Concrete5 <= 8.5.5 Phar Deserialization Vulnerability

# SPDX-FileCopyrightText: 2021 Greenbone AG
# 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-only

CPE = "cpe:/a:concretecms:concrete_cms";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.146410");
  script_version("2025-10-22T05:39:59+0000");
  script_tag(name:"last_modification", value:"2025-10-22 05:39:59 +0000 (Wed, 22 Oct 2025)");
  script_tag(name:"creation_date", value:"2021-08-02 03:36:58 +0000 (Mon, 02 Aug 2021)");
  script_tag(name:"cvss_base", value:"6.5");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:S/C:P/I:P/A:P");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2021-08-09 14:54:00 +0000 (Mon, 09 Aug 2021)");

  script_cve_id("CVE-2021-36766");

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

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

  script_name("Concrete5 <= 8.5.5 Phar Deserialization Vulnerability");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2021 Greenbone AG");
  script_family("Web application abuses");
  script_dependencies("gb_portlandlabs_concrete_cms_http_detect.nasl");
  script_mandatory_keys("concrete_cms/detected");

  script_tag(name:"summary", value:"Concrete5 is prone to a deserialization vulnerability.");

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

  script_tag(name:"insight", value:"Concrete5 deserializes untrusted Data. The vulnerable code is
  located within the controllers/single_page/dashboard/system/environment/logging.php
  Logging::update_logging() method. User input passed through the logFile request parameter is not
  properly sanitized before being used in a call to the file_exists() PHP function. This can be
  exploited by malicious users to inject arbitrary PHP objects into the application scope (PHP
  Object Injection via phar:// stream wrapper), allowing them to carry out a variety of attacks,
  such as executing arbitrary PHP code.");

  script_tag(name:"affected", value:"Concrete5 version 8.5.5 and prior.");

  script_tag(name:"solution", value:"Update to version 8.5.6 or later.");

  script_xref(name:"URL", value:"http://karmainsecurity.com/KIS-2021-05");

  exit(0);
}

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

if (!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_equal(version: version, test_version: "8.5.5")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "8.5.6", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);