OpenSSH 'sftp-server' Security Bypass Vulnerability - Windows

# SPDX-FileCopyrightText: 2017 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:openbsd:openssh";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.812050");
  script_version("2024-02-15T05:05:40+0000");
  script_cve_id("CVE-2017-15906");
  script_tag(name:"cvss_base", value:"5.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:P/A:N");
  script_tag(name:"last_modification", value:"2024-02-15 05:05:40 +0000 (Thu, 15 Feb 2024)");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2022-08-18 13:49:00 +0000 (Thu, 18 Aug 2022)");
  script_tag(name:"creation_date", value:"2017-10-27 13:03:59 +0530 (Fri, 27 Oct 2017)");
  script_name("OpenSSH 'sftp-server' Security Bypass Vulnerability - Windows");
  script_copyright("Copyright (C) 2017 Greenbone AG");
  script_category(ACT_GATHER_INFO);
  script_family("General");
  script_dependencies("gb_openssh_consolidation.nasl", "os_detection.nasl");
  script_mandatory_keys("openssh/detected", "Host/runs_windows");

  script_xref(name:"URL", value:"https://www.openssh.com/txt/release-7.6");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/101552");
  script_xref(name:"URL", value:"https://github.com/openbsd/src/commit/a6981567e8e");

  script_tag(name:"summary", value:"openssh is prone to a security bypass vulnerability.");

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

  script_tag(name:"insight", value:"The flaw exists in the 'process_open' function
  in sftp-server.c script which does not properly prevent write operations in
  readonly mode.");

  script_tag(name:"impact", value:"Successfully exploiting this issue allows
  local users to bypass certain security restrictions and perform unauthorized
  actions. This may lead to further attacks.");

  script_tag(name:"affected", value:"OpenSSH versions before 7.6 on Windows");

  script_tag(name:"solution", value:"Upgrade to OpenSSH version 7.6 or later.");

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

  exit(0);
}

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

vers = infos["version"];
path = infos["location"];

if(version_is_less(version:vers, test_version:"7.6")) {
  report = report_fixed_ver(installed_version:vers, fixed_version:"7.6", install_path:path);
  security_message(port:port, data:report);
  exit(0);
}

exit(99);