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|
---
-- A minimal RDP (Remote Desktop Protocol) library. Currently has functionality to determine encryption
-- and cipher support.
--
--
-- @author Patrik Karlsson <patrik@cqure.net>
-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
--
local nmap = require("nmap")
local stdnse = require("stdnse")
local string = require "string"
local asn1 = require "asn1"
_ENV = stdnse.module("rdp", stdnse.seeall)
-- Server Core Data 2.2.1.4.2
PROTO_VERSION = {
[0x00080001] = " RDP 4.0 server",
[0x00080004] = " RDP 5.x, 6.x, 7.x, or 8.x server",
[0x00080005] = " RDP 10.0 server",
[0x00080006] = " RDP 10.1 server",
[0x00080007] = " RDP 10.2 server",
[0x00080008] = " RDP 10.3 server",
[0x00080009] = " RDP 10.4 server",
[0x0008000A] = " RDP 10.5 server",
[0x0008000B] = " RDP 10.6 server",
[0x0008000C] = " RDP 10.7 server",
}
-- T.125 Result enumerated type
CONNECT_RESPONSE_RESULT = {
[ 0] = "rt-successful",
[ 1] = "rt-domain-merging",
[ 2] = "rt-domain-not-hierarchical",
[ 3] = "rt-no-such-channel",
[ 4] = "rt-no-such-domain",
[ 5] = "rt-no-such-user",
[ 6] = "rt-not-admitted",
[ 7] = "rt-other-user-id",
[ 8] = "rt-parameters-unacceptable",
[ 9] = "rt-token-not-available",
[10] = "rt-token-not-possessed",
[11] = "rt-too-many-channels",
[12] = "rt-too-many-tokens",
[13] = "rt-too-many-users",
[14] = "rt-unspecified-failure",
[15] = "rt-user-rejected",
}
-- requestedProtocols - flag - RDP_NEG_REQ - MS-RDPBCGR 2.2.1.1.1
PROTOCOL_RDP = 0 -- Standard RDP Security
PROTOCOL_SSL = 1 -- TLS 1.0, 1.1, 1.2
PROTOCOL_HYBRID = 2 -- CredSSP (NLA). TLS flag should be set as well
PROTOCOL_RDSTLS = 4 -- RDSTLS
PROTOCOL_HYBRID_EX = 8 -- CredSSP (NLA) with Early User Auth PDU
Packet = {
TPKT = {
new = function(self, data)
local o = { data = tostring(data), version = 3 }
setmetatable(o, self)
self.__index = self
return o
end,
__tostring = function(self)
return string.pack(">BBI2",
self.version,
self.reserved or 0,
(self.data and #self.data + 4 or 4))
..self.data
end,
parse = function(data)
local tpkt = Packet.TPKT:new()
local pos
tpkt.version, tpkt.reserved, tpkt.length, pos = string.unpack(">BBI2", data)
tpkt.data = data:sub(pos)
return tpkt
end
},
ITUT = {
new = function(self, code, data)
local o = { data = tostring(data), code = code }
setmetatable(o, self)
self.__index = self
return o
end,
parse = function(data)
local itut = Packet.ITUT:new()
local pos
itut.length, itut.code, pos = string.unpack("BB", data)
if ( itut.code == 0xF0 ) then
-- X.224 - Data TPDU (DT)
itut.eot, pos = string.unpack("B", data, pos)
elseif ( itut.code == 0xD0 ) then
-- X.224 - Connection Confirm (CC)
itut.dstref, itut.srcref, itut.class, pos = string.unpack(">I2I2B", data, pos)
end
itut.data = data:sub(pos)
return itut
end,
__tostring = function(self)
local len, eot
if self.code == 0xF0 then
eot = "\x80"
len = 2
else
eot = ""
len = #self.data + 1
end
local data = string.pack("BB",
len,
self.code or 0)
.. eot
.. self.data
return data
end,
},
ConfCreateResponse = {
new = function(self)
local o = {}
setmetatable(o, self)
self.__index = self
return o
end,
parse = function(data)
local tag_decoder = {}
tag_decoder["\x0A"] = function( self, encStr, elen, pos )
return self.decodeInt(encStr, elen, pos)
end
local ccr = Packet.ConfCreateResponse:new()
local decoder = asn1.ASN1Decoder:new()
decoder:registerTagDecoders( tag_decoder )
local _, pos = decoder.decodeLength(data, 3)
local response_result, userdata
response_result, pos = decoder:decode(data, pos)
ccr.result = CONNECT_RESPONSE_RESULT[response_result]
ccr.calledConnectId, pos = decoder:decode(data, pos)
-- T.125 DomainParameters SEQUENCE
-- Not interested in its values now, just need to correctly parse
-- the block so we can arrive at userData
_, pos = decoder:decode(data, pos)
-- T.125 userData OCTO string
userdata, _ = decoder:decode(data, pos)
if userdata == nil then
return ccr
end
-- Hackery to avoid writing ASN.1 PER decoding. Skip over fixed length
-- T.124 ConnectData header. Decode the length since it can be multiple
-- bytes. Drops us where we need to be.
