OpenSSH <= 7.2p1 - Xauth Injection

###############################################################################
# OpenVAS Vulnerability Test
#
# OpenSSH <= 7.2p1 - Xauth Injection
#
# Authors:
# Michael Meyer <[email protected]>
#
# Copyright:
# Copyright (C) 2016 Greenbone Networks GmbH, http://www.greenbone.net
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2
# (or any later version), as published by the Free Software Foundation.
#
# 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:openbsd:openssh";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.105581");
  script_version("2020-03-06T09:16:18+0000");
  script_cve_id("CVE-2016-3115");
  script_tag(name:"cvss_base", value:"5.5");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:S/C:P/I:P/A:N");
  script_tag(name:"last_modification", value:"2020-03-06 09:16:18 +0000 (Fri, 06 Mar 2020)");
  script_tag(name:"creation_date", value:"2016-03-21 11:45:13 +0100 (Mon, 21 Mar 2016)");
  script_name("OpenSSH <= 7.2p1 - Xauth Injection");
  script_copyright("Copyright (C) 2016 Greenbone Networks GmbH");
  script_category(ACT_GATHER_INFO);
  script_family("General");
  script_dependencies("gb_openssh_consolidation.nasl");
  script_mandatory_keys("openssh/detected");

  script_xref(name:"URL", value:"http://www.openssh.com/txt/release-7.2p2");

  script_tag(name:"summary", value:"openssh xauth command injection may lead to forced-command and
  /bin/false bypass");

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

  script_tag(name:"insight", value:"An authenticated user may inject arbitrary xauth commands by sending an
  x11 channel request that includes a newline character in the x11 cookie. The newline acts as a command
  separator to the xauth binary. This attack requires the server to have 'X11Forwarding yes' enabled.
  Disabling it, mitigates this vector.");

  script_tag(name:"impact", value:"By injecting xauth commands one gains limited* read/write arbitrary files,
  information leakage or xauth-connect capabilities.");

  script_tag(name:"affected", value:"OpenSSH versions before 7.2p2.");

  script_tag(name:"solution", value:"Upgrade to OpenSSH version 7.2p2 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( vers =~ "^[0-6]\." || vers =~ "^7\.[01]($|[^0-9])" || vers =~ "^7.2($|p1)" ) {
  report = report_fixed_ver( installed_version:vers, fixed_version:"7.2p2", install_path:path );
  security_message( port:port, data:report );
  exit( 0 );
}

exit( 99 );