Modbus Unit ID and Station ID Enumerator - Metasploit


This page contains detailed information about how to use the auxiliary/scanner/scada/modbus_findunitid metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Table Of Contents
hide

Module Overview

Name: Modbus Unit ID and Station ID Enumerator
Module: auxiliary/scanner/scada/modbus_findunitid
Source code: modules/auxiliary/scanner/scada/modbus_findunitid.rb
Disclosure date: 2012-10-28
Last modification time: 2022-01-23 15:28:32 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: -
Target network port(s): 502
List of CVEs: -

Modbus is a cleartext protocol used in common SCADA systems, developed originally as a serial-line (RS232) async protocol, and later transformed to IP, which is called ModbusTCP. default tcp port is 502. This module sends a command (0x04, read input register) to the modbus endpoint. If this command is sent to the correct unit-id, it returns with the same function-id. if not, it should be added 0x80, so that it sys 0x84, and an exception-code follows which do not interest us. This does not always happen, but at least the first 4 bytes in the return-packet should be exact the same as what was sent. You can change port, ip and the scan-range for unit-id. There is also added a value - BENICE - to make the scanner sleep a second or more between probes. We have seen installations where scanning too many too fast works like a DoS.

Module Ranking and Traits

Module Ranking:

  • normal: The exploit is otherwise reliable, but depends on a specific version and can't (or doesn't) reliably autodetect. More information about ranking can be found here.

Basic Usage

msf > use auxiliary/scanner/scada/modbus_findunitid
msf auxiliary(modbus_findunitid) > show targets
    ... a list of targets ...
msf auxiliary(modbus_findunitid) > set TARGET target-id
msf auxiliary(modbus_findunitid) > show options
    ... show and set options ...
msf auxiliary(modbus_findunitid) > exploit

Required Options

  • RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'

Go back to menu.

Msfconsole Usage

Here is how the scanner/scada/modbus_findunitid auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/scada/modbus_findunitid

msf6 auxiliary(scanner/scada/modbus_findunitid) > show info

       Name: Modbus Unit ID and Station ID Enumerator
     Module: auxiliary/scanner/scada/modbus_findunitid
    License: Metasploit Framework License (BSD)
       Rank: Normal
  Disclosed: 2012-10-28

Provided by:
  EsMnemon <[email protected]>

Check supported:
  No

Basic options:
  Name          Current Setting  Required  Description
  ----          ---------------  --------  -----------
  BENICE        1                yes       Seconds to sleep between StationID-probes, just for beeing nice
  RHOSTS                         yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT         502              yes       The target port (TCP)
  TIMEOUT       2                yes       Timeout for the network probe, 0 means no timeout
  UNIT_ID_FROM  1                yes       ModBus Unit Identifier scan from value [1..254]
  UNIT_ID_TO    254              yes       ModBus Unit Identifier scan to value [UNIT_ID_FROM..254]

Description:
  Modbus is a cleartext protocol used in common SCADA systems, 
  developed originally as a serial-line (RS232) async protocol, and 
  later transformed to IP, which is called ModbusTCP. default tcp port 
  is 502. This module sends a command (0x04, read input register) to 
  the modbus endpoint. If this command is sent to the correct unit-id, 
  it returns with the same function-id. if not, it should be added 
  0x80, so that it sys 0x84, and an exception-code follows which do 
  not interest us. This does not always happen, but at least the first 
  4 bytes in the return-packet should be exact the same as what was 
  sent. You can change port, ip and the scan-range for unit-id. There 
  is also added a value - BENICE - to make the scanner sleep a second 
  or more between probes. We have seen installations where scanning 
  too many too fast works like a DoS.

References:
  http://www.saia-pcd.com/en/products/plc/pcd-overview/Pages/pcd1-m2.aspx
  http://en.wikipedia.org/wiki/Modbus:TCP

Module Options

This is a complete list of options available in the scanner/scada/modbus_findunitid auxiliary module:

msf6 auxiliary(scanner/scada/modbus_findunitid) > show options

Module options (auxiliary/scanner/scada/modbus_findunitid):

   Name          Current Setting  Required  Description
   ----          ---------------  --------  -----------
   BENICE        1                yes       Seconds to sleep between StationID-probes, just for beeing nice
   RHOSTS                         yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT         502              yes       The target port (TCP)
   TIMEOUT       2                yes       Timeout for the network probe, 0 means no timeout
   UNIT_ID_FROM  1                yes       ModBus Unit Identifier scan from value [1..254]
   UNIT_ID_TO    254              yes       ModBus Unit Identifier scan to value [UNIT_ID_FROM..254]

Advanced Options

Here is a complete list of advanced options supported by the scanner/scada/modbus_findunitid auxiliary module:

msf6 auxiliary(scanner/scada/modbus_findunitid) > show advanced

Module advanced options (auxiliary/scanner/scada/modbus_findunitid):

