Why User authentication and authorization in SCADA systems? - Purpose & Use Cases

The Big Idea

What if one wrong person could accidentally shut down your entire plant?

The Scenario

Imagine a SCADA system where every operator manually checks user IDs and passwords on paper before allowing access to control critical machines.

The Problem

This manual checking is slow, prone to mistakes, and can let unauthorized users slip in, risking safety and costly downtime.

The Solution

User authentication and authorization automate verifying who you are and what you can do, keeping the system safe and running smoothly without delays.

Before vs After

✗ Before

Check user ID on paper
Ask supervisor for approval
Allow or deny access

✓ After

Authenticate user with password
Check user role permissions
Grant or deny access automatically

What It Enables

It enables secure, fast, and reliable control over who can operate or change critical SCADA system functions.

Real Life Example

In a power plant, only authorized engineers can adjust turbine settings, preventing accidents and ensuring smooth energy production.

Key Takeaways

Manual user checks are slow and risky.

Authentication confirms identity automatically.

Authorization controls what each user can do safely.

Practice

1. What is the main purpose of user authentication in a SCADA system?

easy

A. To backup system data

B. To confirm the identity of a user

C. To monitor system performance

D. To control what actions a user can perform

Solution

1. Step 1: Understand authentication concept

   User authentication is about verifying who the user is.

2. Step 2: Differentiate from authorization

   Authorization controls permissions, not identity confirmation.

3. Final Answer:

   To confirm the identity of a user -> Option B

4. Quick Check:

   Authentication = Confirm identity [OK]

Hint: Authentication = Who you are, Authorization = What you can do [OK]

Common Mistakes:

• Confusing authentication with authorization
• Thinking authentication controls permissions
• Mixing system monitoring with user identity

2. Which of the following is the correct syntax to define a user role with read-only access in a SCADA system configuration file?

easy

A. role read_only { permissions: ["read"] }

B. role read_only = permissions: read

C. role: read_only { access = read }

D. read_only role { permissions = read }

Solution

1. Step 1: Identify correct role syntax

   The correct syntax uses 'role' keyword, role name, and permissions list in braces.

2. Step 2: Check option formats

   role read_only { permissions: ["read"] } correctly uses braces and array syntax for permissions.

3. Final Answer:

   role read_only { permissions: ["read"] } -> Option A

4. Quick Check:

   Correct role syntax uses braces and permission array [OK]

Hint: Look for braces and array syntax for permissions [OK]

Common Mistakes:

• Using '=' instead of ':' for permissions
• Missing braces around role definition
• Incorrect order of keywords

3. Given the following SCADA user permissions code snippet:

user = { name: "operator", roles: ["read_only", "control"] }
roles = {
  read_only: { permissions: ["read"] },
  control: { permissions: ["write", "execute"] }
}

What permissions does the user "operator" have?

medium

A. ["read"]

B. ["write", "execute"]

C. ["read", "write", "execute"]

D. ["read", "write"]

Solution

1. Step 1: Identify roles assigned to user

   User "operator" has roles "read_only" and "control".

2. Step 2: Combine permissions from both roles

   "read_only" grants ["read"], "control" grants ["write", "execute"]. Combined permissions are ["read", "write", "execute"].

3. Final Answer:

   ["read", "write", "execute"] -> Option C

4. Quick Check:

   Combine all role permissions for user [OK]

Hint: Add permissions from all user roles together [OK]

Common Mistakes:

• Selecting permissions from only one role
• Forgetting to merge permissions
• Confusing role names with permissions

4. A SCADA system admin tries to assign a user a role using this command:
assign_role user1 admin
But the system returns an error: "Role 'admin' not found." What is the most likely cause?

medium

A. The role 'admin' is not defined in the system

B. The user 'user1' does not exist

C. The command syntax is incorrect

D. The system is offline

Solution

1. Step 1: Analyze error message

   Error says "Role 'admin' not found," indicating the role is missing.

2. Step 2: Check command and user existence

   Command syntax looks correct and error does not mention user, so user likely exists.

3. Final Answer:

   The role 'admin' is not defined in the system -> Option A

4. Quick Check:

   Error message points to missing role [OK]

Hint: Check error message for missing role or user [OK]

Common Mistakes:

• Assuming user does not exist without checking
• Blaming command syntax without error details
• Ignoring error message content

5. In a SCADA system, you want to restrict a user so they can only read data but not control devices. Which approach best achieves this?

hard

A. Disable user authentication for faster access

B. Assign the user multiple roles including control

C. Grant the user admin privileges temporarily

D. Assign the user a role with only read permissions

Solution

1. Step 1: Understand requirement

   User must only read data, no control allowed.

2. Step 2: Choose role assignment

   Assigning a role with only read permissions restricts actions properly.

3. Step 3: Evaluate other options

   Assigning control roles or admin privileges contradicts restriction; disabling authentication is insecure.

4. Final Answer:

   Assign the user a role with only read permissions -> Option D

5. Quick Check:

   Restrict actions by role permissions [OK]

Hint: Use roles with minimal permissions to restrict users [OK]

Common Mistakes:

• Giving users more permissions than needed
• Disabling authentication to simplify access
• Using admin roles for normal users