KilerRat Trojan Detection

# Copyright (C) 2017 Greenbone Networks GmbH
#
# 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.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.140235");
  script_version("2020-08-26T13:46:49+0000");
  script_tag(name:"cvss_base", value:"10.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_tag(name:"last_modification", value:"2020-08-26 13:46:49 +0000 (Wed, 26 Aug 2020)");
  script_tag(name:"creation_date", value:"2017-04-05 15:14:52 +0200 (Wed, 05 Apr 2017)");
  script_name("KilerRat Trojan Detection");
  script_category(ACT_GATHER_INFO);
  script_family("Malware");
  script_copyright("Copyright (C) 2017 Greenbone Networks GmbH");
  script_dependencies("find_service.nasl");
  script_require_ports(6666);

  script_tag(name:"summary", value:"The remote host seems to be infected by the KilerRat remote access trojan.");

  script_tag(name:"vuldetect", value:"Check the response on port 6666.");

  script_tag(name:"solution", value:"A whole cleanup of the infected system is recommended.");

  script_xref(name:"URL", value:"https://www.alienvault.com/blogs/labs-research/kilerrat-taking-over-where-njrat-remote-access-trojan-left-off");

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

  exit(0);
}

include("misc_func.inc");
include("socket_func.inc");

port = 6666;
if( ! get_port_state( port ) )
  exit( 0 );

vt_strings = get_vt_strings();

data = '0|Kiler|' + vt_strings["default"] + '|Kiler|' + vt_strings["default"] + '|Kiler[endof]';
buf = socket_send_recv( port:port, data:data, length:64 );
if( ! buf || ! strlen( buf ) > 0 )
  exit( 0 );

# TBD: The data from above is an OR regex here causing false positives
# The check itself is also quite error prone and AFAICS would only check for a C&C and not for the trojan
if( buf =~ '^ACK' + data + '$' ) {
  security_message( port:port, data:'The KilerRat trojan seems to be running at this port.\n\nResponse:\n\n' + buf );
  exit( 0 );
}

exit( 0 );