Network and Security (Foundations (D315))

Correct Answer C. Use info from the first message exchange to conduct DH-based key exchange.

Explanation

In IKE Phase 1 using Main Mode, the second pair of messages is responsible for performing a Diffie-Hellman (DH) key exchange. This process allows both IPSec endpoints to generate a shared secret key securely, even over an untrusted network. The key derived from this exchange is later used for encrypting and authenticating communication between the peers.

Why other options are wrong

A. Both IPSec endpoints authenticate using the method agreed upon earlier.

Authentication occurs in the third message exchange of Phase 1, not the second. The second exchange is specifically used for the DH key exchange, which helps establish a secure channel before authentication is completed.

B. The IPSec SPI information is exchanged in order to create the first IPSec SA instance.

Security Parameter Index (SPI) information is exchanged in Phase 2 of IKE, where IPSec Security Associations (SAs) are established for secure data transfer. The second exchange in Phase 1 is focused on the DH key exchange, not SA creation.

D. Exchange cookie information to protect against a follow-on replay attack.

The exchange of cookies to prevent replay attacks occurs in the initial messages of IKE Phase 1. The second exchange is focused on generating a shared key, not handling replay protection.

Correct Answer C. Wildcard certificate

Explanation

A wildcard certificate is used to secure multiple subdomains under a single domain name. For example, a wildcard certificate for *.example.com can be used for www.example.com, mail.example.com, and blog.example.com. This is particularly useful for organizations managing multiple services under one domain, reducing the need for multiple certificates.

Why other options are wrong

A. Root certificate

A root certificate is the foundational certificate issued by a Certificate Authority (CA). It is used to sign other certificates in a Public Key Infrastructure (PKI) and does not serve the function of securing multiple subdomains.

B. Self-signed certificate

A self-signed certificate is issued by an entity for itself rather than by a trusted CA. While it can be used for internal testing, it is not recognized as valid by most browsers and does not inherently support multiple subdomains.

D. S/MIME certificate

An S/MIME (Secure/Multipurpose Internet Mail Extensions) certificate is used to encrypt and sign emails to ensure secure communication. It is unrelated to securing subdomains.

E. Code signing certificate

A code signing certificate is used to verify the authenticity and integrity of software applications. It ensures that the software has not been tampered with, but it does not provide security for web domains or subdomains.

Correct Answer C. Host-to-host

Explanation:

In IPsec, Authentication Header (AH) transport mode is typically used in host-to-host VPNs because it preserves the original IP header and only authenticates the payload. This makes it suitable for securing direct communications between two individual hosts without modifying network routing. Unlike tunnel mode, which creates a new IP header, transport mode is better for end-to-end security where both devices perform encryption and decryption.

Why other options are wrong:

A. Gateway-to-gateway

Gateway-to-gateway VPNs typically use tunnel mode instead of transport mode because tunnel mode encapsulates and protects entire IP packets, including the header. This ensures confidentiality and integrity over untrusted networks.

B. Host-to-gateway

In a host-to-gateway setup, tunnel mode is generally preferred because it allows secure communication between an individual user and a network gateway. Transport mode is not well-suited here because it does not modify IP headers, which are often required for routing in such architectures.

D. Gateway-to-host

A gateway-to-host configuration also commonly uses tunnel mode instead of transport mode. Tunnel mode ensures secure communication between a centralized VPN gateway and an individual client, making it the preferred choice for remote access VPNs.

Correct Answer:

Social engineering

Explanation:

Social engineering is a manipulation technique where attackers exploit human trust to extract sensitive information. In this case, the attacker deceives employees by pretending to be a recruiter, luring them into sharing confidential company details. Spoofing attacks involve impersonating systems or users in a technical sense, denial-of-service attacks overwhelm systems with traffic, and brute-force attacks attempt repeated logins. Since this scenario relies on tricking employees through social interaction, it is classified as social engineering

Correct Answer:

Type 1

Explanation:

A Type 1 hypervisor, also known as a bare-metal hypervisor, runs directly on the host’s hardware without the need for an underlying operating system. This design provides better performance, stronger security, and greater efficiency compared to Type 2 hypervisors, which run on top of a host OS. Type 1 hypervisors are commonly used in enterprise environments where stability, scalability, and security are priorities. Therefore, it is the most suitable choice for the company in this scenario.

