smtp-brute
NSE detection rule by Patrik Karlsson · Same as Nmap--See https://nmap.org/book/man-legal.html
Performs brute force password auditing against SMTP servers using either LOGIN, PLAIN, CRAM-MD5, DIGEST-MD5 or NTLM authentication.
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 <host>
--
-- @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 <patrik@cqure.net>
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