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3.4.4.2.3 Ensure iptables rules exist for all open ports

Information

Any ports that have been opened on non-loopback addresses need firewall rules to govern traffic.

Without a firewall rule configured for open ports default firewall policy will drop all packets to these ports.

Note:

 - Changing firewall settings while connected over network can result in being locked out of the system.
 - The remediation command opens up the port to traffic from all sources. Consult iptables documentation and set any restrictions in compliance with site policy.

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

See Also

https://workbench.cisecurity.org/benchmarks/15964

Item Details

Category: SECURITY ASSESSMENT AND AUTHORIZATION, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|CA-9, 800-53|SC-7, 800-53|SC-7(5), CSCv7|9.2, CSCv7|9.4

Plugin: Unix

Control ID: 85e60a0e5bee9493fe7e8c312169104381e89595361937f2b1f0e73849a23b45