Nmap smb-enum-groups NSE Script


This page contains detailed information about how to use the smb-enum-groups 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/smb-enum-groups.nse
Script categories: discovery, intrusive
Target service / protocol: smb, netbios, tcp, udp
Target network port(s): 137, 139, 445
List of CVEs: -

Script Description

The smb-enum-groups.nse script obtains a list of groups from the remote Windows system, as well as a list of the group's users. This works similarly to enum.exe with the /G switch.

The following MSRPC functions in SAMR are used to find a list of groups and the RIDs of their users. Keep in mind that MSRPC refers to groups as "Aliases".

  • Bind: bind to the SAMR service.
  • Connect4: get a connect_handle.
  • EnumDomains: get a list of the domains.
  • LookupDomain: get the RID of the domains.
  • OpenDomain: get a handle for each domain.
  • EnumDomainAliases: get the list of groups in the domain.
  • OpenAlias: get a handle to each group.
  • GetMembersInAlias: get the RIDs of the members in the groups.
  • Close: close the alias handle.
  • Close: close the domain handle.
  • Close: close the connect handle.

Once the RIDs have been termined, the

  • Bind: bind to the LSA service.
  • OpenPolicy2: get a policy handle.
  • LookupSids2: convert SIDs to usernames.

I (Ron Bowes) originally looked into the possibility of using the SAMR function LookupRids2 to convert RIDs to usernames, but the function seemed to return a fault no matter what I tried. Since enum.exe also switches to LSA to convert RIDs to usernames, I figured they had the same issue and I do the same thing.

Smb-enum-groups NSE Script Arguments

This is a full list of arguments supported by the smb-enum-groups.nse script:

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.

randomseed

Set to a value to change the filenames/service names that are randomly generated.

smbbasic

Forces the authentication to use basic security, as opposed to "extended security". Against most modern systems, extended security should work, but there may be cases where you want to force basic. There's a chance that you'll get better results for enumerating users if you turn on basic authentication.

smbport

Override the default port choice. If smbport is open, it's used. It's assumed to be the same protocol as port 445, not port 139. Since it probably isn't possible to change Windows' ports normally, this is mostly useful if you're bouncing through a relay or something.

smbsign

Controls whether or not server signatures are checked in SMB packets. By default, on Windows, server signatures aren't enabled or required. By default, this library will always sign packets if it knows how, and will check signatures if the server says to. Possible values are:

  • force: Always check server signatures, even if server says it doesn't support them (will Probably fail, but is technically more secure).
  • negotiate: [default] Use signatures if server supports them.
  • ignore: Never check server signatures. Not recommended.
  • disable: Don't send signatures, at all, and don't check the server's. not recommended. More information on signatures can be found in smbauth.lua.

- - -
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=smb-enum-groups --script-args smbdomain=value,smbhash=value <target>

Smb-enum-groups NSE Script Example Usage

Here's an example of how to use the smb-enum-groups.nse script:

nmap --script smb-enum-users.nse -p445 <host>

sudo nmap -sU -sS --script smb-enum-users.nse -p U:137,T:139 <host>

Smb-enum-groups NSE Script Example Output

Here's a sample output from the smb-enum-groups.nse script:

Host script results:
| smb-enum-groups:
|   Builtin\Administrators (RID: 544): Administrator, Daniel
|   Builtin\Users (RID: 545): <empty>
|   Builtin\Guests (RID: 546): Guest
|   Builtin\Performance Monitor Users (RID: 558): <empty>
|   Builtin\Performance Log Users (RID: 559): Daniel
|   Builtin\Distributed COM Users (RID: 562): <empty>
|   Builtin\IIS_IUSRS (RID: 568): <empty>
|   Builtin\Event Log Readers (RID: 573): <empty>
|   azure\HomeUsers (RID: 1000): Administrator, Daniel, HomeGroupUser$
|_  azure\HelpLibraryUpdaters (RID: 1003): <empty>

Smb-enum-groups NSE Script Example XML Output

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

 <table key="Builtin">
   <table key="RID 544">
     <table key="member_sids">
       <elem>S-1-5-21-12345678-1234567890-0987654321-500</elem>
       <elem>S-1-5-21-12345678-1234567890-0987654321-1001</elem>
     </table>
     <elem key="name">Administrators</elem>
     <table key="members">
       <elem>Administrator</elem>
       <elem>Daniel</elem>
     </table>
   </table>
   <table key="RID 545">
     <table key="member_sids">
       <elem>S-1-5-4</elem>
       <elem>S-1-5-11</elem>
     </table>
     <elem key="name">Users</elem>
     <table key="members"></table>
   </table>
   <table key="RID 546">
     <table key="member_sids">
       <elem>S-1-5-21-12345678-1234567890-0987654321-501</elem>
     </table>
     <elem key="name">Guests</elem>
     <table key="members">
       <elem>Guest</elem>
     </table>
   </table>
   <table key="RID 559">
     <table key="member_sids">
       <elem>S-1-5-21-12345678-1234567890-0987654321-1001</elem>
     </table>
     <elem key="name">Performance Log Users</elem>
     <table key="members">
       <elem>Daniel</elem>
     </table>
   </table>
   <table key="RID 562">
     <table key="member_sids"></table>
     <elem key="name">Distributed COM Users</elem>
     <table key="members"></table>
   </table>
   <table key="RID 568">
     <table key="member_sids">
       <elem>S-1-5-17</elem>
     </table>
     <elem key="name">IIS_IUSRS</elem>
     <table key="members"></table>
   </table>
 </table>
 <table key="azure">
   <table key="RID 1000">
     <table key="member_sids">
       <elem>S-1-5-21-12345678-1234567890-0987654321-500</elem>
       <elem>S-1-5-21-12345678-1234567890-0987654321-1001</elem>
       <elem>S-1-5-21-12345678-1234567890-0987654321-1002</elem>
     </table>
     <elem key="name">HomeUsers</elem>
     <table key="members">
       <elem>Administrator</elem>
       <elem>Daniel</elem>
       <elem>HomeGroupUser$</elem>
     </table>
   </table>
   <table key="RID 1003">
     <table key="member_sids"></table>
     <elem key="name">HelpLibraryUpdaters</elem>
     <table key="members"></table>
   </table>
 </table>

Author

  • Ron Bowes

References

See Also

Related NSE scripts to the smb-enum-groups.nse script:

Visit Nmap NSE Library for more scripts.

The smb-enum-groups.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 enumerate groups:

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

141:	local empty = {"<empty>"}
142:	
143:	action = function(host)
144:	  local status, groups = msrpc.samr_enum_groups(host)
145:	  if(not(status)) then
146:	    return stdnse.format_output(false, "Couldn't enumerate groups: " .. groups)
147:	  end
148:	
149:	  local response = stdnse.output_table()
150:	  local response_str = {}
151:

Version

This page has been created based on Nmap version 7.92.

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