Third-party access often becomes urgent at exactly the wrong moment. A software vendor needs to troubleshoot a failed application. An MSP has to work on a server after hours. A manufacturer needs remote access to a plant-floor workstation before production can resume.
The easy answer is to give the vendor a way in and sort out the details later. The safer answer is a defined vendor remote access process that controls who gets access, what they can reach, how long the connection lasts, and what evidence remains after the work is finished.
That distinction matters. The Verizon 2024 Data Breach Investigations Report found that 15% of breaches involved a third party.
For IT and security teams, the goal is not to eliminate vendor access. Many organizations could not operate effectively without it. The goal is to make each connection narrow enough to support the job without creating unnecessary access to the rest of the environment.
What Is Vendor Remote Access?
Vendor remote access is the process of allowing an outside supplier, contractor, MSP, or specialist to connect to approved company systems from another location.
The connection itself is only one part of that process.
A VPN can create a secure tunnel. A jump host can provide an intermediary between the vendor and a protected environment. Remote desktop software can let a technician work directly on an endpoint. None of those tools, by themselves, answer basic governance questions such as:
- Who approved this person?
- Which system are they allowed to use?
- Why do they need access?
- When should that access expire?
- What activity can the organization review later?
Those questions are what separate managed vendor access from simply handing an outside party credentials.
Vendor access also differs from normal employee remote access. An employee may require ongoing access to several company resources as part of a permanent role. A vendor usually needs something much narrower, such as two hours on one server to complete an upgrade or temporary access to an engineering workstation for troubleshooting.
That makes temporary, task-specific access a useful default.
How Vendor Access Controls Work
Think of vendor access as a sequence rather than a single security control.
First, the organization needs to know who is asking to connect. Then someone has to approve the request. The vendor receives access to the required resource, but not everything around it. Controls remain in place while the session is active, and access is removed when the work is complete.
Each step answers a different question.
| Control | What It Verifies or Restricts | Example | Evidence Produced |
|---|---|---|---|
| Individual identity | Connects activity to one person | Named vendor account | User record |
| MFA | Adds another identity check | Authenticator approval | Authentication event |
| Just-in-time approval | Restricts when access exists | Four-hour service window | Approval record |
| Segmentation | Restricts reachable resources | One server or subnet | Policy or network logs |
| Session logging or recording | Preserves connection activity | Session start, end, and actions | Audit trail |
The scope of access deserves particular attention. In the 2024 Identity Security Outlook, 77% of surveyed security leaders said their organizations had experienced an attack or breach related to improper access or overprivileged users during the previous 12 months.
CISA likewise recommends limiting third parties and MSPs to the devices and servers required by their roles instead of giving them unnecessary reach into the environment.
Authentication and Authorization
Authentication and authorization solve two different problems.
Authentication answers, “Is this really the person they claim to be?”
Authorization comes next: “What should that person actually be allowed to do?”
A vendor request might begin with a service ticket naming the target system, business reason, requested access window, requester, approver, vendor sponsor, and ticket number. Once approved, the vendor signs in through an individual account using MFA.
The individual-account requirement is important. If six technicians share one supplier login, a log may show that the account changed a configuration at 2:17 a.m. It will not necessarily show which technician did it.
Access should also end with the job. Just-in-time provisioning can grant the required permissions shortly before the approved work starts and remove them when that window closes.
For privileged work, PAM introduces another layer. Credential vaulting can keep an administrative password out of the vendor’s hands altogether. Instead of revealing a reusable password, the organization can broker the approved connection.
Session Restrictions and Accountability
Once a vendor is authenticated, the next concern is where that session can go.
Segmentation can prevent an approved connection to one server from becoming a route into unrelated systems. Jump hosts, virtual desktops, proxies, and controlled remote-session tools can also create a boundary between an unmanaged vendor device and the internal environment.
Not every session needs identical oversight.
A routine software update on a low-risk system may only require connection logs and a change record. A vendor modifying a production control system may justify active supervision or session recording.
Whatever level is chosen, the records should tie together the person, approved request, destination, timestamps, and relevant session activity.
RealVNC Connect security controls can support the remote-session portion of that model through capabilities such as MFA, granular permissions, end-to-end encryption, and session audit logging. The remote access layer still sits within the organization’s wider identity, approval, and privileged-access processes.
