A large mobile telephony and data network operator has a data center that houses network...

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

===========