Information
Any ports that have been opened on non-loopback addresses need firewall rules to govern traffic.
Rationale:
Without a firewall rule configured for open ports default firewall policy will drop all packets to these ports.
NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.
Solution
For each port identified in the audit which does not have a firewall rule establish a proper rule for accepting inbound connections:
# iptables -A INPUT -p <protocol> --dport <port> -m state --state NEW -j ACCEPT
For example:
# ss -tunlp |awk 'NR!=1' |awk -F ' ' '{print $1":"$5}' |awk -F ':' '($2!="127.0.0.1"){print $1" "$NF}'| while read protocol port; do iptables -A INPUT -p $protocol --dport $port -m state --state NEW -j ACCEPT; done
# service iptables save