two terms are often used interchangeably, but they are not the same, especially in OT.

Think of IAM as the gatekeeper for everyone entering the facility. PAM is the secure escort system for those who need access to the control room.

PAM vs. PAM Solutions

There's an important clarity to establish here: PAM is the security practice and framework. PAM solutions are the technology platforms that operationalize this practice,tools like CyberArk, BeyondTrust, Delinea, or purpose-built OT-native platforms.

A PAM solution without a mature PAM strategy will fail. A mature PAM strategy without the right tooling will struggle to scale. The two must be designed in tandem,especially in OT, where deployment complexity is significantly higher than in traditional IT environments.

Why PAM Is Critical for OT Environments

The OT Threat Landscape Has Fundamentally Shifted

For decades, OT systems operated in isolation, air-gapped from enterprise networks and the internet. Security through obscurity was the de facto model. That model is dead.

Today's industrial environments are deeply interconnected. The rise of Industrial IoT (IIoT), remote operations, cloud-connected SCADA, and digital twin technology has opened OT networks to the same threat actors that target enterprise IT, but with none of the mature security controls.

The Dragos 2024 OT Cybersecurity Report noted that threat groups specifically targeting industrial control systems have grown year-over-year, with a marked increase in groups that have developed the capability to disrupt or destroy industrial processes. And at the center of many of these attacks is one common denominator:compromised or abused privileged access.

The Insider Threat Is More Common Than You Think

In OT environments, insider threats are not just malicious employees, they are often:

• Contractors and system integrators who retain persistent access long after project completion

• Vendors who use shared credentials across multiple customer sites

• Operators who elevate their own privileges to"get the job done"faster

• IT administrators granted excessive rights in OT networks during IT/OT convergence projects

Without PAM, there is no visibility, no control, and no accountability for what any of these users do once they're inside.

Regulatory and Compliance Pressure Is Mounting

Frameworks like IEC 62443, NERC CIP, NIST SP 800-82, and the NIS2 Directive in Europe all emphasize access control and privilege management as foundational security controls.

Organizations in energy, water, manufacturing, and transportation that fail to implement robust access governance face both regulatory penalties and significantly elevated breach risk.

PAM is not just good practice,in regulated critical infrastructure sectors, it is rapidly becoming a compliance requirement.

Key Benefits of PAM in ICS/OT Environments

1. Dramatically Reduced Attack Surface

Every privileged account that exists without proper control is a potential attack vector. PAM reduces the attack surface by:

• Eliminatingshared,staticpasswordsonOTdevices

• Enforcingtime-limited,session-specificcredentials

• Removingpersistentaccessinfavourofjust-in-timeprovisioning 

When an attacker compromises one credential, PAM ensures that the credential has minimal scope and minimal duration, dramatically limiting lateral movement.

2.  Insider Threat Mitigation

Session monitoring and recording mean that every action taken by a privileged user, whether an engineer, vendor, or administrator, is captured and reviewable. This creates both a deterrent effect and a forensic record that is invaluable in incident response.

3.  Compliance and Audit Readiness

PAM solutions generate detailed audit trails automatically. When a NERC CIP or IEC 62443 audit occurs, the evidence is already compiled, including  who accessed what system, when, from where, and what actions were taken. This reduces audit preparation time and strengthens compliance posture.

4.   Secure Remote and Vendor Access

Remote access is one of the highest-risk vectors in OT security. PAM enables organizations to:

• Grant vendors time-bounded,system-specific access, not blanket network access.

• Require MFA before any session is established.

• Record every remote session in full.

• Terminate sessions instantly if suspicious activity is detected.

This transforms vendor access from an uncontrolled liability into a governed, auditable process.

How PAM Prevents Cyberattacks: Real-World Context

The Colonial Pipeline Breach

In May 2021, Colonial Pipeline,  operator of the largest fuel pipeline in the United States, suffered a ransomware attack that forced a shutdown of operations across the Eastern Seaboard. The entry point? A compromised VPN account with no MFA, connected to a legacy remote access system. The credential was reportedly found in a batch of leaked passwords on the dark web.

A properly implemented PAM solution would have:

• Vaulted and rotated that credential automatically.

• Required MFA for any privileged session.

• Flagged the unusual login time and origin as anomalous.

• Provided a session recording for immediate forensic analysis.

Triton/TRISIS Malware: The Safety System Threat

In 2017, attackers deployed the Triton/TRISIS malware against a petrochemical facility in Saudi Arabia, specifically targeting Safety Instrumented Systems (SIS). The attack required the adversaries to gain access to engineering workstations with direct connectivity to the Triconex safety controllers.

This level of access, deep inside the OT network, on engineering systems,is exactly what PAM is designed to govern. Lateral movement was possible because privileges were not properly segmented or monitored.

Core Features of PAM Solutions for OT

Credential Vaulting

Credential vaulting stores privileged account passwords in an encrypted, centralized vault. In OT environments, this means:

• PLC and RTU passwords are no longer stored in spreadsheets or Post-it notes on control panels.

