CAS-004 Security Engineering Practice Test 2 — 15 Questions

Question 1

A security engineer is evaluating hardware security modules (HSMs) for key management. The HSM must support key generation, storage, and cryptographic operations without exposing private keys. Additionally, the solution must comply with FIPS 140-2 Level 3. Which THREE features are essential for this requirement? (Select THREE.)

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Physical security mechanisms (e.g., locks, tamper switches). FIPS 140-2 Level 3 requires tamper-evident coatings, physical security, and cryptographic boundary. Key ceremony is a procedural control, not a feature of the HSM itself. Secure boot is for general computing. Multi-factor authentication is a user access control, not a core HSM feature.

Answer

Key ceremony support

Answer

Secure boot of the HSM firmware

Question 2

A security architect is designing a new web application that must meet strict data confidentiality and integrity requirements. The application will run in a cloud environment and must support low-latency operations. The architect is considering cipher suites for TLS 1.3. Which combination of algorithms would best meet these requirements?

Accepted Answer

ChaCha20-Poly1305 with ECDHE key exchange and Ed25519. ChaCha20-Poly1305 is a symmetric cipher that offers excellent performance on mobile and low-power devices, while providing authenticated encryption. ECDHE provides forward secrecy, and Ed25519 provides efficient authentication. AES-256-GCM is also good but ChaCha20 often performs better in software. RSA key exchange does not provide forward secrecy. SHA-256 is a hashing algorithm, not an encryption algorithm.

Answer

AES-128-CBC with HMAC-SHA256 and RSA-2048

Answer

ChaCha20-Poly1305 with static ECDH and SHA-384

Answer

AES-256-GCM with RSA key exchange and SHA-256

Question 3

An organization is implementing a PKI to issue certificates for internal applications. The security team wants to minimize the risk of compromise to the root CA. Which of the following is the BEST practice to protect the root CA?

Accepted Answer

Keep the root CA offline and store its private key in a hardware security module. Keeping the root CA offline and using a hardware security module (HSM) for key storage ensures its private key is never exposed to network threats. This is a standard best practice.

Answer

Delegate root CA responsibilities to a public CA

Answer

Install the root CA on a VM with strict firewall rules

Answer

Use a self-signed certificate for the root CA and distribute it manually

Question 4

A company is migrating its internal services to use SSH key-based authentication instead of passwords. The security policy requires using the strongest supported algorithms. The SSH server supports the following key exchange algorithms: diffie-hellman-group14-sha256, ecdh-sha2-nistp384, curve25519-sha256. Which algorithm should the administrator choose to meet the policy?

Accepted Answer

curve25519-sha256. Curve25519 (X25519) is the recommended elliptic curve for key exchange due to its strong security and performance advantages. It is considered more secure than NIST curves and traditional Diffie-Hellman.

Answer

ecdh-sha2-nistp384

Answer

diffie-hellman-group14-sha256

Answer

All three are equally strong

Question 5

A security auditor is reviewing the cryptographic controls of a financial application that processes transactions. The application uses digital signatures with RSA 4096 and SHA-256. The auditor recommends migrating to a stronger algorithm due to concerns about long-term security and quantum resistance. Which of the following would be the MOST appropriate replacement?

Accepted Answer

Ed25519. Ed25519 offers strong security, smaller keys, and better performance than RSA. It is also resistance to some side-channel attacks. While not quantum-resistant, it is a forward-looking choice. ECDSA P-384 is also strong but larger key sizes. SHA-3 is a hash function, not a signature algorithm.

Answer

SHA-3

Answer

ECDSA P-521

Answer

ECDSA P-256

Question 6

An organization is deploying a new IoT device that must securely update its firmware over the air (OTA). The device has limited processing power and memory. Which cryptographic solution would provide the BEST balance of security and performance for verifying firmware updates?

Accepted Answer

Ed25519 digital signatures. Ed25519 is a fast and secure digital signature algorithm that performs well on constrained devices. RSA 4096 is computationally expensive. HMAC-SHA256 is a symmetric key technique and requires key management overhead. AES-256-GCM is for encryption, not verification.

Answer

RSA-4096 digital signatures

Answer

HMAC-SHA256 with pre-shared key

Answer

AES-256-GCM for authentication

Question 7

A security engineer is configuring a new web server to support TLS 1.3. The server must provide forward secrecy and support clients that may not have updated certificates frequently. Which of the following is a feature of TLS 1.3 that addresses these requirements?

Accepted Answer

Mandatory use of ephemeral Diffie-Hellman key exchange. TLS 1.3 mandates forward secrecy by requiring ephemeral Diffie-Hellman (ECDHE) key exchange for all sessions. This ensures that if the server's long-term private key is compromised, past session keys remain secure. While TLS 1.3 does remove cipher suites that use RSA key exchange (which lack forward secrecy), this removal does not directly address the requirement to support clients with infrequently updated certificates. The question asks for a feature that satisfies both forward secrecy and support for clients with infrequently updated certificates; only mandatory use of ephemeral Diffie-Hellman key exchange directly provides forward secrecy, which is the key requirement.

