What is User-Based Access Control (UBAC)?
User-Based Access Control (UBAC) is a method of access management in which rights and access to systems are granted based on the identity of an individual user. In OT environments, UBAC ensures that employees, contractors or suppliers only get access to the systems and functions they need.
UBAC is a fundamental measure within Least Privilege and Zero Trust and is often applied in combination with Active Directory, RADIUS or 802.1X.
🧠 How does UBAC work?
- User identification
- Every person has a unique username or ID
- Authentication via password, badge or MFA (multi-factor authentication)
- Granting of rights
- Based on function, task, location or project
- For example: a maintenance technician may only read PLCs, not modify them
- Logging and auditing
- All activities are traceable to a specific user
- Supports Security Monitoring, SIEM, Incident Response
- Integration with access management
- UBAC is applicable to applications, networks, remote access and physical access
🏭 Application in OT networks
| Application | Example |
|---|---|
| SCADA platform | Only operator X may view trend data; engineer Y may configure |
| Remote Access | An external supplier gets only temporary access to one PLC |
| HMI | Login required for setpoint changes |
| Jump Server | Users can only reach their assigned system |
UBAC increases traceability and control in sensitive industrial networks.
🔐 UBAC vs. other access models
| Model | Characteristic |
|---|---|
| UBAC | Rights per user |
| RBAC (Role-Based Access Control) | Rights per function or role |
| ABAC (Attribute-Based Access Control) | Rights based on context (time, location, status) |
💡 UBAC can also be combined with RBAC or ABAC for fine-grained control.
✅ Benefits of UBAC
- Increased traceability and accountability
- Supports Least Privilege and Defense in Depth
- Easy to manage via Active Directory or GPOs
- Makes auditing and compliance with IEC 62443 and ISO 27001 easier
⚠️ Points of attention
- Administrative burden grows with many unique users
- Access rights must be reviewed regularly
- Misconfiguration risks over- or under-protection
📌 In summary
User-Based Access Control provides access management at the individual level and offers strong protection in OT environments. It forms the basis for responsible system use, detection of deviations and compliance with cybersecurity standards.