local smb = require "smb"
local stdnse = require "stdnse"
local string = require "string"
local table = require "table"

description = [[
Attempts to list shares using the <code>srvsvc.NetShareEnumAll</code> MSRPC function and
retrieve more information about them using <code>srvsvc.NetShareGetInfo</code>. If access
to those functions is denied, a list of common share names are checked.

Finding open shares is useful to a penetration tester because there may be private files
shared, or, if it's writable, it could be a good place to drop a Trojan or to infect a file
that's already there. Knowing where the share is could make those kinds of tests more useful,
except that determining where the share is requires administrative privileges already.

Running <code>NetShareEnumAll</code> will work anonymously against Windows 2000, and
requires a user-level account on any other Windows version. Calling <code>NetShareGetInfo</code>
requires an administrator account on all versions of Windows up to 2003, as well as Windows Vista
and Windows 7, if UAC is turned down.

Even if <code>NetShareEnumAll</code> is restricted, attempting to connect to a share will always
reveal its existence. So, if <code>NetShareEnumAll</code> fails, a pre-generated list of shares,
based on a large test network, are used. If any of those succeed, they are recorded.

After a list of shares is found, the script attempts to connect to each of them anonymously,
which divides them into "anonymous", for shares that the NULL user can connect to, or "restricted",
for shares that require a user account.
]]

---
--@usage
-- nmap --script smb-enum-shares.nse -p445 <host>
-- sudo nmap -sU -sS --script smb-enum-shares.nse -p U:137,T:139 <host>
--
--@output
-- Host script results:
-- |  smb-enum-shares:
-- |  |  ADMIN$
-- |  |  |  Type: STYPE_DISKTREE_HIDDEN
-- |  |  |  Comment: Remote Admin
-- |  |  |  Users: 0, Max: <unlimited>
-- |  |  |  Path: C:\WINNT
-- |  |  |  Anonymous access: <none>
-- |  |  |_ Current user ('administrator') access: READ/WRITE
-- |  |  C$
-- |  |  |  Type: STYPE_DISKTREE_HIDDEN
-- |  |  |  Comment: Default share
-- |  |  |  Users: 0, Max: <unlimited>
-- |  |  |  Path: C:\
-- |  |  |  Anonymous access: <none>
-- |  |  |_ Current user ('administrator') access: READ
-- |  |  IPC$
-- |  |  |  Type: STYPE_IPC_HIDDEN
-- |  |  |  Comment: Remote IPC
-- |  |  |  Users: 1, Max: <unlimited>
-- |  |  |  Path:
-- |  |  |  Anonymous access: READ <not a file share>
-- |_ |_ |_ Current user ('administrator') access: READ <not a file share>
-----------------------------------------------------------------------

author = "Ron Bowes"
copyright = "Ron Bowes"
license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
categories = {"discovery","intrusive"}
dependencies = {"smb-brute"}


hostrule = function(host)
  return smb.get_port(host) ~= nil
end

action = function(host)
  local status, shares, extra
  local response = {}

  -- Get the list of shares
  status, shares, extra = smb.share_get_list(host)
  if(status == false) then
    return stdnse.format_output(false, string.format("Couldn't enumerate shares: %s", shares))
  end

  -- Find out who the current user is
  local result, username, domain = smb.get_account(host)
  if(result == false) then
    username = "<unknown>"
    domain = ""
  end

  if(extra ~= nil and extra ~= '') then
    table.insert(response, extra)
  end

  for i = 1, #shares, 1 do
    local share = shares[i]
    local share_output = {}
    share_output['name'] = share['name']

    if(type(share['details']) ~= 'table') then
      share_output['warning'] = string.format("Couldn't get details for share: %s", share['details'])
    else
      local details = share['details']

      table.insert(share_output, string.format("Type: %s",           details['sharetype']))
      table.insert(share_output, string.format("Comment: %s",        details['comment']))
      table.insert(share_output, string.format("Users: %s, Max: %s", details['current_users'], details['max_users']))
      table.insert(share_output, string.format("Path: %s",           details['path']))
    end


    -- A share of 'NT_STATUS_OBJECT_NAME_NOT_FOUND' indicates this isn't a fileshare
    if(share['user_can_write'] == "NT_STATUS_OBJECT_NAME_NOT_FOUND") then
      -- Print details for a non-file share
      if(share['anonymous_can_read']) then
        table.insert(share_output, "Anonymous access: READ <not a file share>")
      else
        table.insert(share_output, "Anonymous access: <none> <not a file share>")
      end

      -- Don't bother printing this if we're already anonymous
      if(username ~= '') then
        if(share['user_can_read']) then
          table.insert(share_output, "Current user ('" .. username .. "') access: READ <not a file share>")
        else
          table.insert(share_output, "Current user ('" .. username .. "') access: <none> <not a file share>")
        end
      end
    else
      -- Print details for a file share
      if(share['anonymous_can_read'] and share['anonymous_can_write']) then
        table.insert(share_output, "Anonymous access: READ/WRITE")
      elseif(share['anonymous_can_read'] and not(share['anonymous_can_write'])) then
        table.insert(share_output, "Anonymous access: READ")
      elseif(not(share['anonymous_can_read']) and share['anonymous_can_write']) then
        table.insert(share_output, "Anonymous access: WRITE")
      else
        table.insert(share_output, "Anonymous access: <none>")
      end

      if(username ~= '') then
        if(share['user_can_read'] and share['user_can_write']) then
          table.insert(share_output, "Current user ('" .. username .. "') access: READ/WRITE")
        elseif(share['user_can_read'] and not(share['user_can_write'])) then
          table.insert(share_output, "Current user ('" .. username .. "') access: READ")
        elseif(not(share['user_can_read']) and share['user_can_write']) then
          table.insert(share_output, "Current user ('" .. username .. "') access: WRITE")
        else
          table.insert(share_output, "Current user ('" .. username .. "') access: <none>")
        end
      end
    end

    table.insert(response, share_output)
  end

  return stdnse.format_output(true, response)
end