Nmap dns-brute NSE Script


This page contains detailed information about how to use the dns-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/dns-brute.nse
Script categories: intrusive, discovery
Target service / protocol: -
Target network port(s): -
List of CVEs: -

Script Description

The dns-brute.nse script attempts to enumerate DNS hostnames by brute force guessing of common subdomains. With the dns-brute.srv argument, dns-brute will also try to enumerate common DNS SRV records.

Wildcard records are listed as "*A" and "*AAAA" for IPv4 and IPv6 respectively.

Dns-brute NSE Script Arguments

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

dns-brute.domain

Domain name to brute force if no host is specified

dns-brute.hostlist

The filename of a list of host strings to try. Defaults to "nselib/data/vhosts-default.lst"

dns-brute.srv

Perform lookup for SRV records

dns-brute.srvlist

The filename of a list of SRV records to try. Defaults to "nselib/data/dns-srv-names"

dns-brute.threads

Thread to use (default 5).

max-newtargets

Sets the number of the maximum allowed new targets. If set to 0 or less then there is no limit. The default value is 0.

newtargets

If specified, lets NSE scripts add new targets.

- - -
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=dns-brute --script-args dns-brute.domain=value,dns-brute.hostlist=value <target>

Dns-brute NSE Script Example Usage

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

nmap --script dns-brute --script-args dns-brute.domain=foo.com,dns-brute.threads=6,dns-brute.hostlist=./hostfile.txt,newtargets -sS -p 80

nmap --script dns-brute www.foo.com

Dns-brute NSE Script Example Output

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

Pre-scan script results:
| dns-brute:
|   DNS Brute-force hostnames
|     www.foo.com - 127.0.0.1
|     mail.foo.com - 127.0.0.2
|     blog.foo.com - 127.0.1.3
|     ns1.foo.com - 127.0.0.4
|     admin.foo.com - 127.0.0.5
|_    *A: 127.0.0.123

Dns-brute NSE Script Example XML Output

Here's a sample XML output from the dns-brute.nse script produced by providing the -oX <file> Nmap option:

 <table key="DNS Brute-force hostnames">
   <table>
     <elem key="address">127.0.0.1</elem>
     <elem key="hostname">www.foo.com</elem>
   </table>
   <table>
     <elem key="address">127.0.0.2</elem>
     <elem key="hostname">mail.foo.com</elem>
   </table>
   <table>
     <elem key="address">127.0.1.3</elem>
     <elem key="hostname">blog.foo.com</elem>
   </table>
   <table>
     <elem key="address">127.0.0.4</elem>
     <elem key="hostname">ns1.foo.com</elem>
   </table>
   <table>
     <elem key="address">127.0.0.5</elem>
     <elem key="hostname">admin.foo.com</elem>
   </table>
   <elem key="*A">127.0.0.123</elem>
 </table>
 <table key="SRV results"></table>

Author

  • Cirrus

References

See Also

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

Visit Nmap NSE Library for more scripts.

The dns-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.

Cannot find hostlist file, quitting

Here is a relevant code snippet related to the "Cannot find hostlist file, quitting" error message:

237:	      if not l:match("#!comment:") then
238:	        table.insert(hostlist, l)
239:	      end
240:	    end
241:	  else
242:	    stdnse.debug1("Cannot find hostlist file, quitting")
243:	    return
244:	  end
245:	
246:	  local threads, results, srvresults = {}, {}, {}
247:	  for _, dtype in ipairs({"A", "AAAA"}) do

Cannot find srvlist file, skipping

Here is a relevant code snippet related to the "Cannot find srvlist file, skipping" error message:

306:	        if ( not(done) ) then
307:	          condvar("wait")
308:	        end
309:	      end
310:	    else
311:	      stdnse.debug1("Cannot find srvlist file, skipping")
312:	    end
313:	  end
314:	
315:	  local response = stdnse.output_table()
316:	  if(#results==0) then

Version

This page has been created based on Nmap version 7.92.

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