Vendor Access vs. VPN, PAM, and ZTNA
VPN, PAM, ZTNA, and remote-session technologies are sometimes treated as competing answers to the same problem. In practice, they often handle different parts of it.
| Approach | Primary Purpose | Typical Vendor Experience | Limitation if Used Alone |
|---|---|---|---|
| VPN | Provides encrypted network connectivity | Connects to an approved network segment | May provide more network reach than the task requires |
| ZTNA | Applies contextual access to specific resources | Requests access to an approved application or resource | Does not inherently provide a remote-support session |
| PAM | Controls privileged identities and credentials | Receives brokered or vaulted privileged access | Does not define the entire support workflow |
| Session-based access | Connects directly to an endpoint or desktop | Works inside a controlled remote session | May still require PAM or ZTNA for identity and privilege controls |
A VPN is not automatically unsafe. Its security depends on how it is configured and governed, including MFA, patching, segmentation, endpoint controls, monitoring, and the network scope made available after connection.
PAM addresses another concern: privileged credentials and elevated access. ZTNA moves the decision closer to the individual resource by evaluating identity and other context instead of treating network location as sufficient proof of trust.
Where the Approaches Overlap
A mature vendor-access design may use several of these controls together.
Consider a database vendor brought in to diagnose an issue. ZTNA might determine whether the technician can reach the required environment. PAM could broker the administrative credential. A controlled remote session could provide the actual workspace and produce an activity record.
That layered approach aligns with NIST zero trust guidance, which rejects the idea that a user or device should be trusted simply because of network location or ownership.
Legacy applications and OT equipment complicate matters because they may not support modern authentication or access policies themselves. A jump host or remote-session boundary can place modern controls in front of those systems.
The practical question stays the same regardless of architecture: can the organization establish who connected, what they accessed, why they were there, how long access existed, and what happened during the session?
High-Risk Vendor Access Scenarios
Some vendor requests deserve more scrutiny than others.
An emergency after-hours fix is one example. The pressure to restore service may be high, but that should not eliminate the ticket, approval, MFA, expiry time, or session record.
MSPs create a different challenge because one provider may support many locations or customer environments. Permissions should keep those environments separate so a technician working on one site does not automatically inherit access to another.
Industrial support can be more sensitive still. A manufacturer may need an equipment vendor to work on an HMI, PLC programming station, or engineering workstation. The session should be limited to the approved system, and changes capable of affecting production may require supervision.
Subcontractors also need explicit treatment. Access approved for one supplier should not quietly extend to another company simply because the primary vendor outsourced part of the work.
Finally, access removal needs to work in practice, not just on paper. A 2023 joint cybersecurity advisory described attackers using administrative credentials associated with a former contractor. Administrators should remove obsolete access promptly and verify that terminated accounts can no longer be used.
Vendor Access Across Industries
The systems change from one industry to another, but the basic access problem does not.
| Industry | Common Vendor Task | Sensitive Asset | Access Boundary |
|---|---|---|---|
| Manufacturing | PLC or MES support | HMI or engineering workstation | Approved device or production cell |
| Utilities and water | Control-system maintenance | SCADA, PLC, or telemetry system | Segmented OT environment |
| Regulated sectors | Specialist application support | System processing regulated data | Approved application or server |
A consistent request, approval, identity, and review process helps prevent every department or location from inventing its own method for bringing vendors into the network.
Industrial and OT Environments
Remote access in operational technology environments carries an additional constraint: a security change cannot come at the expense of safe, reliable operation.
NIST SP 800-82 Rev. 3 addresses those OT-specific concerns, including the different performance, reliability, and safety requirements found in industrial systems.
Organizations should avoid exposing industrial equipment directly to the public internet. A vendor can instead enter through a controlled boundary such as a VPN, jump host, or secure remote-session path and receive permission only for the relevant device.
Older industrial protocols can make that boundary particularly important. Protocols such as Modbus and DNP3 originated in environments where today’s internet-facing security assumptions did not apply.
The compromise of internet-facing Unitronics Vision Series PLCs illustrates the problem. CISA reported incidents involving devices protected by default passwords or no password and recommended removing public exposure and replacing default credentials.
NIST guidance and IEC 62443 provide useful reference points when organizations design segmentation, account management, and remote-access policies for OT environments. For a wider view of these controls on the plant floor, see our guide to secure remote access in manufacturing.
Regulated Sectors
For regulated organizations, granting access is only half of the job. The organization may also need to demonstrate that the access was authorized, appropriately limited, monitored where necessary, and terminated afterward.
A documented vendor access policy helps produce repeatable evidence for frameworks and audits, including work aligned with ISO/IEC 27001 and SOC 2 controls.
Contracts should also specify who may access systems, which systems are covered, security and notification obligations, and what happens when staff or supplier relationships change.
Whenever practical, routine technical support should be separated from access to sensitive data.
No remote-access product makes an organization compliant by itself. Compliance depends on the surrounding controls, contractual obligations, systems involved, jurisdiction, and how the organization applies its policies.
How Vendor Access Is Changing
The broad direction is toward less standing access.
Instead of maintaining vendor accounts that remain open indefinitely, organizations can increasingly make access dependent on a current request, approved resource, known identity, and defined time window.
