How Shared Vendor Accounts in OT Put Uptime and Accountability at Risk

Why Shared Vendor Accounts Became the Default in OT Environments

In many manufacturing plants, shared vendor accounts aren’t seen as controversial. On the contrary, they’re a practical way to get key third-party specialists connected fast.

When a production line is down and a controls vendor needs remote access to a PLC, HMI, or other industrial control system, speed matters more than process. It might be late at night. The internal IT contact may not be immediately available or the vendor may rotate engineers frequently. Waiting for new credentials to be provisioned simply isn’t realistic when uptime, safety, and production targets are at stake.

So, using a shared vendor login becomes the default. And over time, shared accounts stop feeling temporary. They become embedded in how vendor remote access works across the OT environment because they solve a real problem: how to provide fast access to external partners without slowing production.

Shared accounts ensure that when something breaks, a technician or OEM can get in quickly. From an operations standpoint, the logic is clear: if the line is down, remove friction and restore output.

The challenge is that convenience and accountability rarely scale together. Shared vendor accounts work well during routine operations. Their limitations only appear later – during incidents, audits, or unexpected downtime – when visibility into who accessed what becomes vital.

Teams typically don’t come to depend on shared accounts because they’re being careless or willfully ignoring cybersecurity best practices. Shared accounts gain traction because traditional IT access control models don’t align with OT realities, especially in environments built on legacy industrial control systems.

This article explores the operational impact of shared vendor accounts in manufacturing and other OT environments, including:

• Why shared vendor accounts are so common in industrial control systems

• The hidden operational risks they create beyond basic cybersecurity concerns

• How shared credentials complicate root-cause analysis and incident response

• Why simply banning shared accounts often fails in real-world OT environments

• What a modern, accountable vendor remote access model should look like

• Practical steps plant managers and OT leaders can take to reduce risk without slowing production

After the Incident: When Shared Vendor Accounts Create Real Exposure

The real limitation of shared vendor accounts rarely shows up during routine operations. Instead, the consequences are felt during and after an incident.

Let’s look at just one example:  

A vendor connects remotely to resolve a production issue. The session appears successful, the immediate problem is addressed, and the line resumes operation. For the moment, everything is stable.

But then the next shift begins, and something doesn’t behave as expected. Parameters don’t align with documented settings. Equipment that ran the night before won’t restart cleanly. Production slows, and attention turns to what changed.

The access logs confirm that a shared vendor account accessed the OT system hours earlier –  but they don’t reveal is who logged in, where the connection originated, or exactly what actions were taken during the session.

When you reach out to the vendor, you discover that multiple engineers had access to the same credentials and had been supporting multiple facilities that week. No one can say with certainty who made the adjustment or whether any additional changes were made.

At this point, the situation stops being purely technical and becomes a question of accountability. Someone will ask what happened, who authorized the work, and how it led to downtime – and you won’t have clear answers.

For a plant manager or OT leader, this lack of traceability generates more than cybersecurity concern. It slows root-cause analysis, extends production downtime, and introduces uncertainty at the exact moment clarity is needed most.

Why Banning Shared Vendor Accounts Isn’t the Answer

Given the complications shared vendor accounts can create, it’s tempting to say, “just ban them.”

And on paper, that sounds straightforward. But in reality, it often creates more friction than it resolves — and can be surprisingly difficult to enforce.

Shared accounts didn’t become common by accident. They emerged because they solved a real operational problem. If the alternative requires manual account creation every time a vendor rotates engineers, support slows. If remote access approvals require multiple internal handoffs, emergency response times stretch. And when IT-centric access controls fail to reflect how maintenance and controls teams actually work, unofficial workarounds inevitably appear.

In industrial environments, production pressure is constant. Controls that introduce delays (especially during an outage) rarely last. Teams will find faster paths, even if they fall outside formal policy.

That’s why eliminating shared vendor accounts isn’t about imposing stricter rules. Any sustainable alternative must preserve what made shared access attractive in the first place: simplicity, speed, and reliability during critical moments.

If a new approach slows production, the workaround will almost certainly return.

What Vendor OT Access Should Look Like

Improving vendor remote access in manufacturing environments means introducing accountability without friction.

A more sustainble approach ties access to individual vendor identities rather than shared credentials, even if those identities are managed externally. Access is limited to the specific OT assets required for the task, instead of exposing large portions of the network. Sessions are time-bound by default and can be revoked immediately when work is complete.

Most importantly, visibility is built into the process. Plant and OT leaders can see – both in real-time and via session recordings – who connected, when they connected, and which systems were accessed.

And because industrial environments depend heavily on legacy systems, any workable access control model must integrate with existing older machines without requiring large-scale infrastructure upgrades or replacements.

When vendor remote access is both fast and accountable, it stops being a point of tension between IT and operations and becomes an operational safeguard.

How Accountable Vendor Access Improves Uptime and Operational Control

Moving away from shared vendor accounts isn’t about chasing cybersecurity maturity scores; it’s about strengthening operational control.

With clear, individual accountability, investigations move faster. Downtime following unexpected behavior is reduced because teams can quickly determine what changed. Audit conversations become straightforward rather than defensive. Internal friction between IT, operations, and third-party vendors decreases.

And perhaps most importantly, plant managers gain confidence that when senior leadership, regulators or customers ask what happened, they won’t have to rely on incomplete logs or assumptions. Instead, they'll have traceability and concrete answers.

A Practical Path Away from Shared Vendor Accounts

For plants that still rely heavily on shared vendor accounts, change doesn’t need to be disruptive.

The first step is a move toward visibility. Identify which vendors are using shared credentials to remotely access OT systems. From there, separate emergency access from routine maintenance workflows. Then, pilot individual, accountable access with one critical vendor before expanding further.

Shared accounts may remain temporarily as a controlled fallback, but they should no longer be the default. Incremental improvement is more sustainable than sweeping mandates.

When Convenience Becomes Operational Risk

Shared vendor accounts feel efficient because they remove friction at the moment of need. But when something goes awry, the absence of accountability ultimately creates even more friction.

In modern OT environments, secure vendor remote access is no longer just an IT concern. It directly impacts production uptime, audit readiness, and operational resilience.

When you can answer without hesitation, “Who accessed the system, what did they change, and how do we fix it?” — you’ve moved beyond convenience and into control. And in industrial operations, control is what keeps production moving.