CAS-004 Security Engineering Practice Test 6 — 15 Questions

Question 1

A company is evaluating multi-factor authentication methods. Which TWO are considered phishing-resistant? (Select TWO.)

Accepted Answer

FIDO2/WebAuthn. FIDO2/WebAuthn uses origin-bound keys, and hardware tokens (e.g., YubiKey) generate one-time passwords or use challenge-response resistant to phishing.

Answer

Biometric authentication on a smartphone

Answer

TOTP via mobile app

Answer

SMS one-time codes

Question 2

A security architect is designing a new authentication system for a cloud-based application that requires strong multi-factor authentication. The solution must be resistant to phishing attacks and not rely on shared secrets. Which of the following is the BEST choice?

Accepted Answer

FIDO2/WebAuthn. FIDO2/WebAuthn is a passwordless authentication protocol that uses public key cryptography and is resistant to phishing because the private key never leaves the user's device.

Answer

HOTP with a hardware token

Answer

TOTP via a mobile authenticator app

Answer

SMS one-time passcodes

Question 3

A company is deploying a new IoT device that must perform secure boot and verify the integrity of firmware updates. The device has limited processing power. Which cryptographic algorithm combination is MOST appropriate for verifying firmware signatures efficiently?

Accepted Answer

Ed25519 with BLAKE3. Ed25519 offers high performance and small key sizes compared to RSA or ECDSA, making it ideal for resource-constrained devices.

Answer

AES-256-GCM for signing

Answer

RSA-4096 with SHA-256

Answer

ECDSA P-384 with SHA-384

Question 4

An organization is implementing a PKI hierarchy. The security team wants to ensure that if an issuing CA is compromised, the root CA remains unaffected and can revoke the issuing CA's certificate. Which of the following BEST describes the recommended architecture?

Accepted Answer

A two-tier hierarchy with an offline root CA and an online issuing CA. In a hierarchical PKI, the root CA is offline and issues certificates to intermediate CAs. The root CA can revoke the intermediate CA's certificate without being compromised itself.

Answer

A single-tier CA with the root CA online and issuing certificates directly

Answer

A three-tier hierarchy with a root CA, an intermediate CA, and an issuing CA, all online

Answer

Using self-signed certificates from the issuing CA without a root CA

Question 5

A network administrator needs to establish a secure VPN tunnel between two branch offices using IPsec. The requirement is to encrypt the entire IP packet, including the original IP header. Which IPsec mode should be used?

Accepted Answer

Tunnel mode. Tunnel mode encrypts the entire IP packet and adds a new IP header, making it suitable for VPNs between networks.

Answer

AH mode

Answer

IKEv1

Answer

Transport mode

Question 6

A security analyst is reviewing TLS 1.3 configuration for a web server. The analyst wants to ensure that the configuration provides forward secrecy and prevents the reuse of session keys. Which of the following is a characteristic of TLS 1.3 that supports these goals?

Accepted Answer

Use of ephemeral Diffie-Hellman key exchange. TLS 1.3 mandates ephemeral Diffie-Hellman key exchange (ECDHE or DHE), which provides forward secrecy by generating unique session keys for each session.

Answer

0-RTT session resumption

Answer

Support for static RSA key exchange

Answer

Removal of CBC mode cipher suites

Question 7

During a security audit, it was discovered that an HSM used for code signing is FIPS 140-2 Level 3 certified. The auditor is concerned about the key ceremony process. Which of the following is a required element of a secure key ceremony for an HSM at this level?

Accepted Answer

Keys are generated inside the HSM using a key ceremony with multiple officers. FIPS 140-2 Level 3 requires that cryptographic keys be created and stored in the HSM and never exist in plaintext outside the device. A key ceremony involves splitting keys into parts (m of n) and distributing them to multiple trusted individuals.

Answer

The HSM is configured to allow remote key backup over TLS

Answer

Keys are backed up to a USB drive stored in a safe

Answer

Keys are generated on a laptop and then imported into the HSM

Question 8

A company wants to implement certificate pinning for its mobile application to prevent man-in-the-middle attacks. Which of the following is the BEST practice when implementing certificate pinning?

