{"description": "To set the default policy to DROP (instead of ACCEPT) for\nthe built-in INPUT chain which processes incoming packets,\nadd or correct the following line in\n\n<tt>/etc/iptables/rules.v4</tt>:\n\n<pre>:INPUT DROP [0:0]</pre>", "rationale": "In <tt>iptables</tt> the default policy is applied only after all\nthe applicable rules in the table are examined for a match. Setting the\ndefault policy to <tt>DROP</tt> implements proper design for a firewall, i.e.\nany packets which are not explicitly permitted should not be\naccepted.", "severity": "medium", "references": {"cis-csc": ["11", "14", "3", "9"], "cobit5": ["BAI10.01", "BAI10.02", "BAI10.03", "BAI10.05", "DSS05.02", "DSS05.05", "DSS06.06"], "isa-62443-2009": ["4.3.3.5.1", "4.3.3.5.2", "4.3.3.5.3", "4.3.3.5.4", "4.3.3.5.5", "4.3.3.5.6", "4.3.3.5.7", "4.3.3.5.8", "4.3.3.6.1", "4.3.3.6.2", "4.3.3.6.3", "4.3.3.6.4", "4.3.3.6.5", "4.3.3.6.6", "4.3.3.6.7", "4.3.3.6.8", "4.3.3.6.9", "4.3.3.7.1", "4.3.3.7.2", "4.3.3.7.3", "4.3.3.7.4", "4.3.4.3.2", "4.3.4.3.3"], "isa-62443-2013": ["SR 1.1", "SR 1.10", "SR 1.11", "SR 1.12", "SR 1.13", "SR 1.2", "SR 1.3", "SR 1.4", "SR 1.5", "SR 1.6", "SR 1.7", "SR 1.8", "SR 1.9", "SR 2.1", "SR 2.2", "SR 2.3", "SR 2.4", "SR 2.5", "SR 2.6", "SR 2.7", "SR 7.6"], "iso27001-2013": ["A.12.1.2", "A.12.5.1", "A.12.6.2", "A.14.2.2", "A.14.2.3", "A.14.2.4", "A.9.1.2"], "nist": ["CA-3(5)", "CM-7(b)", "SC-7(23)", "CM-6(a)"], "nist-csf": ["PR.IP-1", "PR.PT-3"], "cis": ["4.3.2.1"]}, "control_references": {"cis": ["4.3.2.1"]}, "components": [], "identifiers": {}, "ocil_clause": "the default policy for the INPUT chain is not set to DROP", "ocil": "Inspect the file <tt>/etc/sysconfig/iptables</tt> to determine\nthe default policy for the INPUT chain. It should be set to DROP:\n<pre>$ sudo grep \":INPUT\" /etc/sysconfig/iptables</pre>", "oval_external_content": null, "fixtext": "", "checktext": "", "vuldiscussion": "", "srg_requirement": "", "warnings": [{"general": "Automated remediation for this rule is disabled.\nChanging firewall settings while connected over network can\nresult in being locked out of the system."}], "conflicts": [], "requires": [], "policy_specific_content": {}, "platform": "not package[nftables] and not package[ufw]", "platforms": ["not package[nftables] and not package[ufw]"], "sce_metadata": {"platform": ["multi_platform_sle", "multi_platform_ubuntu"], "check-import": "stdout", "environment": "any", "filename": "set_iptables_default_rule.sh", "relative_path": "ubuntu2204/checks/sce/set_iptables_default_rule.sh"}, "inherited_platforms": ["package[iptables]"], "cpe_platform_names": ["not_package_nftables_and_not_package_ufw"], "inherited_cpe_platform_names": ["package_iptables"], "bash_conditional": null, "fixes": {}, "title": "Set Default iptables Policy for Incoming Packets", "definition_location": "/aptdata/openscap/scap-security-guide/linux_os/guide/system/network/network-iptables/iptables_ruleset_modifications/set_iptables_default_rule/rule.yml", "template": null}