osTicket Backdoored - Active Check

# Copyright (C) 2004 Noam Rathaus
# 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
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# 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:osticket:osticket";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.12649");
  script_version("2022-05-05T09:07:46+0000");
  script_tag(name:"last_modification", value:"2022-05-05 09:07:46 +0000 (Thu, 05 May 2022)");
  script_tag(name:"creation_date", value:"2005-11-03 14:08:04 +0100 (Thu, 03 Nov 2005)");
  script_tag(name:"cvss_base", value:"7.8");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:C");

  script_tag(name:"qod_type", value:"remote_vul");

  script_tag(name:"solution_type", value:"Workaround");

  script_name("osTicket Backdoored - Active Check");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2004 Noam Rathaus");
  script_family("Web application abuses");
  script_dependencies("osticket_http_detect.nasl");
  script_mandatory_keys("osticket/http/detected");
  script_require_ports("Services/www", 80);

  script_tag(name:"summary", value:"There is a vulnerability in the current version of osTicket
  that allows an attacker to upload an PHP script, and then access it causing it to execute.

  This script tries to detect infected servers.");

  script_tag(name:"vuldetect", value:"Sends a crafted HTTP GET request and checks the response.");

  script_tag(name:"impact", value:"This attack is being actively exploited by attackers to take
  over servers.");

  script_tag(name:"solution", value:"1) Remove any PHP files from the /attachments/ directory.

  2) Place an index.html file there to prevent directory listing of that directory.

  3) Update osTicket to the latest version.");

  exit(0);
}

include("host_details.inc");
include("http_func.inc");
include("http_keepalive.inc");

if( ! port = get_app_port( cpe:CPE, service:"www" ) )
  exit( 0 );

if( ! dir  = get_app_location( cpe:CPE, port:port ) )
  exit( 0 );

if( dir == "/" )
  dir = "";

req = http_get(item:dir +  "/attachments/", port:port);
res = http_keepalive_send_recv(port:port, data:req);
if( isnull( res ) || "[DIR]" >!< res )
  exit( 0 );

# There is a directory there, so directory listing worked
v = eregmatch( pattern:'<A HREF="([^"]+.php)">', string:res );
if( isnull( v ) )
  exit( 0 );

url = dir + "/attachments/" + v[1];
req = http_get( item:url, port:port );
res = http_keepalive_send_recv( port:port, data:req );
if( isnull( res ) )
  exit( 0 );

if( "PHP Shell" >< res || "<input type = 'text' name = 'cmd' value = '' size = '75'>" >< res ) {
  report = http_report_vuln_url( port:port, url:url );
  security_message( port:port, data:report );
  exit( 0 );
}

exit( 99 );