Accepted Answer

Pin the public key of the server certificate. Pinning the public key rather than the entire certificate allows for certificate renewal without invalidating the pin.

Answer

Disable certificate pinning after the first successful connection

Answer

Pin the root CA certificate only

Answer

Pin the entire certificate chain

Question 9

An organization is concerned about side-channel attacks on its embedded devices. Which of the following is the MOST effective countermeasure against power analysis attacks?

Accepted Answer

Using a constant-time algorithm for cryptographic operations. Power analysis attacks exploit variations in power consumption during cryptographic operations. Constant-time algorithms ensure that execution time and power consumption are independent of secret data, making them the most effective software countermeasure against such attacks. While hardware countermeasures like power randomizers exist, among the given options, constant-time algorithms directly address the root cause of power analysis leakage.

Answer

Encrypting all data in memory

Answer

Disabling debug interfaces

Answer

Increasing the clock speed of the processor

Question 10

A security engineer is configuring SSH for a jump host used to access critical servers. The engineer wants to restrict the cryptographic algorithms to the most secure options. Which of the following should be DISABLED?

Accepted Answer

Diffie-Hellman group-exchange with SHA-1. Diffie-Hellman group-exchange with SHA-1 is weak and should be disabled in favor of stronger key exchange algorithms.

Answer

AES-256-CTR

Answer

Ed25519 for host keys

Answer

HMAC-SHA2-256

Question 11

Which of the following is a primary advantage of using ChaCha20-Poly1305 over AES-256-GCM in certain environments?

Accepted Answer

Faster performance on devices without AES-NI. ChaCha20-Poly1305 is designed to be faster in software that lacks AES hardware acceleration, making it suitable for mobile devices.

Answer

Better hardware acceleration support

Answer

Higher security margin

Answer

Smaller ciphertext size

Question 12

A company is deploying a just-in-time (JIT) privileged access management solution. Which of the following BEST describes a key security benefit of JIT access?

Accepted Answer

It reduces the risk of lateral movement by limiting the duration of elevated privileges. JIT access grants temporary privileges only when needed, reducing the attack surface and the risk of standing privileges being misused.

Answer

It eliminates the need for multi-factor authentication

Answer

It replaces the need for a break-glass account

Answer

It provides continuous monitoring of all user actions

Question 13

An organization uses a TPM 2.0 for measured boot and attestation. Which TPM feature ensures that the boot process has not been tampered with by measuring each component before it executes?

Accepted Answer

Platform Configuration Registers (PCRs). Platform Configuration Registers (PCRs) store hash measurements of boot components. Any change in the boot sequence will result in different PCR values, alerting to tampering.

Answer

Endorsement Key (EK)

Answer

Secure boot

Answer

Sealed storage

Question 14

A security architect is designing a PKI for a large enterprise that issues certificates to thousands of users and devices. The architect wants to implement a mechanism to efficiently check certificate revocation status without requiring clients to download a full CRL. Which TWO technologies should be considered?

Accepted Answer

OCSP stapling. OCSP allows real-time revocation status checking without downloading a CRL. OCSP stapling improves performance by having the server present a signed OCSP response. CRL distribution points are still used but require downloads. Certificate transparency logs are for monitoring, not revocation.

Answer

CRL distribution points

Answer

Certificate transparency logs

Answer

Delta CRL

Question 15

A company is migrating its legacy VPN to use IPsec with IKEv2. The security team wants to ensure the strongest possible security. Which THREE configuration options should be selected?

Accepted Answer

Use ECDSA P-384 for authentication. IKEv2, AES-256-GCM for encryption, and ECDSA for authentication provide strong security. AES-128 is weaker, SHA-1 is deprecated, and IKEv1 is legacy.

Answer

Use SHA-1 for integrity

Answer

Use IKEv1 instead of IKEv2