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local brute = require "brute"
local creds = require "creds"
local shortport = require "shortport"
local stdnse = require "stdnse"
local vnc = require "vnc"
description = [[
Performs brute force password auditing against VNC servers.
]]
---
-- @see realvnc-auth-bypass.nse
--
-- @args vnc-brute.bruteusers If set, allows the script to iterate over
-- usernames for auth types that require it (plain,
-- Apple Remote Desktop (30),
-- SASL (not supported), and ATEN) Default: false,
-- since most VNC auth types are password-only.
-- @usage
-- nmap --script vnc-brute -p 5900 <host>
--
-- @output
-- PORT STATE SERVICE REASON
-- 5900/tcp open vnc syn-ack
-- | vnc-brute:
-- | Accounts
-- |_ 123456 => Valid credentials
-- Summary
-- -------
-- x The Driver class contains the driver implementation used by the brute
-- library
--
--
--
-- Version 0.1
-- Created 07/12/2010 - 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 = {"intrusive", "brute"}
portrule = shortport.port_or_service(5901, "vnc", "tcp", "open")
Driver =
{
new = function(self, host, port)
local o = {}
setmetatable(o, self)
self.__index = self
o.host = host
o.port = port
return o
end,
connect = function( self )
self.vnc = vnc.VNC:new( self.host, self.port, brute.new_socket() )
return self.vnc:connect()
end,
--- Attempts to login to the VNC server
--
-- @param username string containing the login username
-- @param password string containing the login password
-- @return status, true on success, false on failure
-- @return brute.Error object on failure
-- creds.Account object on success
login = function( self, username, password )
local status, data = self.vnc:handshake()
if ( not(status) and ( data:match("Too many authentication failures") or
data:match("Your connection has been rejected.") ) ) then
local err = brute.Error:new( data )
err:setAbort( true )
return false, err
elseif ( not(status) ) then
local err = brute.Error:new( "VNC handshake failed" )
-- This might be temporary, set the retry flag
err:setRetry( true )
return false, err
end
status, data = self.vnc:login( username, password )
if ( status ) then
return true, creds.Account:new(username, password, creds.State.VALID)
elseif ( not( data:match("Authentication failed") ) ) then
local err = brute.Error:new( data )
-- This might be temporary, set the retry flag
err:setRetry( true )
return false, err
end
return false, brute.Error:new( "Incorrect password" )
end,
disconnect = function( self )
self.vnc:disconnect()
end,
check = function( self )
local vnc = vnc.VNC:new( self.host, self.port )
local status, data
status, data = vnc:connect()
if ( not(status) ) then
return stdnse.format_output( false, data )
end
status, data = vnc:handshake()
if ( not(status) ) then
return stdnse.format_output( false, data )
end
if ( vnc:supportsSecType(vnc.sectypes.NONE) ) then
return false, "No authentication required"
end
status, data = vnc:login( nil, "is_sec_mec_supported?" )
-- Check whether auth succeeded. This is most likely because one of the
-- NONE auth types was supported, since vnc.lua will just return true in that case.
if status then
return false, "No authentication required"
end
if ( data:match("The server does not support.*security type") ) then
return stdnse.format_output( false, " \n " .. data )
end
return true
end,
}
action = function(host, port)
local bruteusers = stdnse.get_script_args(SCRIPT_NAME .. ".bruteusers")
local status, result
local engine = brute.Engine:new(Driver, host, port )
engine.options.script_name = SCRIPT_NAME
engine.options.firstonly = true
engine.options:setOption( "passonly", not bruteusers )
status, result = engine:start()
return result
end
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