o [NSE] Added authentication support to MongoDB library and modified existing

scripts to support it. Added the script mongodb-brute to perform password
  brute force guessing. [Patrik]

scripts/mongodb-brute.nse

@@ -0,0 +1,101 @@
+description = [[
+Performs brute force password guessing against the MongoDB database.
+]]
+
+---
+-- @usage
+-- nmap -p 27017 <ip> --script mongodb-brute
+--
+-- @output
+-- PORT      STATE SERVICE
+-- 27017/tcp open  mongodb
+-- | mongodb-brute: 
+-- |   Accounts
+-- |     root:Password1 - Valid credentials
+-- |   Statistics
+-- |_    Performed 3542 guesses in 9 seconds, average tps: 393
+--
+
+require 'brute'
+require 'mongodb'
+require 'shortport'
+
+author = "Patrik Karlsson"
+license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
+categories = {"intrusive", "brute"}
+
+local arg_db = stdnse.get_script_args(SCRIPT_NAME .. ".db") or "admin"
+
+portrule = shortport.port_or_service({27017}, {"mongodb"})
+
+Driver = {
+	
+	new = function(self, host, port, options)
+		local o = { host = host, port = port, sock = nmap.new_socket() }
+		setmetatable(o, self)
+		self.__index = self
+		return o
+	end,
+	
+	connect = function(self)
+		return self.sock:connect(self.host, self.port)
+	end,
+	
+	login = function(self, username, password)
+		local status, resp = mongodb.login(self.sock, arg_db, username, password)
+		if ( status ) then
+			return true, brute.Account:new(username, password, creds.State.VALID)
+		elseif ( resp ~= "Authentication failed" ) then
+			local err = brute.Error:new( err )
+			err:setRetry( true )
+			return false, err					
+		end
+		return false, brute.Error:new( "Incorrect password" )
+	end,
+	
+	disconnect = function(self)
+		return self.sock:close()
+	end,
+	
+}
+
+local function needsAuth(host, port)
+	local socket = nmap.new_socket()
+	local status, result = socket:connect(host, port)
+	if ( not(status) ) then
+		return false, "Failed to connect to server"
+	end
+
+	local packet
+	status, packet = mongodb.listDbQuery()
+	if ( not(status) ) then
+		return false, result
+	end
+	
+	--- Send packet
+	status, result = mongodb.query(socket, packet)
+	if ( not(status) ) then
+		return false, result
+	end
+	
+	socket:close()
+	if ( status and result.errmsg ) then
+		return true
+	end
+	return false
+end
+
+action = function(host, port)
+
+	if ( not(needsAuth(host, port)) ) then
+		return "No authentication needed"
+	end
+
+	local engine = brute.Engine:new(Driver, host, port )
+	
+	engine.options.script_name = SCRIPT_NAME
+	engine.options.firstonly = true
+	status, result = engine:start()
+
+	return result
+end