Configure Proper Policies for INPUT of iptables

# SPDX-FileCopyrightText: 2025 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

# ------------------------------------------------------------------
# METADATA
# ------------------------------------------------------------------

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.130483");
  script_version("2025-12-10T05:45:47+0000");
  script_tag(name:"last_modification", value:"2025-12-10 05:45:47 +0000 (Wed, 10 Dec 2025)");
  script_tag(name:"creation_date", value:"2025-09-25 12:58:43 +0000 (Thu, 25 Sep 2025)");
  script_tag(name:"cvss_base", value:"0.0");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:H/Au:S/C:N/I:N/A:N");
  script_tag(name:"qod", value:"97");

  script_name("Configure Proper Policies for INPUT of iptables");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2025 Greenbone AG");
  script_family("Policy");
  script_dependencies("compliance_tests.nasl", "compliance_os_check.nasl");

  script_mandatory_keys("Compliance/Launch", "policy/ssh/login/eulerosvirtual");

  script_add_preference(name:"Status", type:"radio", value:"Incomplete;Not Compliant;Compliant", id:1);

  script_xref(name:"Policy", value:"EulerOS Virtual: EulerOS Virtual Linux Security Configuration (v1.0.0): 3. Running and Services: 3.2 Firewall: 3.2.3 Configure Proper Policies for INPUT of iptables (Recommendation)");

  script_tag(name:"summary", value:"The INPUT chain is used to filter packets received from
external systems. For any service provided for external systems, configure the corresponding INPUT
policy and enable the related port so that external clients can access the service through the port.

If the policy is not set, all packets that attempt to access related services are discarded because
the default policy is DROP.");

  exit(0);
}

include("ssh_func.inc");
include("host_details.inc");
include("policy_reporting_module.inc");

title = "Configure Proper Policies for INPUT of iptables";

solution = "Run the following command to add the ACCEPT policy to the INPUT chain:

# iptables -A INPUT -p -s -d --dport -j ACCEPT

Example:
# iptables -A INPUT -p tcp --dport 22 -j ACCEPT

Run the following command to make the configured policy take effect permanently:

# service iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables: [ OK ]

Run the following command to configure the IPv6-based policy:

# ip6tables -A INPUT -p -s -d --dport -j ACCEPT

Example:
# ip6tables -A INPUT -p tcp --dport 22 -j ACCEPT

Run the following command to make the configured policy take effect permanently:

# service ip6tables save
ip6tables: Saving firewall rules to /etc/sysconfig/ip6tables: [ OK ]";

check_type = "Manual";

action = "Needs manual check";

expected_value = script_get_preference("Status", id:1);

actual_value = expected_value;

# ------------------------------------------------------------------
# MANUAL CHECK
# ------------------------------------------------------------------

if(expected_value == "Incomplete"){
  compliant = "incomplete";
  comment = "Marked as incomplete via Policy";
}
else if(expected_value == "Compliant"){
  compliant = "yes";
  comment = "Marked as Compliant via Policy";
}
else if(expected_value == "Not Compliant"){
  compliant = "no";
  comment = "Marked as Non-Compliant via Policy.";
}

# ------------------------------------------------------------------
# REPORT
# ------------------------------------------------------------------

target = get_kb_item("policy/ssh/login/os-release");
comment = "Target: " + target + "\n" + comment;

report_audit(action: action,
             actual_value: actual_value,
             expected_value: expected_value,
             is_compliant: compliant,
             solution: solution,
             check_type: check_type,
             title: title,
             comment: comment);

exit(0);