   Name            Current Setting  Required  Description
   ----            ---------------  --------  -----------
   CHOST                            no        The local client address
   CPORT                            no        The local client port
   ConnectTimeout  10               yes       Maximum number of seconds to establish a TCP connection
   FuzzChar        X                yes       Sets the character to use for generating long strings
   FuzzTracer      MSFROCKS         yes       Sets the magic string to embed into fuzzer string inputs
   Proxies                          no        A proxy chain of format type:host:port[,type:host:port][...]
   SSL             false            no        Negotiate SSL/TLS for outgoing connections
   SSLCipher                        no        String for SSL cipher - "DHE-RSA-AES256-SHA" or "ADH"
   SSLVerifyMode   PEER             no        SSL verification method (Accepted: CLIENT_ONCE, FAIL_IF_NO_PEER_CERT, NONE, PEER)
   SSLVersion      Auto             yes       Specify the version of SSL/TLS to be used (Auto, TLS and SSL23 are auto-negotiate) (Accepted: Auto, TLS, SSL23, SSL3, TLS1, TLS1.1, TLS1.2)
   VERBOSE         false            no        Enable detailed status messages
   WORKSPACE                        no        Specify the workspace for this module

Auxiliary Actions

This is a list of all auxiliary actions that the scanner/scada/modbus_findunitid module can do:

msf6 auxiliary(scanner/scada/modbus_findunitid) > show actions

Auxiliary actions:

   Name  Description
   ----  -----------

Evasion Options

Here is the full list of possible evasion options supported by the scanner/scada/modbus_findunitid auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(scanner/scada/modbus_findunitid) > show evasion

Module evasion options:

   Name                Current Setting  Required  Description
   ----                ---------------  --------  -----------
   TCP::max_send_size  0                no        Maxiumum tcp segment size.  (0 = disable)
   TCP::send_delay     0                no        Delays inserted before every send.  (0 = disable)

Go back to menu.

Error Messages

This module may fail with the following error messages:

Error Messages

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

Adjusting UNIT_ID_TO to <UNIT_ID_FROM>

Here is a relevant code snippet related to the "Adjusting UNIT_ID_TO to <UNIT_ID_FROM>" error message:

55:	      datastore['UNIT_ID_FROM']=1
56:	    end
57:	
58:	    unless (1..255).include? datastore['UNIT_ID_TO']
59:	      print_status("Unit ID must be between #{datastore['UNIT_ID_FROM']} and 255")
60:	      print_warning("Adjusting UNIT_ID_TO to #{datastore['UNIT_ID_FROM']} ")
61:	      datastore['UNIT_ID_TO'] = datastore['UNIT_ID_FROM']
62:	    end
63:	
64:	    if datastore['UNIT_ID_FROM'] > datastore['UNIT_ID_TO'] then
65:	      print_warning("UNIT_ID_TO is less than UNIT_ID_FROM, setting them equal")

UNIT_ID_TO is less than UNIT_ID_FROM, setting them equal

Here is a relevant code snippet related to the "UNIT_ID_TO is less than UNIT_ID_FROM, setting them equal" error message:

60:	      print_warning("Adjusting UNIT_ID_TO to #{datastore['UNIT_ID_FROM']} ")
61:	      datastore['UNIT_ID_TO'] = datastore['UNIT_ID_FROM']
62:	    end
63:	
64:	    if datastore['UNIT_ID_FROM'] > datastore['UNIT_ID_TO'] then
65:	      print_warning("UNIT_ID_TO is less than UNIT_ID_FROM, setting them equal")
66:	      datastore['UNIT_ID_TO'] = datastore['UNIT_ID_FROM']
67:	    end
68:	
69:	    datastore['UNIT_ID_FROM'].upto(datastore['UNIT_ID_TO']) do |counter|
70:	      sploit  = start

Received: incorrect/none data from stationID <COUNTER> (probably not in use)

Here is a relevant code snippet related to the "Received: incorrect/none data from stationID <COUNTER> (probably not in use)" error message:

80:	      end
81:	
82:	      if data[0,4]  == "\x21\x00\x00\x00"  #return of the same trans-id+proto-id
83:	        print_good("Received: correct MODBUS/TCP from stationID  #{counter}")
84:	      else
85:	        print_status("Received: incorrect/none data from stationID #{counter} (probably not in use)")
86:	      end
87:	
88:	      disconnect()
89:	    end
90:	  end

Go back to menu.

References

See Also

Check also the following modules related to this module:

Authors

  • EsMnemon <esm[at]mnemonic.no>

Version

This page has been produced using Metasploit Framework version 6.2.23-dev. For more modules, visit the Metasploit Module Library.

Go back to menu.