Linux: SSH AuthenticationMethods

# Copyright (C) 2021 Greenbone Networks GmbH
# 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-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.150561");
  script_version("2022-08-31T10:10:28+0000");
  script_tag(name:"last_modification", value:"2022-08-31 10:10:28 +0000 (Wed, 31 Aug 2022)");
  script_tag(name:"creation_date", value:"2021-01-15 13:47:26 +0000 (Fri, 15 Jan 2021)");
  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("Linux: SSH AuthenticationMethods");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2021 Greenbone Networks GmbH");
  script_family("Policy");
  script_dependencies("compliance_tests.nasl", "read_sshd_config.nasl");
  script_mandatory_keys("Compliance/Launch");

  script_add_preference(name:"Value", type:"entry", value:"publickey", id:1);

  script_xref(name:"URL", value:"https://linux.die.net/man/5/sshd_config");

  script_tag(name:"summary", value:"sshd reads configuration data from /etc/ssh/sshd_config (or the
file specified with -f on the command line). The file contains keyword-argument pairs, one per line.
Lines starting with '#' and empty lines are interpreted as comments. Arguments may optionally be
enclosed in double quotes in order to represent arguments containing spaces.

AuthenticationMethods specifies the authentication methods that must be successfully completed for
a user to be granted access");

  exit(0);
}

include("ssh_func.inc");
include("policy_functions.inc");

cmd = "grep '^AuthenticationMethods' /etc/ssh/sshd_config";
title = "SSH AuthenticationMethods";
solution = "Edit /etc/ssh/sshd_config";
test_type = "SSH_Cmd";
default = script_get_preference("Value", id:1);

if(get_kb_item("Policy/linux/sshd_config/ERROR")){
  value = "Error";
  compliant = "incomplete";
  comment = "Could not read /etc/ssh/sshd_config";
}else if(!value = get_kb_item("Policy/linux/sshd_config/authenticationmethods")){
  value = "Error";
  compliant = "incomplete";
  comment = "Could not get supported AuthenticationMethods from /etc/ssh/sshd_config";
}else{
  compliant = policy_setting_exact_match(value:value, set_point:default);
}

policy_reporting(result:value, default:default, compliant:compliant, fixtext:solution,
  type:test_type, test:cmd, info:comment);
policy_set_kbs(type:test_type, cmd:cmd, default:default, solution:solution, title:title,
  value:value, compliant:compliant);

exit(0);