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WGU D488 OBJECTIVE ASSESSMENT
Cybersecurity
Architecture &
Engineering
Comprehensive practice examination covering security
architecture principles, access control models,
cryptography, network security, cloud infrastructure,
application security, risk management, and endpoint
hardening aligned with 2026-2027 WGU curriculum
standards.
100 Questions with Answers & Rationales
Grade A Preparation Material
Latest Update
QU E S T I ONS A ND A NS W E R S W I T H C OMP R E H E NS I V E R AT I ONA L E S
,Section 1: Security Architecture and Design Principles (Q1-Q15)
Q1: A security architect is designing a system where no single individual can complete a critical
transaction alone. Which secure design principle is being applied?
A. Defense in depth
B. Separation of duties [CORRECT]
C. Least privilege
D. Economy of mechanism
Correct Answer: B
Rationale: Separation of duties divides critical tasks among multiple individuals so that no one person can complete a
sensitive operation alone, preventing internal fraud and errors. Defense in depth layers multiple security controls but does
not specifically address task division. Least privilege limits access rights but does not require multiple people for a task.
Economy of mechanism refers to keeping security designs simple to reduce attack surface.
Q2: Which security model focuses on preventing information disclosure by enforcing "no read up"
and "no write down" rules?
A. Biba
B. Clark-Wilson
C. Bell-LaPadula [CORRECT]
D. Brewer-Nash
Correct Answer: C
Rationale: The Bell-LaPadula model is a confidentiality-focused security model that uses two key rules: no read up (simple
security property, preventing subjects from reading objects at higher classification levels) and no write down (star property,
preventing subjects from writing data to lower classification levels). Biba focuses on integrity with the inverse rules.
Clark-Wilson uses well-formed transactions and separation of duties for integrity. Brewer-Nash addresses conflict of
interest.
Q3: An organization uses security labels such as Top Secret, Secret, and Confidential, and the system
enforces access based on these labels. Users cannot modify the labels. Which access control model is
this?
A. Discretionary Access Control (DAC)
B. Role-Based Access Control (RBAC)
C. Mandatory Access Control (MAC) [CORRECT]
D. Attribute-Based Access Control (ABAC)
Correct Answer: C
Rationale: Mandatory Access Control (MAC) uses system-enforced security labels (such as Top Secret, Secret, Confidential)
to control access. The system, not the user, determines access based on clearance levels and classifications, and users cannot
change these labels. This model is commonly used in government and military environments. DAC allows owners to
determine access. RBAC assigns access based on job roles. ABAC uses attributes like location, time, and department for
access decisions.
Q4: In threat modeling, which STRIDE category describes an attacker forging authentication
credentials to impersonate a legitimate user?
A. Tampering
WGU D488 Cybersecurity Architecture and Engineering Exam | Page 1
, B. Information Disclosure
C. Spoofing [CORRECT]
D. Elevation of Privilege
Correct Answer: C
Rationale: Spoofing in the STRIDE threat model refers to an attacker impersonating someone or something else by
falsifying authentication credentials. Tampering involves modifying data or code. Information Disclosure involves
exposing data to unauthorized parties. Elevation of Privilege involves gaining higher-level access than authorized. STRIDE
stands for Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege.
Q5: An organization is at CMMI Level 3: Defined. What does this level indicate about the
organization's processes?
A. Processes do not exist; the organization is reactive
B. Activities are defined but the organization is still reactive
C. The majority of work is defined and the organization is proactive [CORRECT]
D. Work is tracked and analyzed quantitatively
Correct Answer: C
Rationale: CMMI Level 3 (Defined) indicates that the majority of work processes are well defined and documented, and
the organization operates proactively rather than reactively. Level 1 (Initial) means processes are ad hoc and reactive. Level
2 (Managed) means basic activities are defined but the organization remains largely reactive. Level 4 (Quantitatively
Managed) adds statistical tracking and analysis of processes.
Q6: A security engineer applies the principle that a system should fail in a secure state rather than an
open state. Which secure design principle does this represent?
A. Fail secure [CORRECT]
B. Complete mediation
C. Open design
D. Least privilege
Correct Answer: A
Rationale: The fail secure principle ensures that when a system experiences a failure, it defaults to the most secure state
rather than leaving systems or data exposed. This is critical for security mechanisms such as firewalls, access control
systems, and encryption services. Complete mediation requires that every access request be checked. Open design means
security should not depend on secrecy of design. Least privilege ensures users have only the minimum access needed.
Q7: The Biba integrity model is most similar in structure to which confidentiality model, but with
reversed rules?
A. Clark-Wilson
B. Bell-LaPadula [CORRECT]
C. Brewer-Nash
D. Take-Grant
Correct Answer: B
Rationale: The Biba model is structurally similar to Bell-LaPadula but focuses on integrity rather than confidentiality. Biba
enforces "no read down" (preventing high-integrity subjects from reading low-integrity data) and "no write up" (preventing
low-integrity subjects from writing to high-integrity objects), which are the reverse of Bell-LaPadula's rules. Clark-Wilson
uses a different approach with well-formed transactions and separation of duties for integrity.
