Security Architecture & Access Control Flashcards

Which security model enforces 'need-to-know' and least privilege principles?

Answer: Bell-LaPadula Model

The Bell-LaPadula Model is a state machine model of computer security that focuses on confidentiality. It enforces the "no read up" (Simple Security Property) and "no write down" (*-Property) rules, which are foundational to the 'need-to-know' and least privilege principles. This model ensures that subjects can only access information at or below their security clearance level and cannot write information to a lower security level, thereby protecting sensitive data from unauthorized disclosure.

What is the primary purpose of Role-Based Access Control (RBAC)?

Answer: To assign permissions based on job functions

Role-Based Access Control (RBAC) is an access control model that assigns permissions to users based on their specific roles or job functions within an organization. Instead of assigning permissions directly to individual users, permissions are grouped into roles, and users are then assigned to appropriate roles. This simplifies access management, ensures users only have the necessary access for their duties, and improves security by enforcing the principle of least privilege.

Which component of security architecture ensures systems can recover from failures?

Answer: Fault Tolerance

Fault tolerance is a design principle in security architecture that ensures a system can continue to operate without interruption even if one or more of its components fail. This is achieved by incorporating redundant hardware or software components. By having backup systems or components ready to take over, fault tolerance minimizes downtime and ensures business continuity in the event of a failure, thereby enhancing system reliability and resilience.

What does MAC (Mandatory Access Control) enforce?

Answer: System-enforced access based on labels

Mandatory Access Control (MAC) is a strict access control model where the operating system or security kernel enforces access decisions based on security labels assigned to subjects (users/processes) and objects (files/resources). Users cannot override these system-defined rules, making it highly secure and suitable for environments requiring stringent confidentiality, such as government or military systems. Access is granted only if the subject's security clearance level matches or exceeds the object's classification level.

Which protocol is used for centralized authentication in Windows environments?

Answer: Kerberos

Kerberos is a network authentication protocol that provides strong authentication for client/server applications by using secret-key cryptography. It is the default authentication protocol used in Microsoft Windows domains (Active Directory) to verify user and service identities. Kerberos prevents unauthorized access by ensuring that both the client and server are who they claim to be, using a trusted third party (Key Distribution Center).

What is the goal of the Biba Model?

Answer: To protect data integrity

The Biba Model is an access control model primarily concerned with protecting data integrity, preventing data from being corrupted or modified by unauthorized subjects. It enforces a "no write down, no read up" policy. This means a subject at a lower integrity level cannot write to an object at a higher integrity level, and a subject at a higher integrity level cannot read from an object at a lower integrity level, ensuring information flows only from lower to higher integrity levels.

Which access control method allows owners to set permissions?

Answer: Discretionary Access Control (DAC)

Discretionary Access Control (DAC) is an access control model where the owner of a resource (e.g., a file or folder) can grant or revoke access permissions to other users. This means the owner has discretion over who can access their resources and what actions they can perform. While flexible, DAC can be less secure than other models as it relies on individual users to manage permissions correctly, potentially leading to misconfigurations.

What is a 'zero-trust' architecture principle?

Answer: Never trust, always verify

The 'zero-trust' security model operates on the principle of "never trust, always verify," meaning no user, device, or application, whether inside or outside the network perimeter, is inherently trusted. Every access attempt must be authenticated, authorized, and continuously validated before granting access to resources. This approach significantly reduces the attack surface and limits the impact of potential breaches by assuming compromise and enforcing strict access controls.

Which standard provides guidelines for access control in ISO/IEC 27002?

Answer: ISO/IEC 27002

ISO/IEC 27002 is an international standard that provides a code of practice for information security controls, offering best practice recommendations for information security management. It includes a dedicated section (Control 9: Access Control) that outlines comprehensive guidelines for managing user access, authentication, and authorization to information systems and resources. While ISO/IEC 27001 is the management system standard, 27002 provides the detailed controls and implementation guidance.