Answer

Support for certificate pinning

Answer

Support for 0-RTT handshake

Answer

Removal of cipher suites that use RSA key exchange

Question 8

An organization is implementing a Windows Hello for Business deployment to enable passwordless authentication. The solution uses TPM 2.0 for key storage. Which of the following TPM features ensures that the system has not been tampered with before the user authenticates?

Accepted Answer

Measured boot. Measured boot records measurements of boot components in PCR banks, which can be used for attestation to verify system integrity. Secure boot prevents execution of unauthorized code, but measured boot provides evidence of the boot chain. Sealed storage uses PCR values to restrict access to keys. Attestation is the process of proving the measurements to a verifier.

Answer

Secure boot

Answer

Sealed storage

Answer

Attestation

Question 9

A security architect is evaluating hardware security modules (HSMs) for a new PKI deployment. The HSM must be compliant with FIPS 140-2 Level 3. Which of the following is a requirement for Level 3 that distinguishes it from Level 2?

Accepted Answer

Identity-based authentication for operators. FIPS 140-2 Level 3 requires tamper-evident enclosures with active tamper response mechanisms (e.g., erasing keys) and identity-based authentication. Level 2 requires tamper-evident coatings or seals but not active response. Level 4 is more stringent.

Answer

Cryptographic boundary includes all critical components

Answer

Environmental failure protections

Answer

Physical security mechanisms that provide tamper evidence

Question 10

An enterprise is deploying a multi-factor authentication (MFA) solution. The security team requires a factor that is resistant to phishing and does not rely on shared secrets. Which of the following MFA types BEST meets this requirement?

Accepted Answer

FIDO2/WebAuthn security keys. FIDO2/WebAuthn uses public-key cryptography, with the private key stored on the device, and the protocol is designed to be phishing-resistant by binding credentials to the origin. TOTP/HOTP rely on shared secrets and are vulnerable to phishing. Hardware tokens like YubiKey can implement FIDO2. Biometrics are a factor but not inherently phishing-resistant alone.

Answer

Biometric fingerprint scanner

Answer

SMS one-time passcodes

Answer

TOTP via authenticator app

Question 11

A security administrator is configuring IPsec VPN between two sites. The data transmitted includes sensitive financial records. The administrator wants to ensure both confidentiality and integrity of the data, and also wants to authenticate the source. Which IPsec protocol and mode should be used?

Accepted Answer

ESP in tunnel mode. ESP (Encapsulating Security Payload) provides both confidentiality and integrity (optionally authentication). AH only provides integrity and authentication but not confidentiality. Transport mode encrypts only the payload, while tunnel mode encrypts the entire IP packet. For site-to-site VPN, tunnel mode is typically used.

Answer

AH in tunnel mode

Answer

ESP in transport mode

Answer

AH in transport mode

Question 12

An organization uses a PKI with a three-tier hierarchy: root CA, issuing CA, and registration authority. The root CA is kept offline. An intermediate CA certificate must be renewed. Which of the following is the correct process?

Accepted Answer

The root CA signs the new intermediate CA certificate after being brought online.. The root CA signs the intermediate CA certificate. Since the root CA is offline, it must be brought online temporarily to sign the new intermediate certificate. The RA does not sign certificates; it handles verification requests. The intermediate CA cannot self-sign its own certificate.

Answer

The intermediate CA self-signs its new certificate.

Answer

The issuing CA signs the new intermediate CA certificate.

Answer

The registration authority signs the new intermediate CA certificate.

Question 13

During a security assessment, a penetration tester discovers that a smart card used for authentication is vulnerable to a timing attack. The card uses a cryptographic algorithm that has data-dependent timing variations. Which of the following algorithms is MOST likely being used on the smart card?

Accepted Answer

RSA with Chinese Remainder Theorem. RSA decryption (using CRT) is known to be vulnerable to timing attacks if not implemented with constant-time functions. AES is typically resistant if implemented correctly. SHA-256 is a hash function, not used for signing/decryption. ECDSA can be vulnerable to timing attacks if not constant-time, but RSA is more commonly associated with classic timing vulnerabilities.

Answer

ECDSA P-384

Answer

SHA-256

Answer

AES-256-CBC

Question 14

A security architect is designing a just-in-time (JIT) privileged access management (PAM) solution. Which TWO of the following are key characteristics of JIT access?

Accepted Answer

Access rights are automatically revoked after use or expiry.. JIT access provisioning grants temporary privileges that are automatically revoked after a set time or after use. This reduces the attack surface. Standing privileges are the opposite. Approval workflows are not necessarily part of JIT; JIT can be automatic. Break-glass accounts are for emergency access, which is a separate concept.

Answer

Privileges are permanent but require approval each time.

Answer

Break-glass accounts are used for emergency access.

Answer

Users have standing privileges for routine tasks.

Question 15

A security engineer is hardening an SSH server. The policy requires disabling all legacy algorithms and using only modern, secure cryptography. Which THREE of the following configurations should the engineer apply?

Accepted Answer

Set HMAC algorithms to use only SHA-2 or stronger.. Key-based authentication only is more secure than passwords. Disabling password authentication prevents brute-force attacks. Restricting key exchange to curve25519 ensures strong forward secrecy. Enabling root login with password is insecure. Using SHA-1 for HMAC is weak.

Answer

Allow only SSH protocol version 1 for compatibility.

Answer

Enable root login with password for administrative convenience.