ISC Practice Test 16 — 15 Questions

Question 1

An ISSEP is evaluating the security of an OT/ICS environment. Which THREE of the following are considered high-priority mitigation strategies to protect against common ICS cyber threats?

Accepted Answer

Implementing unidirectional gateways (data diodes) to isolate the control network.. ICS security focuses on availability and integrity, requiring physical segmentation, secure remote access, and protecting the PLC/DCS controllers themselves from direct interference.

Answer

Replacing all legacy controllers with cloud-based instances.

Answer

Deploying standard IT-based patch management tools directly on all PLCs.

Question 2

You are evaluating the risk of an Artificial Intelligence (AI) model deployment. The model is susceptible to 'model inversion' attacks, where an attacker can reconstruct sensitive training data. What is the most effective engineering control to prevent this?

Accepted Answer

Apply differential privacy techniques to the training process.. Model inversion attacks reconstruct sensitive training data by querying the model and analyzing its outputs, exploiting the model's tendency to memorize and leak information about its training set. Differential privacy adds calibrated noise during training so that the model's outputs are statistically indistinguishable whether or not any single individual's data was included, directly preventing reconstruction of specific training records. This is the most effective engineering control because it addresses the root cause — information leakage through model parameters.

Answer

Encrypt the model weights at rest.

Answer

Implement rate limiting on the model's API.

Answer

Retrain the model on a smaller, obfuscated dataset.

Question 3

You are assessing an Engineered System that uses a micro-segmentation strategy to isolate workloads. An attacker has compromised a single container and is attempting to perform network reconnaissance. What mechanism should block this attempt?

Accepted Answer

Zero-trust network policies that enforce default-deny communication between containers.. Micro-segmentation uses policies to restrict communication between workloads, typically at the application or service level. Deny-all by default policies between containers would prevent reconnaissance.

Answer

Enabling flow logging on the network switches.

Answer

Host-based IPS (HIPS).

Answer

Implementing a web application firewall (WAF) at the edge.

Question 4

You are the security engineer responsible for verifying the implementation of an organization's Public Key Infrastructure (PKI) as part of a system accreditation effort. The Certificate Practice Statement (CPS) states that all end-entity certificates must be issued with a maximum validity of 365 days and must include the Certificate Policies extension. During your validation, you sample issued certificates and find that a subordinate CA has been issuing certificates with a 730-day validity and no Certificate Policies extension. Which validation activity best identifies the root cause of this non-compliance?

Accepted Answer

Review the subordinate CA's certificate template and policy configuration against the CPS requirements.. The non-compliance is a deviation between the CPS and the actual certificates issued by the subordinate CA. Verifying the CA's certificate template and policy configuration directly tests whether the implementation enforces the required validity period and Certificate Policies extension. This root-cause analysis is more effective than scanning for vulnerabilities, checking revocation lists, or reviewing authentication logs, none of which examine issuance parameters.

Answer

Inspect the Certificate Revocation List (CRL) for expired or revoked end-entity certificates.

Answer

Audit the CA's audit logs for failed authentication attempts against the CA management interface.

Answer

Run a vulnerability scan against the subordinate CA server to identify missing security patches.

Question 5

You are assessing an Engineered System that uses 'Hardware Security Modules' (HSM). Which THREE of the following are the most critical administrative risks to address in an HSM policy?

Accepted Answer

Lack of audit logs for access to the HSM's administrative interface.. Option C is correct because without audit logs for the HSM administrative interface, there is no tamper-evident record of who accessed the device, when, and what commands were executed, which defeats accountability and forensic investigation requirements for cryptographic modules. Option D is correct because an insecure key ceremony—where key material, split knowledge, or M-of-N shares can be observed, copied, or handled by a single person—directly compromises the root of trust the HSM is meant to protect, so the policy must mandate witnessed, documented, and physically controlled ceremonies. Option E is correct because lack of separation of duties allows one administrator to perform sensitive operations alone (e.g., key generation, backup, and recovery), violating dual-control and split-knowledge principles required for HSM administration. Option A is not among the marked answers because it addresses only physical access authentication and is a weaker control than the administrative, procedural, and accountability risks covered by C, D, and E. Option B is also not marked because, while using a default vendor password is a serious weakness, it is a basic hardening/configuration issue rather than one of the three most critical administrative risks in an HSM policy.

Answer

Only requiring a password for physical access to the HSM appliance.

Answer

Using the default vendor password for the HSM web UI.

Question 6

Which TWO architectural patterns are considered best practices for securing cloud-native applications?

Accepted Answer

Zero-trust network architecture. Cloud security relies on zero-trust and defense-in-depth principles implemented through infrastructure-as-code and micro-segmentation.

Answer

Hardcoded credentials in application code

Answer

Public access to all S3 buckets

Answer

Monolithic application architecture

Question 7

When validating the security of a database implementation, how do you verify that sensitive data at rest is encrypted using Transparent Data Encryption (TDE)?

