local brute = require "brute" local coroutine = require "coroutine" local creds = require "creds" local shortport = require "shortport" local smtp = require "smtp" local stdnse = require "stdnse" description = [[ Performs brute force password auditing against SMTP servers using either LOGIN, PLAIN, CRAM-MD5, DIGEST-MD5 or NTLM authentication. ]] --- -- @usage -- nmap -p 25 --script smtp-brute -- -- @output -- PORT STATE SERVICE REASON -- 25/tcp open stmp syn-ack -- | smtp-brute: -- | Accounts -- | braddock:jules - Valid credentials -- | lane:sniper - Valid credentials -- | parker:scorpio - Valid credentials -- | Statistics -- |_ Performed 1160 guesses in 41 seconds, average tps: 33 -- -- @args smtp-brute.auth authentication mechanism to use LOGIN, PLAIN, -- CRAM-MD5, DIGEST-MD5 or NTLM -- Version 0.1 -- Created 07/15/2011 - v0.1 - created by Patrik Karlsson author = "Patrik Karlsson" license = "Same as Nmap--See https://nmap.org/book/man-legal.html" categories = {"brute", "intrusive"} portrule = shortport.port_or_service({ 25, 465, 587 }, { "smtp", "smtps", "submission" }) local mech -- By using this connectionpool we don't need to reconnect the socket -- for each attempt. ConnectionPool = {} Driver = { -- Creates a new driver instance -- @param host table as received by the action method -- @param port table as received by the action method -- @param pool an instance of the ConnectionPool new = function(self, host, port) local o = { host = host, port = port } setmetatable(o, self) self.__index = self return o end, -- Connects to the server (retrieves a connection from the pool) connect = function( self ) self.socket = ConnectionPool[coroutine.running()] if ( not(self.socket) ) then self.socket = smtp.connect(self.host, self.port, { ssl = true, recv_before = true }) if ( not(self.socket) ) then return false end ConnectionPool[coroutine.running()] = self.socket end return true end, -- Attempts to login to the server -- @param username string containing the username -- @param password string containing the password -- @return status true on success, false on failure -- @return brute.Error on failure and creds.Account on success login = function( self, username, password ) local status, err = smtp.login( self.socket, username, password, mech ) if ( status ) then smtp.quit(self.socket) ConnectionPool[coroutine.running()] = nil return true, creds.Account:new(username, password, creds.State.VALID) end if ( err:match("^ERROR: Failed to .*") ) then self.socket:close() ConnectionPool[coroutine.running()] = nil local err = brute.Error:new( err ) -- This might be temporary, set the retry flag err:setRetry( true ) return false, err end return false, brute.Error:new( "Incorrect password" ) end, -- Disconnects from the server (release the connection object back to -- the pool) disconnect = function( self ) return true end, } local function fail (err) return stdnse.format_output(false, err) end action = function(host, port) local socket, response = smtp.connect(host, port, { ssl = true, recv_before = true }) if ( not(socket) ) then return fail("Failed to connect to SMTP server") end local status, response = smtp.ehlo(socket, smtp.get_domain(host)) if ( not(status) ) then return fail("EHLO command failed, aborting ...") end local mechs = smtp.get_auth_mech(response) if ( not(mechs) ) then return fail("Failed to retrieve authentication mechanisms form server") end smtp.quit(socket) local mech_prio = stdnse.get_script_args("smtp-brute.auth") mech_prio = ( mech_prio and { mech_prio } ) or { "LOGIN", "PLAIN", "CRAM-MD5", "DIGEST-MD5", "NTLM" } for _, mp in ipairs(mech_prio) do for _, m in pairs(mechs) do if ( mp == m ) then mech = m break end end if ( mech ) then break end end local engine = brute.Engine:new(Driver, host, port) engine.options.script_name = SCRIPT_NAME local result status, result = engine:start() for _, sock in pairs(ConnectionPool) do sock:close() end return result end