Nmap http-form-fuzzer NSE Script


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

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Script Overview

Script source code: https://github.com/nmap/nmap/tree/master/scripts/http-form-fuzzer.nse
Script categories: fuzzer, intrusive
Target service / protocol: http, https
Target network port(s): 80, 443, 631, 7080, 8080, 8443, 8088, 5800, 3872, 8180, 8000
List of CVEs: -

Script Description

The http-form-fuzzer.nse script performs a simple form fuzzing against forms found on websites. Tries strings and numbers of increasing length and attempts to determine if the fuzzing was successful.

Http-form-fuzzer NSE Script Arguments

This is a full list of arguments supported by the http-form-fuzzer.nse script:

http-form-fuzzer.maxlength

The maximum length of a string that will be used for fuzzing, defaults to 310000

http-form-fuzzer.minlength

The minimum length of a string that will be used for fuzzing, defaults to 300000

http-form-fuzzer.targets

A table with the targets of fuzzing, for example {{path = /index.html, minlength = 40002}, {path = /foo.html, maxlength = 10000}}. The path parameter is required, if minlength or maxlength is not specified, then the values of http-form-fuzzer.minlength or http-form-fuzzer.maxlength will be used. Defaults to {{path="/"}}

smbdomain

The domain to log in with. If you aren't in a domain environment, then anything will (should?) be accepted by the server.

smbhash

A password hash to use when logging in. This is given as a single hex string (32 characters) or a pair of hex strings (both 32 characters, optionally separated by a single character). These hashes are the LanMan or NTLM hash of the user's password, and are stored on disk or in memory. They can be retrieved from memory using the fgdump or pwdump tools.

smbnoguest

Use to disable usage of the 'guest' account.

smbpassword

The password to connect with. Be cautious with this, since some servers will lock accounts if the incorrect password is given. Although it's rare that the Administrator account can be locked out, in the off chance that it can, you could get yourself in trouble. To use a blank password, leave this parameter off altogether.

smbtype

The type of SMB authentication to use. These are the possible options:

  • v1: Sends LMv1 and NTLMv1.
  • LMv1: Sends LMv1 only.
  • NTLMv1: Sends NTLMv1 only (default).
  • v2: Sends LMv2 and NTLMv2.
  • LMv2: Sends LMv2 only.
  • NTLMv2: Doesn't exist; the protocol doesn't support NTLMv2 alone. The default, NTLMv1, is a pretty decent compromise between security and compatibility. If you are paranoid, you might want to use v2 or lmv2 for this. (Actually, if you're paranoid, you should be avoiding this protocol altogether!). If you're using an extremely old system, you might need to set this to v1 or lm, which are less secure but more compatible. For information, see smbauth.lua.

smbusername

The SMB username to log in with. The forms "DOMAIN\username" and "username@DOMAIN" are not understood. To set a domain, use the smbdomain argument.

slaxml.debug

Debug level at which default callbacks will print detailed parsing info. Default: 3

http.host

The value to use in the Host header of all requests unless otherwise set. By default, the Host header uses the output of stdnse.get_hostname().

http.max-body-size

Limit the received body to specific number of bytes. An oversized body results in an error unless script argument http.truncated-ok or request option truncated_ok is set to true. The default is 2097152 (2MB). Use value -1 to disable the limit altogether. This argument can be overridden case-by-case with request option max_body_size.

http.max-cache-size

The maximum memory size (in bytes) of the cache.

http.max-pipeline

If set, it represents the number of outstanding HTTP requests that should be sent together in a single burst. Defaults to http.pipeline (if set), or to what function get_pipeline_limit returns.

http.pipeline

If set, it represents the number of HTTP requests that'll be sent on one connection. This can be set low to make debugging easier, or it can be set high to test how a server reacts (its chosen max is ignored).

http.truncated-ok

Do not treat oversized body as error. (Use response object flag truncated to check if the returned body has been truncated.) This argument can be overridden case-by-case with request option truncated_ok.

http.useragent

The value of the User-Agent header field sent with requests. By default it is "Mozilla/5.0 (compatible; Nmap Scripting Engine; https://nmap.org/book/nse.html)". A value of the empty string disables sending the User-Agent header field.

- - -
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=http-form-fuzzer --script-args http-form-fuzzer.maxlength=value,http-form-fuzzer.minlength=value <target>

Http-form-fuzzer NSE Script Example Usage

Here's an example of how to use the http-form-fuzzer.nse script:

nmap --script http-form-fuzzer --script-args 'http-form-fuzzer.targets={1={path=/},2={path=/register.html}}' -p 80 <host>

This script attempts to fuzz fields in forms it detects (it fuzzes one field at a time).
In each iteration it first tries to fuzz a field with a string, then with a number.
In the output, actions and paths for which errors were observed are listed, along with
names of fields that were being fuzzed during error occurrence. Length and type
(string/integer) of the input that caused the error are also provided.
We consider an error to be either: a response with status 500 or with an empty body,
a response that contains "server error" or "sql error" strings. ATM anything other than
that is considered not to be an 'error'.
TODO: develop more sophisticated techniques that will let us determine if the fuzzing was
successful (i.e. we got an 'error'). Ideally, an algorithm that will tell us a percentage
difference between responses should be implemented.

Http-form-fuzzer NSE Script Example Output

Here's a sample output from the http-form-fuzzer.nse script:

PORT   STATE SERVICE REASON
80/tcp open  http    syn-ack
| http-form-fuzzer:
|   Path: /register.html Action: /validate.php
|     age
|       integer lengths that caused errors:
|         10000, 10001
|     name
|       string lengths that caused errors:
|         40000
|   Path: /form.html Action: /check_form.php
|     fieldfoo
|       integer lengths that caused errors:
|_        1, 2

Http-form-fuzzer 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.

Authors

  • Piotr Olma
  • Gioacchino Mazzurco

References

See Also

Related NSE scripts to the http-form-fuzzer.nse script:

Visit Nmap NSE Library for more scripts.

The http-form-fuzzer.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.

string lengths that caused errors:

Here is a relevant code snippet related to the "string lengths that caused errors:" error message:

158:	      local affected_string, affected_int = fuzz_field(field, minlen, maxlen, postdata, sending_function)
159:	      if #affected_string > 0 or #affected_int > 0 then
160:	        local affected_next_index = #affected_fields+1
161:	        affected_fields[affected_next_index] = {name = field["name"]}
162:	        if #affected_string>0 then
163:	          table.insert(affected_fields[affected_next_index], {name="string lengths that caused errors:", table.concat(affected_string, ", ")})
164:	        end
165:	        if #affected_int>0 then
166:	          table.insert(affected_fields[affected_next_index], {name="integer lengths that caused errors:", table.concat(affected_int, ", ")})
167:	        end
168:	      end

integer lengths that caused errors:

Here is a relevant code snippet related to the "integer lengths that caused errors:" error message:

161:	        affected_fields[affected_next_index] = {name = field["name"]}
162:	        if #affected_string>0 then
163:	          table.insert(affected_fields[affected_next_index], {name="string lengths that caused errors:", table.concat(affected_string, ", ")})
164:	        end
165:	        if #affected_int>0 then
166:	          table.insert(affected_fields[affected_next_index], {name="integer lengths that caused errors:", table.concat(affected_int, ", ")})
167:	        end
168:	      end
169:	    end
170:	  end
171:	  return affected_fields

Version

This page has been created based on Nmap version 7.92.

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