AB Ethernet Protocol (CSP) Detection

# SPDX-FileCopyrightText: 2018 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

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.140694");
  script_version("2023-06-22T10:34:15+0000");
  script_tag(name:"last_modification", value:"2023-06-22 10:34:15 +0000 (Thu, 22 Jun 2023)");
  script_tag(name:"creation_date", value:"2018-01-19 15:48:31 +0700 (Fri, 19 Jan 2018)");
  script_tag(name:"cvss_base", value:"0.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:N");

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

  script_name("AB Ethernet Protocol (CSP) Detection");

  script_tag(name:"summary", value:"An AB Ethernet (CSP) Service is running at this host.

AB Ethernet or CSP is used by Allen Bradley inside of its software products such as RSLinx to  communicate to the
PLCs.");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2018 Greenbone AG");
  script_family("Service detection");
  script_dependencies("find_service.nasl");
  script_require_ports("Services/unknown", 2222);

  script_xref(name:"URL", value:"http://ab.rockwellautomation.com/");

  exit(0);
}

include("host_details.inc");
include("byte_func.inc");
include("port_service_func.inc");

# based on https://github.com/digitalbond/Redpoint/blob/master/cspv4-info.nse

port = unknownservice_get_port(default: 2222);

soc = open_sock_tcp(port);
if (!soc)
  exit(0);

query = raw_string(0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                   0x04, 0x00, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);

send(socket: soc, data: query);
recv = recv(socket: soc, length: 512);
close(soc);

# Protocol response detection
if (!recv || hexstr(substr(recv, 0, 1)) != "0201")
  exit(0);

set_byte_order(BYTE_ORDER_LITTLE_ENDIAN);
# Note: The session id could be written to the KB if it's used in other VT's
session_id = getdword(blob: recv, pos: 4);

service_register(port: port, ipproto: "tcp", proto: "csp");

report = 'An A/B Ethernet (CSP) service is running at this port.\n\nThe following session ID has been given:\n\n' +
         'Session ID:      ' + session_id + '\n';

log_message(port: port, data: report);

exit(0);