Nortel Networks Passwordless Router (User Level, Telnet)

# SPDX-FileCopyrightText: 2000 Victor Kirhenshtein
# 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("1.3.6.1.4.1.25623.1.0.10529");
  script_version("2023-08-01T13:29:10+0000");
  script_tag(name:"last_modification", value:"2023-08-01 13:29:10 +0000 (Tue, 01 Aug 2023)");
  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_name("Nortel Networks Passwordless Router (User Level, Telnet)");
  script_category(ACT_ATTACK);
  script_copyright("Copyright (C) 2000 Victor Kirhenshtein");
  script_family("Default Accounts");
  script_dependencies("telnetserver_detect_type_nd_version.nasl", "gb_default_credentials_options.nasl");
  script_require_ports("Services/telnet", 23);
  script_mandatory_keys("telnet/nortel_bay_networks/device/detected");
  script_exclude_keys("default_credentials/disable_default_account_checks");

  script_tag(name:"solution", value:"Telnet to this router and set a password immediately.");

  script_tag(name:"summary", value:"The remote Nortel Networks (former Bay Networks) router has
  no password for user account.");

  script_tag(name:"impact", value:"An attacker could telnet to the router and reconfigure it to lock
  you out of it, and to prevent you to use your internet connection.");

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

  exit(0);
}

if(get_kb_item("default_credentials/disable_default_account_checks"))
  exit(0);

include("telnet_func.inc");
include("misc_func.inc");
include("port_service_func.inc");
include("dump.inc");

port = telnet_get_port( default:23 );
banner = telnet_get_banner( port:port );
if( ! banner || "Bay Networks" >!< banner )
  exit( 0 );

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

buf = telnet_negotiate( socket:soc );
if( "Bay Networks" >< buf ) {
  if( "Login:" >< buf ) {
    data = string( "User\r\n" );
    send( socket:soc, data:data );
    buf2 = recv( socket:soc, length:1024 );
    close( soc );
    if( "$" >< buf2 ) {
      security_message( port:port );
      exit( 0 );
    }
    exit( 99 );
  }
}

close( soc );
exit( 99 );