CompTIA Tech+ (FC0-U71)SecurityMedium
A network administrator is configuring a new firewall to restrict outbound internet access for employees. The administrator wants to ensure that if a specific rule is not explicitly defined to allow traffic, that traffic is automatically blocked. Which security principle is the administrator implementing?
- ADefense in Depth
- BSeparation of Duties
- CImplicit Deny
- DLeast Privilege
Show answer & explanationAnswer & explanation
Correct answer: C. Implicit Deny
Implicit deny is a firewall rule that states that unless traffic is explicitly allowed by a rule, it is automatically denied. This ensures that only necessary and approved network communications are permitted, enhancing security.
Why the other options are wrong
- A. Defense in depth involves multiple layers of security, which is a broader concept than a single firewall rule.
- B. Separation of duties divides tasks among different individuals to prevent fraud or error, not directly related to firewall traffic rules.
- D. Least privilege applies to user permissions, granting only the minimum necessary to perform their job, not specifically firewall traffic rules.
Implicit Deny
A security principle, especially in firewalls, where any access or traffic not explicitly allowed by a rule is automatically blocked.
- Default action is to deny everything.
- Requires explicit rules for permitted traffic.
- Enhances security by limiting potential attack surfaces.
Memory trick: Deny all, unless explicitly allowed.