Dropbear SSH < 0.47 Buffer Overflow Vulnerability

# Copyright (C) 2014 SCHUTZWERK GmbH
# 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-or-later
#
# 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:dropbear_ssh_project:dropbear_ssh";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.105117");
  script_version("2022-04-14T11:24:11+0000");
  script_tag(name:"last_modification", value:"2022-04-14 11:24:11 +0000 (Thu, 14 Apr 2022)");
  script_tag(name:"creation_date", value:"2014-11-14 12:00:00 +0100 (Fri, 14 Nov 2014)");
  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_cve_id("CVE-2005-4178");

  script_name("Dropbear SSH < 0.47 Buffer Overflow Vulnerability");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2014 SCHUTZWERK GmbH");
  script_family("General");
  script_dependencies("gb_dropbear_consolidation.nasl");
  script_mandatory_keys("dropbear_ssh/detected");

  script_tag(name:"summary", value:"Dropbear SSH is prone to a buffer overflow vulnerability.");

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

  script_tag(name:"insight", value:"Versions prior 0.47 does not enforce the proper order
  of operations due to an incorrect expression.");

  script_tag(name:"impact", value:"The flaws allows authenticated users to execute arbitrary
  code via unspecified inputs that cause insufficient memory to be allocated.");

  script_tag(name:"affected", value:"Versions prior to Dropbear SSH 0.47 are vulnerable.");
  script_tag(name:"solution", value:"Updates are available.");

  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/15923");
  script_xref(name:"URL", value:"https://matt.ucc.asn.au/dropbear/CHANGES");

  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"];

ver = eregmatch( pattern:"^([0-9]+)\.([0-9]+)", string:vers );

if( isnull( ver[2] ) ) exit( 0 );

if( int( ver[1] ) > 0 ) exit( 99 );

if( version_is_less( version:ver[2], test_version:"47" ) ) {
  report = report_fixed_ver( installed_version:vers, fixed_version:"0.47", install_path:path );
  security_message( port:port, data:report );
  exit( 0 );
}

exit( 99 );