Samba 4.x Multiple DoS Vulnerabilities (Mar 2021)

# 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.

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

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.117278");
  script_version("2021-08-25T12:01:03+0000");
  script_tag(name:"last_modification", value:"2021-08-25 12:01:03 +0000 (Wed, 25 Aug 2021)");
  script_tag(name:"creation_date", value:"2021-03-26 13:38:54 +0000 (Fri, 26 Mar 2021)");
  script_tag(name:"cvss_base", value:"5.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2021-05-26 19:46:00 +0000 (Wed, 26 May 2021)");

  script_cve_id("CVE-2020-27840", "CVE-2021-20277");

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

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

  script_name("Samba 4.x Multiple DoS Vulnerabilities (Mar 2021)");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2021 Greenbone Networks GmbH");
  script_family("Denial of Service");
  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 multiple Denial of Service (DoS)
  vulnerabilities.");

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

  script_tag(name:"insight", value:"The following flaws exist:

  - CVE-2020-27840: Heap corruption via crafted DN strings. An anonymous attacker can
  crash the Samba AD DC LDAP server by sending easily crafted DNs as part of a bind
  request. More serious heap corruption is likely also possible.

  - CVE-2021-20277: Out of bounds read in AD DC LDAP server. User-controlled LDAP filter
  strings against the AD DC LDAP server may crash the LDAP server.");

  script_tag(name:"affected", value:"Samba version 4.0 and later.");

  script_tag(name:"solution", value:"Update to version 4.12.12, 4.13.5, 4.14.0 or later.");

  script_xref(name:"URL", value:"https://www.samba.org/samba/security/CVE-2020-27840.html");
  script_xref(name:"URL", value:"https://www.samba.org/samba/security/CVE-2021-20277.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_in_range(version: version, test_version: "4.0", test_version2: "4.12.11")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.12.12", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

else if (version_in_range(version: version, test_version: "4.13.0", test_version2: "4.13.4")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.13.5", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);