Correct Answer B. To assign permissions based on the specific functions of assets

Explanation

Defining roles in IAM allows organizations to implement role-based access control (RBAC). This ensures that users are granted permissions based on their job functions rather than assigning permissions to individual users. This approach simplifies access management, improves security, and reduces administrative overhead by ensuring that users only have the access necessary to perform their tasks.

Why other options are wrong

A. To establish a hierarchy of users within an organization.

While roles may correspond to organizational hierarchy, the primary purpose is not to define hierarchy but to assign permissions based on job responsibilities. Hierarchies are more related to organizational structure rather than access control.

C. To create unique identifiers for each user.

User identifiers, such as usernames or user IDs, are separate from roles. Defining roles does not create unique user identifiers; instead, it groups users with similar responsibilities to simplify permission management.

D. To monitor user activity across the network.

IAM roles focus on access control and authorization, not directly on monitoring user activity. User activity monitoring is typically handled by security information and event management (SIEM) systems or audit logging tools.

Correct Answer C. To specify the application or service

Explanation

Port numbers are used in networking to identify specific applications or services running on a device. When data is transmitted over a network, the port number ensures that it is directed to the correct process or service on the receiving device. For example, HTTP typically uses port 80, while HTTPS uses port 443. This system allows multiple services to run on the same device without conflicts.

Why other options are wrong

A. To identify devices on the network

Devices on a network are identified using IP addresses, not port numbers. An IP address uniquely identifies a device, whereas a port number specifies which service on that device should handle the incoming data.

B. To encrypt data during transmission

Encryption is handled by protocols such as SSL/TLS or IPSec, not by port numbers. Port numbers only help in directing traffic to the appropriate application or service but do not play a role in securing the data.

D. To establish a connection

While port numbers are part of the connection process, the actual establishment of a connection is managed by protocols such as TCP (Transmission Control Protocol). The port number ensures that data is sent to the correct service, but it does not initiate or maintain the connection itself.

Correct Answer:

Grey hat hacker

Explanation:

A grey hat hacker operates between ethical and malicious hacking. They typically find vulnerabilities without prior authorization, which is unauthorized activity, but unlike black hat hackers, they do not exploit the flaw for personal gain or to cause harm. They often disclose the issue to the organization, sometimes without seeking compensation. White hat hackers, in contrast, always have permission, while insider threats come from within an organization. This scenario matches the behavior of a grey hat hacker.

Correct Answer A. A widely used standard for digital certificates

Explanation

X.509 is a widely used standard for defining digital certificates, which are essential for securing online communications. It provides the framework for Public Key Infrastructure (PKI) and ensures secure authentication, encryption, and digital signatures. X.509 certificates contain critical information, such as the public key, certificate authority details, and expiration date, which help establish trust in secure communications.

Why other options are wrong

B. A document used to encrypt data transmissions over the internet

This is incorrect because X.509 itself does not encrypt data transmissions. Instead, it provides a framework for issuing digital certificates that enable encryption through protocols like TLS/SSL. The actual encryption of data is done using cryptographic algorithms such as AES, while X.509 certificates help authenticate and secure the connections.

C. A document used to authenticate a sender's digital signature

This is incorrect because while X.509 certificates can be used in the process of verifying digital signatures, they are not solely responsible for authentication. Digital signatures use cryptographic hashing and asymmetric encryption, and X.509 certificates serve as a trust mechanism rather than the direct means of authentication.

D. A document used to verify the integrity of a website

This is incorrect because X.509 certificates are primarily used for authentication and encryption rather than directly verifying a website’s integrity. Website integrity verification involves additional security measures such as checksum validation, integrity monitoring tools, and secure coding practices, rather than just relying on a digital certificate.