_, pos = asn1.ASN1Decoder.decodeLength(userdata, 22 )
local block_type, block_len
while userdata:len() > pos do
block_type, block_len = string.unpack("<I2I2", userdata, pos)
if block_type == 0x0c01 then
-- 2.2.1.42 Server Core Data - TS_UD_SC_CORE
local proto_ver = string.unpack("<I4",userdata, pos + 4)
ccr.proto_version = ("RDP Protocol Version: %s"):format(PROTO_VERSION[proto_ver] or "Unknown")
elseif block_type == 0x0c02 then
-- 2.2.1.4.3 Server Security Data - TS_UD_SC_SEC1
ccr.enc_level = string.unpack("B", userdata, pos + 8)
ccr.enc_cipher= string.unpack("B", userdata, pos + 4)
end
pos = pos + block_len
end
return ccr
end,
},
}
Request = {
ConnectionRequest = {
new = function(self, proto)
local o = { proto = proto }
setmetatable(o, self)
self.__index = self
return o
end,
__tostring = function(self)
local cookie = "mstshash=nmap"
local data = string.pack(">I2I2B",
0x0000, -- dst reference
0x0000, -- src reference
0x00) -- class and options
.. ("Cookie: %s\r\n"):format(cookie)
if ( self.proto ) then
data = data .. string.pack("<BBI2I4",
0x01, -- TYPE_RDP_NEG_REQ
0x00, -- flags
0x0008, -- length
self.proto -- protocol
)
end
return tostring(Packet.TPKT:new(Packet.ITUT:new(0xE0, data)))
end
},
MCSConnectInitial = {
new = function(self, cipher, server_proto)
local o = { cipher = cipher, server_proto = server_proto }
setmetatable(o, self)
self.__index = self
return o
end,
__tostring = function(self)
local data = stdnse.fromhex(
"7f 65" .. -- BER: Application-Defined Type = APPLICATION 101,
"82 01 94" .. -- BER: Type Length = 404 bytes
"04 01 01" .. -- Connect-Initial::callingDomainSelector
"04 01 01" .. -- Connect-Initial::calledDomainSelector
"01 01 ff" .. -- Connect-Initial::upwardFlag = TRUE
"30 19" .. -- Connect-Initial::targetParameters (25 bytes)
"02 01 22" .. -- DomainParameters::maxChannelIds = 34
"02 01 02" .. -- DomainParameters::maxUserIds = 2
"02 01 00" .. -- DomainParameters::maxTokenIds = 0
"02 01 01" .. -- DomainParameters::numPriorities = 1
"02 01 00" .. -- DomainParameters::minThroughput = 0
"02 01 01" .. -- DomainParameters::maxHeight = 1
"02 02 ff ff" .. -- DomainParameters::maxMCSPDUsize = 65535
"02 01 02" .. -- DomainParameters::protocolVersion = 2
"30 19" .. -- Connect-Initial::minimumParameters (25 bytes)
"02 01 01" .. -- DomainParameters::maxChannelIds = 1
"02 01 01" .. -- DomainParameters::maxUserIds = 1
"02 01 01" .. -- DomainParameters::maxTokenIds = 1
"02 01 01" .. -- DomainParameters::numPriorities = 1
"02 01 00" .. -- DomainParameters::minThroughput = 0
