OpenSSH < 7.2 X11 Forwarding Security Bypass Vulnerability - Linux

# 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("1.3.6.1.4.1.25623.1.0.810769");
  script_version("2024-12-13T05:05:32+0000");
  script_cve_id("CVE-2016-1908");
  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:"last_modification", value:"2024-12-13 05:05:32 +0000 (Fri, 13 Dec 2024)");
  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:"2022-08-18 13:51:00 +0000 (Thu, 18 Aug 2022)");
  script_tag(name:"creation_date", value:"2017-04-21 16:34:59 +0530 (Fri, 21 Apr 2017)");
  script_name("OpenSSH < 7.2 X11 Forwarding Security Bypass Vulnerability - Linux");
  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_unixoide");

  script_xref(name:"URL", value:"http://openwall.com/lists/oss-security/2016/01/15/13");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/84427");
  script_xref(name:"URL", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1298741#c4");
  script_xref(name:"URL", value:"http://www.openssh.com/txt/release-7.2");
  script_xref(name:"URL", value:"https://anongit.mindrot.org/openssh.git/commit/?id=ed4ce82dbfa8a3a3c8ea6fa0db113c71e234416c");
  script_xref(name:"URL", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1298741");

  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:"An access flaw was discovered in OpenSSH, it did not correctly
  handle failures to generate authentication cookies for untrusted X11 forwarding. A malicious or
  compromised remote X application could possibly use this flaw to establish a trusted connection to
  the local X server, even if only untrusted X11 forwarding was requested.");

  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 7.2 on Linux.");

  script_tag(name:"solution", value:"Update to version 7.2 or later.");

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

  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:"7.2")) {
  report = report_fixed_ver(installed_version:vers, fixed_version:"7.2", install_path:path);
  security_message(port:port, data:report);
  exit(0);
}

exit(99);