Samba Symlink Race Vulnerability (CVE-2021-20316)

# Copyright (C) 2022 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("1.3.6.1.4.1.25623.1.0.147401");
  script_version("2023-10-19T05:05:21+0000");
  script_tag(name:"last_modification", value:"2023-10-19 05:05:21 +0000 (Thu, 19 Oct 2023)");
  script_tag(name:"creation_date", value:"2022-01-12 02:22:26 +0000 (Wed, 12 Jan 2022)");
  script_tag(name:"cvss_base", value:"6.6");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:H/Au:S/C:C/I:C/A:N");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2022-08-26 18:05:00 +0000 (Fri, 26 Aug 2022)");

  script_cve_id("CVE-2021-20316");

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

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

  script_name("Samba Symlink Race Vulnerability (CVE-2021-20316)");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2022 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 symlinc race vulnerability which can allow
  metadata read and modify outside of the exported share.");

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

  script_tag(name:"insight", value:"A malicious client can use a symlink race to access or modify
  file or directory metadata information outside of the exported share. The user must have
  permissions to read or write the metadata on the accessed file or directory.");

  script_tag(name:"affected", value:"Samba prior to version 4.15.0.");

  script_tag(name:"solution", value:"Update to version 4.15.0 or later.");

  script_xref(name:"URL", value:"https://www.samba.org/samba/history/samba-4.15.0.html");
  script_xref(name:"URL", value:"https://www.samba.org/samba/security/CVE-2021-20316.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"];
location = infos["location"];

if (version_is_less(version: version, test_version: "4.15.0")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.15.0", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);