TELNET port - 23 is used to gain CLI access to the machines. Allowing inbound traffic from all external IP addresses to TELNET port is vulnerable to communication sniffing, brute force attack and DoS attacks. It is a best practice to restrict access from specific IP addresses to port 23.
Recommended Mitigation
It is recommended to replace the source IP of the rule with a specific IP address or delete the rule.
Network misconfigurations
