Nmap ftp-brute NSE Script


This page contains detailed information about how to use the ftp-brute NSE script. For list of all NSE scripts, visit the Nmap NSE Library.

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Overview
Error Messages

Script Overview

Script source code: https://github.com/nmap/nmap/tree/master/scripts/ftp-brute.nse
Script categories: intrusive, brute
Target service / protocol: ftp
Target network port(s): 21
List of CVEs: -

Script Description

The ftp-brute.nse script performs brute force password auditing against FTP servers.

Based on old ftp-brute.nse script by Diman Todorov, Vlatko Kosturjak and Ron Bowes.

Ftp-brute NSE Script Arguments

This is a full list of arguments supported by the ftp-brute.nse script:

ftp-brute.timeout

The amount of time to wait for a response on the socket. Lowering this value may result in a higher throughput for servers having a delayed response on incorrect login attempts. (default: 5s)

creds.global

Credentials to be returned by Credentials.getCredentials regardless of the service.

creds.[service]

Credentials to be returned by Credentials.getCredentials for [service]. E.g. creds.http=admin:password

passdb

The filename of an alternate password database. Default: nselib/data/passwords.lst

unpwdb.passlimit

The maximum number of passwords passwords will return (default unlimited).

unpwdb.timelimit

The maximum amount of time that any iterator will run before stopping. The value is in seconds by default and you can follow it with ms, s, m, or h for milliseconds, seconds, minutes, or hours. For example, unpwdb.timelimit=30m or unpwdb.timelimit=.5h for 30 minutes. The default depends on the timing template level (see the module description). Use the value 0 to disable the time limit.

unpwdb.userlimit

The maximum number of usernames usernames will return (default unlimited).

userdb

The filename of an alternate username database. Default: nselib/data/usernames.lst

brute.credfile

A file containing username and password pairs delimited by '/'

brute.delay

The number of seconds to wait between guesses (default: 0)

brute.emptypass

Guess an empty password for each user (default: false)

brute.firstonly

Stop guessing after first password is found (default: false)

brute.guesses

The number of guesses to perform against each account. (default: 0 (unlimited)). The argument can be used to prevent account lockouts.

brute.mode

Can be user, pass or creds and determines what mode to run the engine in.

  • user - the unpwdb library is used to guess passwords, every password Password is tried for each user. (The user iterator is in the outer loop)
  • pass - the unpwdb library is used to guess passwords, each password Is tried for every user. (The password iterator is in the outer loop)
  • creds - a set of credentials (username and password pairs) are Guessed against the service. This allows for lists of known or common username and password combinations to be tested. If no mode is specified and the script has not added any custom iterator the pass mode will be enabled.

brute.passonly

Iterate over passwords only for services that provide only a password for authentication. (default: false)

brute.retries

The number of times to retry if recoverable failures occur. (default: 2)

brute.start

The number of threads the engine will start with. (default: 5).

brute.threads

The number of initial worker threads, the number of active threads will be automatically adjusted.

brute.unique

Make sure that each password is only guessed once (default: true)

brute.useraspass

Guess the username as password for each user (default: true)

creds.[service]

Credentials to be returned by Credentials.getCredentials for [service]. E.g. creds.http=admin:password

- - -
To use these script arguments, add them to the Nmap command line using the --script-args arg1=value,[arg2=value,..] syntax. For example:

nmap --script=ftp-brute --script-args ftp-brute.timeout=value,creds.global=value <target>

Ftp-brute NSE Script Example Usage

Here's an example of how to use the ftp-brute.nse script:

nmap --script ftp-brute -p 21 <host>

This script uses brute library to perform password
guessing.

Ftp-brute NSE Script Example Output

Here's a sample output from the ftp-brute.nse script:

PORT   STATE SERVICE
21/tcp open  ftp
| ftp-brute:
|   Accounts
|     root:root - Valid credentials
|   Statistics
|_    Performed 510 guesses in 610 seconds, average tps: 0

Ftp-brute NSE Script Example XML Output

There is no sample XML output for this module. However, by providing the -oX <file> option, Nmap will produce a XML output and save it in the file.xml file.

Author

  • Aleksandar Nikolic

References

See Also

Related NSE scripts to the ftp-brute.nse script:

Visit Nmap NSE Library for more scripts.

The ftp-brute.nse script may fail with the following error messages. Check for the possible causes by using the code snippets highlighted below found in the script source code. This can often times help in identifying the root cause of the problem.

Couldn't connect to host:

Here is a relevant code snippet related to the "Couldn't connect to host: " error message:

56:	  connect = function( self )
57:	    self.socket = brute.new_socket()
58:	    -- discard buffer, we'll create a new one over the BruteSocket later
59:	    local realsocket, code, message, buffer = ftp.connect(self.host, self.port, {request_timeout=arg_timeout})
60:	    if not realsocket then
61:	      return false, brute.Error:new( "Couldn't connect to host: " .. (code or message) )
62:	    end
63:	    self.socket.socket = realsocket
64:	    return true
65:	  end,
66:

socket error during login:

Here is a relevant code snippet related to the "socket error during login: " error message:

68:	    local buffer = stdnse.make_buffer(self.socket, "\r?\n")
69:	    local status, code, message = ftp.auth(self.socket, buffer, user, pass)
70:	
71:	    if not status then
72:	      if not code then
73:	        return false, brute.Error:new("socket error during login: " .. message)
74:	      elseif code == 530 then
75:	        return false, brute.Error:new( "Incorrect password" )
76:	      elseif code == 421 then
77:	        local err = brute.Error:new("Too many connections")
78:	        err:setReduce(true)

Incorrect password

Here is a relevant code snippet related to the "Incorrect password" error message:

70:	
71:	    if not status then
72:	      if not code then
73:	        return false, brute.Error:new("socket error during login: " .. message)
74:	      elseif code == 530 then
75:	        return false, brute.Error:new( "Incorrect password" )
76:	      elseif code == 421 then
77:	        local err = brute.Error:new("Too many connections")
78:	        err:setReduce(true)
79:	        return false, err
80:	      else

Too many connections

Here is a relevant code snippet related to the "Too many connections" error message:

72:	      if not code then
73:	        return false, brute.Error:new("socket error during login: " .. message)
74:	      elseif code == 530 then
75:	        return false, brute.Error:new( "Incorrect password" )
76:	      elseif code == 421 then
77:	        local err = brute.Error:new("Too many connections")
78:	        err:setReduce(true)
79:	        return false, err
80:	      else
81:	        stdnse.debug1("WARNING: Unhandled response: %d %s", code, message)
82:	        local err = brute.Error:new("Unhandled response")

WARNING: Unhandled response: %d %s

Here is a relevant code snippet related to the "WARNING: Unhandled response: %d %s" error message:

76:	      elseif code == 421 then
77:	        local err = brute.Error:new("Too many connections")
78:	        err:setReduce(true)
79:	        return false, err
80:	      else
81:	        stdnse.debug1("WARNING: Unhandled response: %d %s", code, message)
82:	        local err = brute.Error:new("Unhandled response")
83:	        err:setRetry(true)
84:	        return false, err
85:	      end
86:	    end

Unhandled response

Here is a relevant code snippet related to the "Unhandled response" error message:

77:	        local err = brute.Error:new("Too many connections")
78:	        err:setReduce(true)
79:	        return false, err
80:	      else
81:	        stdnse.debug1("WARNING: Unhandled response: %d %s", code, message)
82:	        local err = brute.Error:new("Unhandled response")
83:	        err:setRetry(true)
84:	        return false, err
85:	      end
86:	    end
87:

Version

This page has been created based on Nmap version 7.92.

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