Comprehensive Explanation from CEH v13 Courseware:
CEH v13 describes worms as standalone malicious programs capable of self-replication without requiring user assistance. Unlike viruses, which need a host file and are triggered typically by user actions, worms propagate autonomously by scanning networks, exploiting vulnerabilities, or copying themselves to accessible machines. Worms are known for causing rapid, widespread damage by consuming bandwidth, degrading system performance, and creating backdoors for attackers. Classic examples such as Conficker, WannaCry, and SQL Slammer reinforce the destructive potential of automated propagation. CEH stresses that worms often use network shares, open ports, or unpatched vulnerabilities to move laterally. In contrast, keyloggers harvest keystrokes, ransomware encrypts data and demands payment, and viruses require user involvement to spread. The behavior in the scenario-automatic replication across the network-is the defining characteristic of worm activity according to CEH's malware taxonomy.

A Cloud Access Security Broker (CASB) is a security policy enforcement point, either on-premises or in the cloud, that administers an organization's enterprise security policies when users attempt to access its cloud- based resources. A CASB can provide unified security management across multiple cloud platforms, as it can monitor cloud activity, enforce security policies, identify and respond to threats, and maintain visibility of all cloud resources. A CASB can also integrate with other security tools, such as data loss prevention (DLP), encryption, malware detection, and identity and access management (IAM), to enhance the security posture of the organization.
The other options are not as effective or feasible as using a CASB. Using a hardware-based firewall to secure all cloud resources may not be compatible with the dynamic and scalable nature of the cloud, as it may introduce latency, complexity, and cost. Implementing separate security management tools for each cloud platform may create inconsistency, inefficiency, and confusion, as each tool may have different features, interfaces, and configurations. Relying on the built-in security features of each cloud platform may not be sufficient or comprehensive, as each platform may have different levels of security, compliance, and functionality. References:
* What Is a Cloud Access Security Broker (CASB)? | Microsoft
* What Is a CASB? - Cloud Access Security Broker - Cisco
* What is a Cloud Access Security Broker (CASB)?

This scenario describes Linear Cryptanalysis, a technique detailed in CEH v13 Cryptography. Linear cryptanalysis involves finding linear approximations that relate plaintext bits, ciphertext bits, and key bits using XOR operations. By analyzing a large number of known plaintext-ciphertext pairs, attackers can identify statistical biases that reveal information about the secret key.
CEH v13 explains that linear cryptanalysis differs from differential cryptanalysis in its approach. While differential cryptanalysis studies how differences in plaintext affect differences in ciphertext, linear cryptanalysis focuses on linear relationships and probability distributions.
The mention of XOR combinations and statistical analysis of plaintext-ciphertext pairs directly aligns with linear cryptanalysis. Brute-force attacks attempt all keys without analysis. Differential cryptanalysis focuses on input differences, not linear equations. Side-channel attacks exploit physical characteristics such as power consumption or timing.
Modern block ciphers like AES are designed to resist linear cryptanalysis by ensuring that linear approximations occur with probabilities close to random. CEH v13 highlights linear cryptanalysis as a foundational attack method used to evaluate cipher strength.
Therefore, Option C is correct.