"02 01 01" .. -- DomainParameters::maxHeight = 1
"02 02 04 20" .. -- DomainParameters::maxMCSPDUsize = 1056
"02 01 02" .. -- DomainParameters::protocolVersion = 2
"30 1c" .. -- Connect-Initial::maximumParameters (28 bytes)
"02 02 ff ff" .. -- DomainParameters::maxChannelIds = 65535
"02 02 fc 17" .. -- DomainParameters::maxUserIds = 64535
"02 02 ff ff" .. -- DomainParameters::maxTokenIds = 65535
"02 01 01" .. -- DomainParameters::numPriorities = 1
"02 01 00" .. -- DomainParameters::minThroughput = 0
"02 01 01" .. -- DomainParameters::maxHeight = 1
"02 02 ff ff" .. -- DomainParameters::maxMCSPDUsize = 65535
"02 01 02" .. -- DomainParameters::protocolVersion = 2
"04 82 01 33" .. -- Connect-Initial::userData (307 bytes)
"00 05" .. -- object length = 5 bytes
"00 14 7c 00 01" .. -- object
"81 2a" .. -- ConnectData::connectPDU length = 42 bytes
"00 08 00 10 00 01 c0 00 44 75 63 61 81 1c" .. -- PER encoded (ALIGNED variant of BASIC-PER) GCC Conference Create Request PDU
"01 c0 d8 00" .. -- TS_UD_HEADER::type = CS_CORE (0xc001), length = 216 bytes
"04 00 08 00" .. -- TS_UD_CS_CORE::version = 0x0008004
"00 05" .. -- TS_UD_CS_CORE::desktopWidth = 1280
"20 03" .. -- TS_UD_CS_CORE::desktopHeight = 1024
"01 ca" .. -- TS_UD_CS_CORE::colorDepth = RNS_UD_COLOR_8BPP (0xca01)
"03 aa" .. -- TS_UD_CS_CORE::SASSequence
"09 04 00 00" .. -- TS_UD_CS_CORE::keyboardLayout = 0x409 = 1033 = English (US)
"28 0a 00 00" .. -- TS_UD_CS_CORE::clientBuild = 2600
"45 00 4d 00 50 00 2d 00 4c 00 41 00 50 00 2d 00 " ..
"30 00 30 00 31 00 34 00 00 00 00 00 00 00 00 00 " .. -- TS_UD_CS_CORE::clientName = EMP-LAP-0014
"04 00 00 00" .. -- TS_UD_CS_CORE::keyboardType
"00 00 00 00" .. -- TS_UD_CS_CORE::keyboardSubtype
"0c 00 00 00" .. -- TS_UD_CS_CORE::keyboardFunctionKey
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " ..
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " ..
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " ..
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " .. -- TS_UD_CS_CORE::imeFileName = ""
"01 ca" .. -- TS_UD_CS_CORE::postBeta2ColorDepth = RNS_UD_COLOR_8BPP (0xca01)
"01 00" .. -- TS_UD_CS_CORE::clientProductId
"00 00 00 00" .. -- TS_UD_CS_CORE::serialNumber
"18 00" .. -- TS_UD_CS_CORE::highColorDepth = 24 bpp
"07 00" .. -- TS_UD_CS_CORE::supportedColorDepths = 24 bpp
"01 00" .. -- TS_UD_CS_CORE::earlyCapabilityFlags
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " ..
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " ..
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " ..
