PHP 'CVE-2019-11043' FPM Remote Code Execution Vulnerability (Version Check)

# 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:php:php";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.108692");
  script_version("2022-08-09T10:11:17+0000");
  script_tag(name:"last_modification", value:"2022-08-09 10:11:17 +0000 (Tue, 09 Aug 2022)");
  script_tag(name:"creation_date", value:"2019-10-25 11:55:00 +0000 (Fri, 25 Oct 2019)");
  script_tag(name:"cvss_base", value:"7.5");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2020-08-18 15:05:00 +0000 (Tue, 18 Aug 2020)");
  script_xref(name:"CISA", value:"Known Exploited Vulnerability (KEV) catalog");
  script_xref(name:"URL", value:"https://www.cisa.gov/known-exploited-vulnerabilities-catalog");
  script_cve_id("CVE-2019-11043");
  script_name("PHP 'CVE-2019-11043' FPM Remote Code Execution Vulnerability (Version Check)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2019 Greenbone Networks GmbH");
  script_family("Web application abuses");
  script_dependencies("secpod_php_smb_login_detect.nasl", "gb_php_ssh_login_detect.nasl", "gb_php_http_detect.nasl");
  script_mandatory_keys("php/detected");

  script_xref(name:"URL", value:"https://bugs.php.net/bug.php?id=78599");
  script_xref(name:"URL", value:"https://www.php.net/ChangeLog-7.php#7.3.11");
  script_xref(name:"URL", value:"https://www.php.net/ChangeLog-7.php#7.2.24");
  script_xref(name:"URL", value:"https://www.php.net/ChangeLog-7.php#7.1.33");
  script_xref(name:"URL", value:"https://github.com/neex/phuip-fpizdam");

  script_tag(name:"summary", value:"PHP is prone to a remote code execution vulnerability in certain nginx +
  php-fpm configurations.");

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

  script_tag(name:"impact", value:"Successful exploitation would allow an unauthenticated remote attacker to
  execute arbitrary code on the target machine.");

  script_tag(name:"insight", value:"The file sapi/fpm/fpm/fpm_main.c contains pointer arithmetic that assumes
  that env_path_info has a prefix equal to the path to the php script. However, the code does not check this
  assumption is satisfied. The absence of the check can lead to an invalid pointer in the 'path_info' variable.

  Such conditions can be achieved in a pretty standard Nginx configuration. The regexp in `fastcgi_split_path_info`
  directive can be broken using the newline character (in encoded form, %0a). Broken regexp leads to empty PATH_INFO,
  which triggers the bug.");

  script_tag(name:"affected", value:"PHP versions before 7.1.33, 7.2.x before 7.2.24 and 7.3.x before 7.3.11.");

  script_tag(name:"solution", value:"Update to version 7.1.33, 7.2.24, 7.3.11 or later. As an alternative a workaround
  to update the nginx configuration to mitigate this vulnerability is described at the PHP.net bugtracker linked in the
  references.");

  script_tag(name:"qod_type", value:"remote_banner_unreliable"); # Only hosts running PHP via php-fpm AND nginx with a special config are affected
  script_tag(name:"solution_type", value:"VendorFix");

  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_is_less(version: version, test_version: "7.1.33")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "7.1.33", install_path: path);
  security_message(port: port, data: report);
  exit(0);
}

else if (version_in_range(version: version, test_version: "7.2", test_version2: "7.2.23")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "7.2.24", install_path: path);
  security_message(port: port, data: report);
  exit(0);
}

else if (version_in_range(version: version, test_version: "7.3", test_version2: "7.3.10")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "7.3.11", install_path: path);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);