• Crdentials are checked out for specific sessions and automatically rotated afterward.

• Default manufacturer passwords, a persistent plague in OT, are eliminated.

Least Privilege Enforcement

The principle of least privilege dictates that every user, process, and system should have only the minimum access required to perform its function,nothing more.

In OT, this is operationally complex because many legacy systems run services under administrative accounts by default. PAM solutions help map and right-size these privileges, reducing the blast radius of any compromise.

Session Monitoring

Real-time session monitoring allows security teams to observe active privileged sessions as they occur. In OT environments, this is critical because:

• Anomalous commands (e.g., a vendor modifying PLC logic outside of a maintenance window) can be detected and terminated immediately.

• Behavioral baselines can be established for each user and role.

• Integration with OT-aware SIEM or SOC platforms enables automated alerting.

Session Recording

Session recording captures a full audit trail,keystrokes, commands, mouse movements, and screen activity,for every privileged session. This is not just a compliance feature; it is a forensic asset.

When an incident occurs in an OT environment, the ability to replay exactly what happened on an engineering workstation or remote vendor session is invaluable. It compresses investigation timelines from weeks to hours.

What Is Session Recording and Why Does It Matter in OT?

Session recording in OT PAM works by intercepting privileged sessions at the protocol level, whether via RDP, SSH, web-based HMI interfaces, or vendor-specific protocols, and capturing a searchable, time-stamped record of all activity.

In OT, this matters for several reasons unique to industrial environments:

Process Safety Accountability: If a configuration change to a DCS or PLC triggers an unplanned shutdown or equipment fault, session recordings provide a definitive record of what was changed, by whom, and when. This is essential for root cause analysis (RCA) and preventing recurrence.

Vendor Accountability: When a third-party OEM engineer remotely accesses your assets, you are trusting their security posture as much as your own. Session recording ensures that trust is backed by evidence,not assumption.

Regulatory Evidence: Regulators increasingly require documented evidence of access control. A session recording is the strongest form of that evidence.

Implementing PAM in OT Environments: Challenges and Strategy

Can PAM Be Easily Implemented in OT?

Candidly,no. OT PAM implementation is significantly more challenging than IT PAM, and organizations that underestimate this complexity face failed deployments and frustrated operations teams.

The reasons are structural:

• Legacy Systems: Many OT devices run proprietary operating systems or firmware that predate modern authentication standards. Some cannot support agents or API integrations.

• DowntimeSensitivity: In a running plant, you cannot simply push an update or reboota controller to install PAMagents. Maintenance windows are narrow and often months apart.

• Air-GapandNetworkSegmentation: PAM solutions require connectivity to function. Heavily segmented OT networks may require careful architectural design to avoid creating new security gaps while enabling PAM functionality.

• OperationalCulture: Engineers who haveworkedwithstatic, sharedpasswords for years oftenresist PAM as operational overhead. Change management is as importantas technology.

Key Factors to Evaluate Before Selecting a PAM Solution for OT

OT Protocol Awareness: Does the solution understand OT protocols like Modbus, DNP3, EtherNet/IP, or OPC-UA? Can it provide meaningful context for sessions using these protocols, not just generic network traffic?

Agentless Architecture Options: Legacy PLCs and RTUs cannot support software agents. A PAM solution for OT must offer agentless deployment options for legacy assets.

Integration with OT Security Ecosystem: Can it integrate with your OT SIEM, industrial firewall, or asset inventory platform? PAM should amplify your existing security stack, not operate in isolation.

Operational Resilience: What happens to access if the PAM solution itself goes offline? A well- designed OT PAM deployment must include break-glass procedures that maintain operational continuity without bypassing security entirely.

Steps to Implement PAM in OT Environments

Step 1 - Asset Discovery and Privilege Mapping

You cannot protect what you cannot see. Begin with a comprehensive OT asset inventory, every PLC, RTU, HMI, engineering workstation, historian, and network device. For each asset, map:

• All accounts that exist (local, domain, service accounts)

• Current privilege levels

• Who uses them and for what purpose

• How credentials are currently managed

This phase often reveals shocking gaps: shared accounts used by dozens of vendors, default manufacturer credentials still active years after deployment, and administrator accounts used for routine operations.

Step 2- Tiered Privilege Classification

Classify all privileged accounts by risk level. A vendor connecting to a non-critical historian sits in a different risk tier than an engineer with write access to a safety PLC. Tiering informs policy design and helps prioritize vaulting and monitoring rollout.

Step 3- Policy Design and Enforcement

Define access policies that reflect OT operational reality:

• Standard maintenance windows vs. emergency access protocols

• Vendor-specific access constraints (time, system scope, required approvals)

• Escalation procedures for just-in-time access requests

Policies must be developed in collaboration with operations and engineering teams, not imposed by IT or security in isolation.

