Samba World Writable Files Vulnerability (CVE-2019-3870)

# Copyright (C) 2019 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.

CPE = 'cpe:/a:samba:samba';

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.142392");
  script_version("2021-09-06T11:01:35+0000");
  script_tag(name:"last_modification", value:"2021-09-06 11:01:35 +0000 (Mon, 06 Sep 2021)");
  script_tag(name:"creation_date", value:"2019-05-09 14:16:29 +0000 (Thu, 09 May 2019)");
  script_tag(name:"cvss_base", value:"3.6");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:L/Au:N/C:N/I:P/A:P");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2020-12-04 18:15:00 +0000 (Fri, 04 Dec 2020)");

  script_cve_id("CVE-2019-3870");

  script_tag(name:"qod_type", value:"remote_banner_unreliable");

  script_tag(name:"solution_type", value:"VendorFix");

  script_name("Samba World Writable Files Vulnerability (CVE-2019-3870)");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2019 Greenbone Networks GmbH");
  script_family("General");
  script_dependencies("smb_nativelanman.nasl", "gb_samba_detect.nasl");
  script_mandatory_keys("samba/smb_or_ssh/detected");

  script_tag(name:"summary", value:"Samba is prone to a world writeable files vulnerability.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable version is present on the target host.");

  script_tag(name:"insight", value:"During the creation of a new Samba AD DC, files are created in a the private/
  subdirectory of our install location.  This directory is typically mode 0700, that is owner (root) only access.
  However in some upgraded installations it will have other permissions, such as 0755, because this was the
  default before Samba 4.8.

  Within this directory files are created with mode 0666, that is world-writable, including a sample krb5.conf and
  the list of DNS names and servicePrincipalName values to update.");

  script_tag(name:"affected", value:"Samba 4.9 and later.");

  script_tag(name:"solution", value:"Update to version 4.9.6, 4.10.2 or later.");

  script_xref(name:"URL", value:"https://www.samba.org/samba/security/CVE-2019-3870.html");

  exit(0);
}

include("host_details.inc");
include("version_func.inc");

if (isnull(port = get_app_port(cpe: CPE)))
  exit(0);

if (!infos = get_app_version_and_location(cpe: CPE, port: port, exit_no_version: TRUE))
  exit(0);

version = infos['version'];
path = infos['location'];

if (version_in_range(version: version, test_version: "4.9.0", test_version2: "4.9.5")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.9.6", install_path: path);
  security_message(port: port, data: report);
  exit(0);
}

if (version_in_range(version: version, test_version: "4.10.0", test_version2: "4.10.1")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.10.2", install_path: path);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);