A cybersecurity analyst has been asked to review firewall configurations and recommend which ports to deny in order to prevent users from making outbound non-encrypted connections to the Internet. The organization is concerned that traffic through this type of port is insecure and may be used as an attack vector. Which port should the analyst recommend be denied?

The question asks to deny outbound non-encrypted connections to the Internet. Port 80 is the standard port for Hypertext Transfer Protocol (HTTP), which is an unencrypted protocol used for web traffic. Blocking this port directly prevents users from accessing websites that do not use encryption, thereby addressing the organization's concern about insecure traffic being used as an attack vector. This is a common security practice to enforce an "HTTPS-only" policy for web browsing.

A. Port 3389 is for Remote Desktop Protocol (RDP). While it can be insecure if not configured properly, it is not the primary port for general non-encrypted Internet connections by users.
B. Port 25 is for Simple Mail Transfer Protocol (SMTP). It is used for sending email and is often unencrypted, but it is not the port for general web browsing.
C. Port 443 is for Hypertext Transfer Protocol Secure (HTTPS). This is the encrypted version of HTTP, and blocking it would prevent secure web connections, which is the opposite of the stated goal.

1. Kurose, J. F., & Ross, K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson. In Chapter 2, Section 2.2, the text explicitly defines HTTP as using TCP port 80 and being a cleartext protocol, while HTTPS uses port 443 for encrypted communication.

2. Internet Assigned Numbers Authority (IANA). (n.d.). Service Name and Transport Protocol Port Number Registry. Retrieved from https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml. The official IANA registry lists port 80 for "http" (World Wide Web HTTP) and port 443 for "https" (http protocol over TLS/SSL).

3. National Institute of Standards and Technology (NIST). (2010). Guidelines on Securing Public Web Servers (NIST Special Publication 800-44 Version 2). Section 3.4.1 discusses restricting network access and mentions the standard ports for HTTP (80) and HTTPS (443).