Accepted Answer

Query the sys.dm_database_encryption_keys dynamic management view.. Verifying the system catalog or dynamic management views is the standard way to confirm TDE status.

Answer

Check if the database folder has the 'encrypted' flag set in Windows File Properties.

Answer

Attempt to open the database file in a text editor.

Answer

Use the 'encrypt' command in the database shell.

Question 8

Which TWO of the following are considered critical components of a Secure Software Development Life Cycle (SDLC)?

Accepted Answer

Threat Modeling.. Security requirements analysis and threat modeling are fundamental proactive steps in an SDLC.

Answer

Patching the OS of the build server.

Answer

Using a dark theme for the IDE.

Answer

Final penetration testing before release.

Question 9

When engineering a cryptographically secure system, what is the primary risk associated with custom cryptographic implementations?

Accepted Answer

It lacks the rigorous peer review of standard algorithms. Custom cryptography is prone to subtle implementation errors that are difficult to detect and often break the security of the underlying algorithm.

Answer

It makes key management too difficult

Answer

It is always too slow for real-time systems

Answer

It requires special hardware

Question 10

An ISSE is defining the trustworthiness requirements for a new high-assurance system that will process classified information. The program manager asks which security engineering principles should be explicitly applied to the system architecture to ensure it can enforce its security policy under attack. (Choose two.)

Accepted Answer

Tamperproof and verifiable design of the reference monitor.. The reference monitor concept requires that the enforcement mechanism completely mediate all access requests and be tamperproof and verifiable. These two properties ensure that the security policy is enforced consistently and cannot be bypassed or disabled by an attacker. Proprietary encryption, user training, and decentralization do not provide the architectural assurance needed for a high-assurance system. The correct selections are the foundational principles of a trusted computing base.

Answer

Maximum decentralization of security enforcement across all system components.

Answer

Periodic security awareness training for all users of the system.

Answer

Use of proprietary encryption algorithms to increase attacker uncertainty.

Question 11

An ISSE is leading the initial security architecture for a new Department of Defense (DoD) command-and-control system. The program manager asks how the ISSE plans to address the risk of a single component failure cascading to a mission-critical function. Which engineering principle should the ISSE apply to reduce the likelihood that one component's failure causes a total loss of the security function?

Accepted Answer

Implement redundant security mechanisms and diverse implementations so no single point of failure exists.. The scenario calls for an architectural principle that prevents a single failure from cascading to mission loss. Redundant and diverse security mechanisms eliminate single points of failure by ensuring independent controls can cover for one another. This is a foundational tenet of systems security engineering for high-assurance systems. Documentation, training, and single certified modules do not provide the same architectural fault tolerance.

Answer

Increase the security awareness training frequency for all system administrators.

Answer

Rely on a single, highly certified cryptographic module to protect all command-and-control traffic.

Answer

Document all security controls in the system security plan and require annual reviews.

Question 12

An ISSEP is conducting a risk assessment for a system that will be hosted in a multi-tenant cloud environment. Which risk is unique to the multi-tenancy model?

Accepted Answer

Risk of cross-tenant data leakage via side-channel attacks.. The 'noisy neighbor' or cross-tenant data leakage risk is inherent to multi-tenant architectures where shared hardware/hypervisor resources could potentially be exploited to access data from another tenant.

Answer

Risk of unauthorized access by the cloud provider's employees.

Answer

Difficulty in performing system backups.

Answer

Risk of data loss due to provider bankruptcy.

Question 13

When considering 'System Availability', what is the primary advantage of a 'Load Balancer' in a security engineering context?

Accepted Answer

It provides redundancy and DoS mitigation. Load balancers distribute traffic, preventing any single instance from being overwhelmed (a form of DoS mitigation) and allowing for maintenance without downtime.

Answer

It caches all static content

Answer

It replaces the need for a firewall

Answer

It encrypts all traffic

Question 14

When implementing FIPS 140-2/-3 validated cryptography in a system, what is the most important factor to verify?

Accepted Answer

Verify the module is on the NIST CMVP validated list.. The cryptographic module must be explicitly listed on the CMVP (Cryptographic Module Validation Program) validated list, not just 'based on' an algorithm.

Answer

Ensure the vendor claims the product is FIPS compliant.

Answer

Ensure the product is open source.

Answer

Verify the algorithms are AES-256.

Question 15

You are designing a secure data enclave for highly sensitive research data. What is the most robust method to enforce physical and logical separation?

Accepted Answer

Physical air-gapping and hardware-level encryption with HSMs.. Air-gapping (physical) combined with Hardware Security Modules (logical) provides the highest level of isolation for sensitive data.

Answer

Shared storage with ACLs.

Answer

VLAN tagging and firewall rules.

Answer

Container isolation with restricted network access.