"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " .. -- TS_UD_CS_CORE::clientDigProductId
"00" .. -- TS_UD_CS_CORE::connectionType = 0 (not used as RNS_UD_CS_VALID_CONNECTION_TYPE not set)
"00") -- TS_UD_CS_CORE::pad1octet
-- TS_UD_CS_CORE::serverSelectedProtocol
.. string.pack("<I4", self.server_proto or 0) .. stdnse.fromhex(
"04 c0 0c 00" .. -- TS_UD_HEADER::type = CS_CLUSTER (0xc004), length = 12 bytes
"09 00 00 00" .. -- TS_UD_CS_CLUSTER::Flags = 0x0d
"00 00 00 00" .. -- TS_UD_CS_CLUSTER::RedirectedSessionID
"02 c0 0c 00") -- TS_UD_HEADER::type = CS_SECURITY (0xc002), length = 12 bytes
-- "1b 00 00 00" .. -- TS_UD_CS_SEC::encryptionMethods
.. string.pack("<I4", self.cipher or 0) .. stdnse.fromhex(
"00 00 00 00" .. -- TS_UD_CS_SEC::extEncryptionMethods
"03 c0 2c 00" .. -- TS_UD_HEADER::type = CS_NET (0xc003), length = 44 bytes
"03 00 00 00" .. -- TS_UD_CS_NET::channelCount = 3
"72 64 70 64 72 00 00 00" .. -- CHANNEL_DEF::name = "rdpdr"
"00 00 80 80" .. -- CHANNEL_DEF::options = 0x80800000
"63 6c 69 70 72 64 72 00" .. -- CHANNEL_DEF::name = "cliprdr"
"00 00 a0 c0" .. -- CHANNEL_DEF::options = 0xc0a00000
"72 64 70 73 6e 64 00 00" .. -- CHANNEL_DEF::name = "rdpsnd"
"00 00 00 c0" -- CHANNEL_DEF::options = 0xc0000000
)
return tostring(Packet.TPKT:new(Packet.ITUT:new(0xF0, data)))
end
},
}
Response = {
ConnectionConfirm = {
new = function(self)
local o = { }
setmetatable(o, self)
self.__index = self
return o
end,
parse = function(data)
local cc = Response.ConnectionConfirm:new()
cc.tpkt = Packet.TPKT.parse(data)
cc.itut = Packet.ITUT.parse(cc.tpkt.data)
return cc
end,
},
MCSConnectResponse = {
new = function(self)
local o = { }
setmetatable(o, self)
self.__index = self
return o
end,
parse = function(data)
local cr = Response.MCSConnectResponse:new()
cr.tpkt = Packet.TPKT.parse(data)
cr.itut = Packet.ITUT.parse(cr.tpkt.data)
if ( cr.itut.code == 0xF0 ) then
-- X.224 - Data TPDU (DT)
cr.ccr = Packet.ConfCreateResponse.parse(cr.itut.data)
end
return cr
end
}
}
Comm = {
-- Creates a new Comm instance
-- @param host table
-- @param port table
-- @return o instance of Comm
new = function(self, host, port)
local o = { host = host, port = port }
setmetatable(o, self)
self.__index = self
return o
end,
-- Connect to the server
-- @return status true on success, false on failure
-- @return err string containing error message, if status is false
connect = function(self)
self.socket = nmap.new_socket()
self.socket:set_timeout(5000)
if ( not(self.socket:connect(self.host, self.port)) ) then
return false, "Failed connecting to server"
end
return true
end,
-- Close the connection to the server
-- @return status true on success, false on failure
close = function(self)
return self.socket:close()
end,
-- Sends a message to the server
-- @param pkt an instance of Request.*
-- @return status true on success, false on failure
-- @return err string containing error message, if status is false
send = function(self, pkt)
return self.socket:send(tostring(pkt))
end,
-- Receives a message from the server
-- @return status true on success, false on failure
-- @return err string containing error message, if status is false
recv = function(self)
return self.socket:receive()
end,
-- Sends a message to the server and receives the response
-- @param pkt an instance of Request.*
-- @return status true on success, false on failure
-- @return err string containing error message, if status is false
-- pkt instance of Response.* on success
exch = function(self, pkt)
local status, err = self:send(pkt)
if ( not(status) ) then
return false, err
end
local _, data = self:recv()
if ( #data< 5 ) then
return false, "Packet too short"
end
local itut_code = string.byte(data, 6)
if ( itut_code == 0xD0 ) then
stdnse.debug2("RDP: Received ConnectionConfirm response")
return true, Response.ConnectionConfirm.parse(data)
elseif ( itut_code == 0xF0 ) then
return true, Response.MCSConnectResponse.parse(data)
elseif itut_code ~= nil then
stdnse.debug1(("comm:exch - Unknown itut_code: %s"):format(itut_code))
end
return false, "Received unhandled packet"
end,
}
return _ENV;
|