OpenSSH <= 7.2p1 - Xauth Injection

# SPDX-FileCopyrightText: 2016 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("1.3.6.1.4.1.25623.1.0.105581");
  script_version("2023-07-20T05:05:17+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:"2023-07-20 05:05:17 +0000 (Thu, 20 Jul 2023)");
  script_tag(name:"severity_vector", value:"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2018-09-11 10:29:00 +0000 (Tue, 11 Sep 2018)");
  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 AG");
  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 );