An IT company has just been hit with a severe external security breach. To enhance the company’s security posture, the network admin has decided to first block all the services and then individually enable only the necessary services. What is such an Internet access policy called?

A Paranoid Policy is the most restrictive type of security policy. It operates on a "default deny" or "deny all, permit by exception" principle. This means all traffic, services, and access are blocked by default, and only services that are explicitly and individually vetted and approved are enabled. This approach maximizes security by minimizing the attack surface, which directly aligns with the administrator's action of blocking all services first and then enabling only the necessary ones after a security breach.

A. Prudent Policy: This policy is less restrictive, blocking only known dangerous services and allowing all others. It is a "default allow" approach.
B. Permissive Policy: This is the least restrictive policy, allowing wide access with minimal blocking, typically only for known malicious activities.
C. Promiscuous Policy: This term typically describes a network interface mode that accepts all traffic, not a firewall access policy. It implies no restrictions.

1. Zwicky, E. D., Cooper, S., & Chapman, D. B. (2000). Building Internet Firewalls, 2nd Edition. O'Reilly & Associates. (See Chapter 4, "Firewall Design," Section 4.2.2, "Firewall Policy," which describes the "Paranoid" stance as "deny everything that is not explicitly permitted").

2. Purdue University, Information Technology. (2007). Firewall Policy Guideline. (See Section "Firewall Policy Types," which contrasts Permissive, Prudent, and Paranoid policies, defining Paranoid as the most secure "deny all" approach).