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
Notes:
Changing firewall settings while connected over network can result in being locked out of the system.
Remediation will only affect the active system firewall, be sure to configure the default policy in your firewall management to apply on boot as well.
The remediation command opens up the port to traffic from all sources. Consult iptables documentation and set any restrictions in compliance with site policy.
This Benchmark recommendation maps to:
Red Hat Enterprise Linux 7 Security Technical Implementation Guide:
Version 2, Release: 3 Benchmark Date: 26 Apr 2019
Vul ID: V-72219
Rule ID: SV-86843r2_rule
STIG ID: RHEL-07-040100
Severity: CAT II