That approach fits both zero trust principles and just-in-time access models.
It also matters in hybrid environments. The same supplier may need to support an on-premises application today and a cloud-hosted workload tomorrow. Another vendor may be responsible for legacy equipment that cannot participate directly in a modern identity architecture.
Consistent approval, expiry, and evidence rules help bridge those differences.
Automation can handle repeatable policy decisions, but exceptions still need human judgment. AI-driven security analytics and identity-provider platforms may contribute to the surrounding security stack, although those capabilities should not be confused with the remote-access function itself.
Security Risks of Vendor Access
Vendor risk rarely comes from one control failure in isolation. Problems tend to appear when credentials, connectivity, and excessive permissions overlap.
Common examples include:
- Compromised credentials: Reduce the impact with MFA, individual identities, and rapid revocation.
- Excessive privileges: Restrict vendors to the systems and actions required for the approved job.
- Exposed services: Minimize unnecessary internet exposure and keep supported access infrastructure patched.
- Shared accounts: Replace generic supplier credentials with accounts tied to named users.
- Missing audit evidence: Retain authentication, approval, and session records appropriate to the risk.
- Dormant access: Expire temporary permissions and review accounts when contracts or personnel change.
Verizon reported an approximately 180% year-over-year increase in vulnerability exploitation as an initial access step in its 2024 DBIR, with exploitation accounting for 14% of breaches.
Another useful signal comes from the Mandiant M-Trends 2024 report. Looking at investigations conducted during 2023, Mandiant found that 54% of organizations first learned about a compromise from an external source.
Good vendor-access controls cannot prevent every incident, but they can reduce unnecessary attack paths and leave investigators with better information when something goes wrong.
How to Implement Vendor Remote Access
The strongest programs turn vendor access into a repeatable operating process instead of handling each request as an exception.
- Inventory vendor connections. Identify suppliers, contractors, MSPs, subcontractors, applications, endpoints, and OT assets that currently require outside access. Give every relationship both a business owner and a technical owner.
- Define the access policy. Document approved connection methods, MFA requirements, permitted resources, supervision expectations, evidence retention, escalation procedures, and termination authority.
- Limit access by design. Apply least privilege and segmentation so vendors receive the systems required for their work rather than broad routes through the environment.
- Create approval and expiry workflows. Require a business reason and named approver before access begins. Use automatic expiry or just-in-time provisioning when the environment supports it.
- Keep useful evidence. Retain logs and consider supervision or recording for higher-risk work. The goal is to establish who connected, where they went, and when the session ended.
- Review and test revocation. Access reviews should reflect system criticality, privilege level, and organizational risk. Remove dormant identities and periodically confirm that administrators can end active vendor sessions when necessary.
Build a Controlled Vendor Access Program
Outside specialists are often essential. Permanent, poorly scoped access is not.
A practical vendor remote access program gives vendors enough access to finish the approved task while keeping identity, privilege, duration, and accountability under organizational control.
That may involve VPN connectivity in one environment, PAM and ZTNA in another, or a jump host and controlled remote session around a legacy system. The architecture can vary. The control objectives should not.
Start by finding vendor accounts and connections that already exist. Identify who owns them, what they are still used for, and whether their permissions match a current business need. Anything without a clear purpose deserves review.
Where a controlled remote-session layer is required, RealVNC Connect can support that part of the access model with encrypted sessions, MFA, permissions, and audit capabilities.
Frequently Asked Questions
How does vendor access work without a VPN?
Organizations can use ZTNA, browser-based portals, jump hosts, PAM-brokered connections, or remote-session tools to give a vendor access to a particular resource without placing the vendor’s device directly on the internal network. Authentication, MFA, approval, and least-privilege authorization still matter regardless of the connection method.
What is the difference between vendor access and PAM?
Vendor remote access covers the overall process for allowing and governing third-party connections. PAM focuses more specifically on privileged accounts, credentials, and elevated activity. The two are often used together when vendor work requires administrative rights.
Is a VPN safe for vendor access?
It can be. A VPN should be supported by MFA, current software, individual accounts, segmentation, least-privilege permissions, endpoint controls, time limits, and monitoring. The main concern is making sure a vendor does not receive more network access than the approved job requires.
How often should vendor access be reviewed?
There is no single interval that fits every environment. Review frequency should reflect the privilege involved, system criticality, vendor relationship, and the organization’s risk tolerance. Access should also be removed when work finishes or vendor personnel change rather than waiting for the next scheduled review.
Which frameworks address vendor access controls?
NIST guidance, ISO/IEC 27001, and SOC 2 include control areas relevant to third-party access, such as identity management, access control, logging, risk management, and periodic review. Organizations still need to map those controls to their own systems, contracts, regulatory obligations, and risk profile.