Step 4- Phased Deployment

Start with highest-risk assets and remote access vectors. Do not attempt a facility-wide rollout simultaneously. A phased approach allows the security team to learn the operational environment, refine policies, and build trust with plant personnel before expanding

Step 5- Continuous Monitoring and Auditing

PAM is not a set-and-forget deployment. Continuous monitoring of privileged sessions, regular review of access entitlements, and periodic red-team exercises against the PAM architecture are essential to maintaining effectiveness over time.

Privileged Access Management Best Practices for OT

Enforce the Least Privilege Principle, Rigorously

In OT, least privilege is not just about user accounts. It applies to service accounts, application accounts, and inter-system communication. Every connection between a historian and an enterprise ERP, every scheduled script that reads from a SCADA database,all should operate under the minimum privilege necessary.

Implement Just-in-Time (JIT) Access

JIT access eliminates standing privileges entirely. Instead of an engineer having persistent administrator rights on an engineering workstation, they request elevated access for a specific task, for a specific duration, with specific justification. When the task is complete, access is revoked automatically.

In OT environments where maintenance activities are discrete and predictable, JIT access dramatically reduces the window of opportunity for attackers.

Require Multi-Factor Authentication for Every Privileged Session

No privileged session, remote or on-site, should be possible with a single credential factor. MFA is the single most effective control against credential-based attacks. Even if a credential is compromised, MFA prevents its use.

Monitor Continuously, Not Periodically

OT security teams often review access logs reactively, after an incident. True security requires continuous behavioural monitoring with real-time alerting. Establish behavioural baselines for each privileged account and flag deviations automatically.

Conduct Regular Privileged Access Reviews

Access entitlements accumulate over time. Vendors complete projects and their access lingers. Employees change roles. Systems are decommissioned but their accounts remain. Quarterly access reviews, where every privileged account is validated against a current business need, are essential hygiene in OT environments.

Advanced Use Cases: PAM Beyond the Basics

Effective Discovery and Hardening

PAM solutions with integrated discovery capabilities can continuously scan OT networks for new or unmanaged privileged accounts, flagging shadow accounts created during system updates or by third-party tools. This ongoing discovery feeds into a hardening cycle that progressively eliminates attack surface.

Secure Elevated Access for Engineers and OEMs

When an OEM vendor needs to perform a firmware update on a critical asset, PAM enables a structured process:

• Vendor submits an access request with justification, system scope, and time window

• A plant security officer approves the request

• JIT credentials are generated and delivered through the PAM vault

• The session is monitored in real time and recorded in full

• Access expires automatically at session end

This is a dramatic improvement over the industry norm of emailing static VPN credentials to a vendor and hoping for the best.

PAM in Remote Access Architecture

Remote access is the highest-risk vector in OT security today. A robust PAM implementation should sit at the center of your remote access architecture, not as an afterthought, but as the primary control plane. Every remote connection into the OT environment should flow through the PAM solution, regardless of whether the user is an internal engineer working from home or a vendor in another country.

This requires integration with your secure remote access gateway, whether that's a purpose-built OT remote access platform or a hardened jump server architecture.

Strategic Recommendations for CISOs and OT Security Leaders

1. Treat PAM as an OT-Specific Initiative, Not an IT Handoff

IT-centric PAM deployments often fail in OT because they don't account for operational constraints. Build your OT PAM program with OT engineers at the table from day one.

2. Prioritize Vendor Access First

Third-party remote access is your highest-risk, lowest-controlled vector. Starting PAM implementation with vendor access governance delivers the highest security ROI in the shortest time.

3. Align PAM with Your IEC 62443 or NERC CIP Program

Map PAM controls to the specific access management requirements in your applicable framework. This ensures that your PAM investment directly contributes to compliance posture and satisfies auditor requirements.

4. Invest in OT-Aware PAM- Not a Repurposed IT Tool

The PAM solution you choose must understand OT operational realities: proprietary protocols, legacy systems, operational uptime requirements, and the safety implications of access decisions. A generic enterprise PAM solution retrofitted for OT will create friction and gaps.

Conclusion: Securing the Future of Industrial Operations

The convergence of IT and OT has brought massive operational benefits, but it has irreversibly changed the threat landscape. Relying on shared passwords and unmonitored VPNs is no longer just a cybersecurity risk; it is an existential business risk.

Implementing Privileged Access Management in OT is the most effective way to regain control over your critical infrastructure. By locking down credentials, enforcing least privilege, and recording every administrative session, you transform your industrial network from a soft target into a hardened, resilient environment.

Ready to secure your critical infrastructure? At Shieldworkz, we specialize in bridging the gap between operational reality and advanced cybersecurity. Contact our experts today to assess your OT access risks and design a PAM strategy that protects your systems, your people, and your bottom line.

Additional resources    

2026 OT Cybersecurity Threat Landscape Analysis Report here 
A downloadable report on the Stryker cyber incident here      
Remediation Guides here    
IEC 62443 and NIS2 Compliance Checklist here 
OT Security Best Practices and Risk Assessment Guidance here