1 files changed, 140 insertions, 0 deletions
diff --git a/scripts/smtp-brute.nse b/scripts/smtp-brute.nse
new file mode 100644
index 0000000..ce0206c
--- /dev/null
+++ b/scripts/smtp-brute.nse
@@ -0,0 +1,140 @@
+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