WGU D488 OBJECTIVE ASSESSMENT
Cybersecurity
Architecture &
Engineering
Comprehensive practice examination covering security
architecture principles, access control models,
cryptography, network security, cloud infrastructure,
application security, risk management, and endpoint
hardening aligned with 2026-2027 WGU curriculum
standards.
100 Questions with Answers & Rationales
Grade A Preparation Material
Latest Update
QU E S T I ONS A ND A NS W E R S W I T H C OMP R E H E NS I V E R AT I ONA L E S
,Section 1: Security Architecture and Design Principles (Q1-Q15)
Q1: A security architect is designing a system where no single individual can complete a critical
transaction alone. Which secure design principle is being applied?
A. Defense in depth
B. Separation of duties [CORRECT]
C. Least privilege
D. Economy of mechanism
Correct Answer: B
Rationale: Separation of duties divides critical tasks among multiple individuals so that no one person can complete a
sensitive operation alone, preventing internal fraud and errors. Defense in depth layers multiple security controls but does
not specifically address task division. Least privilege limits access rights but does not require multiple people for a task.
Economy of mechanism refers to keeping security designs simple to reduce attack surface.
Q2: Which security model focuses on preventing information disclosure by enforcing "no read up"
and "no write down" rules?
A. Biba
B. Clark-Wilson
C. Bell-LaPadula [CORRECT]
D. Brewer-Nash
Correct Answer: C
Rationale: The Bell-LaPadula model is a confidentiality-focused security model that uses two key rules: no read up (simple
security property, preventing subjects from reading objects at higher classification levels) and no write down (star property,
preventing subjects from writing data to lower classification levels). Biba focuses on integrity with the inverse rules.
Clark-Wilson uses well-formed transactions and separation of duties for integrity. Brewer-Nash addresses conflict of
interest.
Q3: An organization uses security labels such as Top Secret, Secret, and Confidential, and the system
enforces access based on these labels. Users cannot modify the labels. Which access control model is
this?
A. Discretionary Access Control (DAC)
B. Role-Based Access Control (RBAC)
C. Mandatory Access Control (MAC) [CORRECT]
D. Attribute-Based Access Control (ABAC)
Correct Answer: C
Rationale: Mandatory Access Control (MAC) uses system-enforced security labels (such as Top Secret, Secret, Confidential)
to control access. The system, not the user, determines access based on clearance levels and classifications, and users cannot
change these labels. This model is commonly used in government and military environments. DAC allows owners to
determine access. RBAC assigns access based on job roles. ABAC uses attributes like location, time, and department for
access decisions.
Q4: In threat modeling, which STRIDE category describes an attacker forging authentication
credentials to impersonate a legitimate user?
A. Tampering
WGU D488 Cybersecurity Architecture and Engineering Exam | Page 1
, B. Information Disclosure
C. Spoofing [CORRECT]
D. Elevation of Privilege
Correct Answer: C
Rationale: Spoofing in the STRIDE threat model refers to an attacker impersonating someone or something else by
falsifying authentication credentials. Tampering involves modifying data or code. Information Disclosure involves
exposing data to unauthorized parties. Elevation of Privilege involves gaining higher-level access than authorized. STRIDE
stands for Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege.
Q5: An organization is at CMMI Level 3: Defined. What does this level indicate about the
organization's processes?
A. Processes do not exist; the organization is reactive
B. Activities are defined but the organization is still reactive
C. The majority of work is defined and the organization is proactive [CORRECT]
D. Work is tracked and analyzed quantitatively
Correct Answer: C
Rationale: CMMI Level 3 (Defined) indicates that the majority of work processes are well defined and documented, and
the organization operates proactively rather than reactively. Level 1 (Initial) means processes are ad hoc and reactive. Level
2 (Managed) means basic activities are defined but the organization remains largely reactive. Level 4 (Quantitatively
Managed) adds statistical tracking and analysis of processes.
Q6: A security engineer applies the principle that a system should fail in a secure state rather than an
open state. Which secure design principle does this represent?
A. Fail secure [CORRECT]
B. Complete mediation
C. Open design
D. Least privilege
Correct Answer: A
Rationale: The fail secure principle ensures that when a system experiences a failure, it defaults to the most secure state
rather than leaving systems or data exposed. This is critical for security mechanisms such as firewalls, access control
systems, and encryption services. Complete mediation requires that every access request be checked. Open design means
security should not depend on secrecy of design. Least privilege ensures users have only the minimum access needed.
Q7: The Biba integrity model is most similar in structure to which confidentiality model, but with
reversed rules?
A. Clark-Wilson
B. Bell-LaPadula [CORRECT]
C. Brewer-Nash
D. Take-Grant
Correct Answer: B
Rationale: The Biba model is structurally similar to Bell-LaPadula but focuses on integrity rather than confidentiality. Biba
enforces "no read down" (preventing high-integrity subjects from reading low-integrity data) and "no write up" (preventing
low-integrity subjects from writing to high-integrity objects), which are the reverse of Bell-LaPadula's rules. Clark-Wilson
uses a different approach with well-formed transactions and separation of duties for integrity.
