A security auditor is reviewing the configuration of a corporate firewall. The auditor notices a rule that permits 'any' source IP address to connect to an internal web server (port 80/TCP) but restricts access to only 'trusted' destination IP addresses. This rule is directly followed by a rule that implicitly denies all other traffic. What is the most significant security concern with this specific firewall rule related to the internal web server?
- AIt exposes the web server to potential attacks from any external source.
- BIt allows any internal user to access the web server.
- CIt only allows access to port 80, not 443.
- DIt prevents the web server from initiating outbound connections.
Show answer & explanationAnswer & explanation
Correct answer: A. It exposes the web server to potential attacks from any external source.
The rule permits 'any' source IP address to connect to the internal web server on port 80 (HTTP). This means the web server is publicly accessible via HTTP, making it vulnerable to various attacks from the entire internet, regardless of the 'trusted' destination restriction which is misapplied (destination refers to the target of the connection, not the source).
Why the other options are wrong
- B. While true, the primary concern is external exposure, as 'any' source IP includes external internet hosts.
- C. Port 443 (HTTPS) is a different service; the concern is the insecurity of allowing 'any' source to port 80.
- D. The rule is for inbound connections; its direct impact isn't on outbound connections initiated by the web server.
Firewall Rule Analysis
The process of examining firewall rulesets to identify potential vulnerabilities, misconfigurations, or unintended access permissions that could compromise network security.
- Rules are processed in order.
- The first matching rule is applied.
- Implicit 'deny all' is a common last rule.
- Source, Destination, Port, Protocol are key elements.
Memory trick: A firewall rule with 'any' source is like leaving your front door wide open to the entire world, not just your trusted visitors.