While perimeter defenses like firewalls and IPS provide a layer of protection, internal systems (such as network elements) must also be hardened. This includes:
Enforcing strong authentication
Applying regular patches and updates
Conducting vulnerability assessments and security audits
Security should be layered (defense in depth), and reliance on perimeter defense alone is insufficient.
Reference - CEH v13 Official Study Guide:
Module 3: Scanning Networks / Module 18: Incident Response
Quote:
"Internal systems must be hardened with secure configurations and tested regularly. A layered security approach is required even in protected environments." Incorrect Options:
B & C. Relying only on perimeter or physical security is not sufficient D). While backup sites are part of DR, they don't replace proactive protection

A rootkit is primarily designed to replace or modify legitimate system programs and processes to hide malicious activity and maintain privileged access while avoiding detection.

The CEH IDS/IPS Evasion module describes packet fragmentation as a common evasion technique used to bypass signature-based detection.
Option B is correct.
Other options represent different attack categories.
CEH highlights reassembly normalization as a countermeasure.

A deauthentication attack forces clients to reconnect to the wireless network, allowing the attacker to capture the WPA/WPA2 authentication handshake during the reconnection process.

Comprehensive and Detailed Explanation:
Containers share the same host operating system kernel, unlike VMs which run isolated kernels. This shared kernel increases the attack surface - a compromise in one container can potentially affect the entire host if kernel-level access is obtained.
From CEH v13 Courseware:
Module 14: Hacking Web Applications # Container Security
"Containers are less secure because they share the host kernel. Attackers compromising the container can exploit vulnerabilities in the shared OS." Reference: OWASP Container Security Guide