IAM policy binding in GCP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an IAM policy binding in Google Cloud?

An IAM policy binding connects a role to one or more members, defining who has what permissions on a resource.

beginner

What are the main components of an IAM policy binding?

The main components are:
1. Role - a set of permissions.
2. Members - users, groups, or service accounts.
3. Condition (optional) - a rule to limit when the binding applies.

beginner

How do you specify a member in an IAM policy binding?

Members are specified by their type and identity, for example:
- user:[e-mail]
- serviceAccount:[e-mail]
- group:[e-mail]

intermediate

What is the purpose of a condition in an IAM policy binding?

A condition limits when the binding applies, based on attributes like request time or resource properties, adding extra security control.

beginner

Why should you follow the principle of least privilege when creating IAM policy bindings?

To give only the minimum permissions needed, reducing the risk of accidental or malicious actions on your cloud resources.

What does an IAM policy binding connect in Google Cloud?

A A VM to a network

B A role to members

C A project to a billing account

D A storage bucket to a folder

An IAM policy binding connects a role (permissions) to members (users, groups, service accounts).

Which of the following is NOT a valid member type in an IAM policy binding?

A user:[e-mail]

B serviceAccount:[e-mail]

C device:device123

D group:[e-mail]

Device is not a valid member type; valid types include user, serviceAccount, group, and domain.

What is the role of a condition in an IAM policy binding?

A To limit when the binding applies

B To assign a role permanently

C To list all members

D To delete the binding

Conditions limit when the binding applies, adding extra control based on rules.

Which principle helps reduce risk when assigning IAM roles?

A Principle of least privilege

B Principle of maximum access

C Principle of open sharing

D Principle of unlimited roles

The principle of least privilege means giving only the permissions needed, reducing risk.

In an IAM policy binding, what does the 'role' represent?

A A billing account

B A user account

C A network location

D A set of permissions

A role is a collection of permissions that define what actions members can perform.

Explain what an IAM policy binding is and its main components.

Think about who gets what permissions and under what conditions.

Describe why using conditions in IAM policy bindings can improve security.

Consider how rules can restrict access based on time or resource attributes.

Practice

1. What does an IAM policy binding do in Google Cloud?

easy

A. It connects a role to one or more members to grant permissions.

B. It creates a new Google Cloud project.

C. It deletes user accounts from the organization.

D. It monitors network traffic between services.

Solution

1. Step 1: Understand IAM policy binding purpose

   An IAM policy binding links a role, which defines permissions, to members like users or service accounts.

2. Step 2: Identify correct function

   Only It connects a role to one or more members to grant permissions. describes this connection; other options describe unrelated actions.

3. Final Answer:

   It connects a role to one or more members to grant permissions. -> Option A

4. Quick Check:

   IAM binding = role + members [OK]

Hint: IAM binding links roles to members for permissions [OK]

Common Mistakes:

• Confusing IAM binding with project creation
• Thinking IAM binding deletes users
• Mixing IAM with network monitoring

2. Which of the following is the correct syntax snippet to bind a role to a user in a GCP IAM policy JSON?

easy

A. {"roles": "roles/viewer", "members": ["user:[e-mail]"]}

B. {"role": "roles/viewer", "member": "user:[e-mail]"}

C. {"role": "roles/viewer", "members": "user:[e-mail]"}

D. {"role": "roles/viewer", "members": ["user:[e-mail]"]}

Solution

1. Step 1: Check JSON key names

   The correct keys are 'role' and 'members'. 'members' must be a list even if one member.

2. Step 2: Validate member format

   Member must be inside a list with correct prefix like 'user:'. {"role": "roles/viewer", "members": ["user:[e-mail]"]} matches this exactly.

3. Final Answer:

   {"role": "roles/viewer", "members": ["user:[e-mail]"]} -> Option D

4. Quick Check:

   Role + members list = correct syntax [OK]

Hint: Members must be a list, even for one user [OK]

Common Mistakes:

• Using 'member' instead of 'members'
• Not using a list for members
• Swapping 'role' and 'roles' keys

3. Given this IAM policy snippet, which member has the 'roles/editor' role?

{
  "bindings": [
    {
      "role": "roles/viewer",
      "members": ["user:[e-mail]"]
    },
    {
      "role": "roles/editor",
      "members": ["serviceAccount:[e-mail]"]
    }
  ]
}

medium

A. user:[e-mail]

B. user:[e-mail]

C. serviceAccount:[e-mail]

D. group:[e-mail]

Solution

1. Step 1: Locate 'roles/editor' binding

   Look for the binding with role 'roles/editor' in the JSON; it has members list with one service account.

2. Step 2: Identify member with 'roles/editor'

   The member is 'serviceAccount:[e-mail]'. Other members have different roles.

3. Final Answer:

   serviceAccount:[e-mail] -> Option C

4. Quick Check:

   Editor role assigned to service account [OK]

Hint: Match role key to find correct member [OK]

Common Mistakes:

• Confusing roles/viewer with roles/editor
• Picking a member not listed under the role
• Ignoring service account prefix

4. You have this IAM policy JSON snippet:

{
  "bindings": [
    {
      "role": "roles/storage.admin",
      "members": "user:[e-mail]"
    }
  ]
}

What is wrong with this policy binding?

medium

A. The policy is missing a 'version' field.

B. The 'members' field should be a list, not a string.

C. The user email format is incorrect.

D. The 'role' field is misspelled.

Solution

1. Step 1: Check 'members' field type

   The 'members' field must be a list of strings, not a single string.

2. Step 2: Verify other fields

   'role' is correctly spelled, user email format is valid, and 'version' is optional.

3. Final Answer:

   The 'members' field should be a list, not a string. -> Option B

4. Quick Check:

   Members must be a list [OK]

Hint: Members always need square brackets [] [OK]

Common Mistakes:

• Using string instead of list for members
• Assuming 'version' is mandatory
• Mistaking email format as error

5. You want to grant the 'roles/logging.logWriter' role to all users in your organization except external users. Which IAM policy binding approach is best?

hard

A. Bind 'roles/logging.logWriter' to 'domain:yourcompany.com' member.

B. Bind 'roles/logging.logWriter' to 'allAuthenticatedUsers' member.

C. Bind 'roles/logging.logWriter' to 'allUsers' member.

D. Bind 'roles/logging.logWriter' to 'user:[e-mail]' member.

Solution

1. Step 1: Understand member types

   'allUsers' includes everyone, including external; 'allAuthenticatedUsers' includes any signed-in Google user; 'domain:' restricts to your company domain.

2. Step 2: Choose member to exclude external users

   Using 'domain:yourcompany.com' grants access only to users in your company domain, excluding external users.

3. Final Answer:

   Bind 'roles/logging.logWriter' to 'domain:yourcompany.com' member. -> Option A

4. Quick Check:

   Domain member limits to internal users [OK]

Hint: Use domain: to restrict to company users [OK]

Common Mistakes:

• Using allUsers exposes to everyone
• Using allAuthenticatedUsers includes external Google accounts
• Binding to single external user misses others