Lantronix Devices Authentication Bypass Vulnerability

# 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("1.3.6.1.4.1.25623.1.0.107328");
  script_version("2023-10-12T05:05:32+0000");
  script_tag(name:"last_modification", value:"2023-10-12 05:05:32 +0000 (Thu, 12 Oct 2023)");
  script_tag(name:"creation_date", value:"2018-07-12 13:43:57 +0200 (Thu, 12 Jul 2018)");
  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:"severity_vector", value:"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2019-10-03 00:03:00 +0000 (Thu, 03 Oct 2019)");

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

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

  script_cve_id("CVE-2018-12925");

  script_name("Lantronix Devices Authentication Bypass Vulnerability");

  script_category(ACT_ATTACK);

  script_copyright("Copyright (C) 2018 Greenbone AG");
  script_family("Gain a shell remotely");
  script_dependencies("gb_lantronix_device_version.nasl");
  script_mandatory_keys("lantronix_device/detected");

  script_tag(name:"summary", value:"Lantronix devices do not require a password for telnet access.");
  script_tag(name:"vuldetect", value:"Checks if the target device is vulnerable.");
  script_tag(name:"impact", value:"If not configured manually the device has no password authentication enabled by default.
  Attackers can gain access, gather information about the internal network and try to elevate their privileges.");
  script_tag(name:"affected", value:"Lantronixs Devices with telnet access.");
  script_tag(name:"solution", value:"Consult the documentation of your device to set a proper username/password combination
  and/or restrict remote telnet access.");

  exit(0);
}

include( "host_details.inc" );

port = get_kb_item( "lantronix_device/telnet/port" );
username = "login";

if( ! get_kb_item( "lantronix_device/telnet/" + port + "/access" ) ) {

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

  recv1 = recv( socket:soc, length:2048, timeout:10 );

  if( "prompt for assistance" >< recv1 && "Username>" >< recv1 ) {
    send( socket:soc, data:username + '\r\n' );
    recv2 = recv( socket:soc, length:2048, timeout:10 );
    close( soc );

    if( recv2 =~ "Local_.+>" ) {

      vuln = TRUE;
      set_kb_item( name:"lantronix_device/telnet/" + port + "/access", value:TRUE );
    }
  }
} else {
  vuln = TRUE;
}

if( soc )
  close( soc );

if( vuln ) {
  report = "It was possible to gain telnet access with username '" + username + "' and no password.";
  security_message( port:port, data:report );
  exit( 0 );
}

exit( 99 );