description = [[ Determines which Security layer and Encryption level is supported by the RDP service. It does so by cycling through all existing protocols and ciphers. When run in debug mode, the script also returns the protocols and ciphers that fail and any errors that were reported. The script was inspired by MWR's RDP Cipher Checker http://labs.mwrinfosecurity.com/tools/2009/01/12/rdp-cipher-checker/ ]] --- -- @usage -- nmap -p 3389 --script rdp-enum-encryption -- -- @output -- PORT STATE SERVICE -- 3389/tcp open ms-wbt-server -- | rdp-enum-encryption: -- | Security layer -- | CredSSP: SUCCESS -- | Native RDP: SUCCESS -- | SSL: SUCCESS -- | RDP Encryption level: High -- | 128-bit RC4: SUCCESS -- |_ FIPS 140-1: SUCCESS -- author = "Patrik Karlsson" license = "Same as Nmap--See https://nmap.org/book/man-legal.html" local bin = require("bin") local nmap = require("nmap") local table = require("table") local shortport = require("shortport") local rdp = require("rdp") local stdnse = require("stdnse") categories = {"safe", "discovery"} portrule = shortport.port_or_service(3389, "ms-wbt-server") local function fail (err) return stdnse.format_output(false, err) end local function enum_protocols(host, port) local PROTOCOLS = { ["Native RDP"] = 0, ["SSL"] = 1, ["CredSSP"] = 3 } local ERRORS = { [1] = "SSL_REQUIRED_BY_SERVER", [2] = "SSL_NOT_ALLOWED_BY_SERVER", [3] = "SSL_CERT_NOT_ON_SERVER", [4] = "INCONSISTENT_FLAGS", [5] = "HYBRID_REQUIRED_BY_SERVER" } local res_proto = { name = "Security layer" } for k, v in pairs(PROTOCOLS) do local comm = rdp.Comm:new(host, port) if ( not(comm:connect()) ) then return false, fail("Failed to connect to server") end local cr = rdp.Request.ConnectionRequest:new(v) local status, response = comm:exch(cr) comm:close() if ( not(status) ) then return false, response end local pos, success = bin.unpack("C", response.itut.data) if ( success == 2 ) then table.insert(res_proto, ("%s: SUCCESS"):format(k)) elseif ( nmap.debugging() > 0 ) then local pos, err = bin.unpack("C", response.itut.data, 5) if ( err > 0 ) then table.insert(res_proto, ("%s: FAILED (%s)"):format(k, ERRORS[err] or "Unknown")) else table.insert(res_proto, ("%s: FAILED"):format(k)) end end end table.sort(res_proto) return true, res_proto end local function enum_ciphers(host, port) local CIPHERS = { { ["40-bit RC4"] = 1 }, { ["56-bit RC4"] = 8 }, { ["128-bit RC4"] = 2 }, { ["FIPS 140-1"] = 16 } } local ENC_LEVELS = { [0] = "None", [1] = "Low", [2] = "Client Compatible", [3] = "High", [4] = "FIPS Compliant", } local res_ciphers = {} local function get_ordered_ciphers() local i = 0 return function() i = i + 1 if ( not(CIPHERS[i]) ) then return end for k,v in pairs(CIPHERS[i]) do return k, v end end end for k, v in get_ordered_ciphers() do local comm = rdp.Comm:new(host, port) if ( not(comm:connect()) ) then return false, fail("Failed to connect to server") end local cr = rdp.Request.ConnectionRequest:new() local status, response = comm:exch(cr) if ( not(status) ) then break end local msc = rdp.Request.MCSConnectInitial:new(v) local status, response = comm:exch(msc) comm:close() if ( status ) then local pos, enc_level = bin.unpack("C", response.itut.data, 95 + 8) local pos, enc_cipher= bin.unpack("C", response.itut.data, 95 + 4) if ( enc_cipher == v ) then table.insert(res_ciphers, ("%s: SUCCESS"):format(k)) end res_ciphers.name = ("RDP Encryption level: %s"):format(ENC_LEVELS[enc_level] or "Unknown") elseif ( nmap.debugging() > 0 ) then table.insert(res_ciphers, ("%s: FAILURE"):format(k)) end end return true, res_ciphers end action = function(host, port) local result = {} local status, res_proto = enum_protocols(host, port) if ( not(status) ) then return res_proto end local status, res_ciphers = enum_ciphers(host, port) if ( not(status) ) then return res_ciphers end table.insert(result, res_proto) table.insert(result, res_ciphers) return stdnse.format_output(true, result) end