Nokia/Alcatel-Lucent router backup configuration tool

nokia-router-cfg-tool.py

#!/usr/bin/env python3


#
# Nokia/Alcatel-Lucent router backup configuration tool
# G2425 support added by rajkosto on 20/11/2022
# XS-2426G-B support added by rajkosto on 28/02/2023
#
# Features:
# - Unpack/repack .cfg files generated from the backup and restore functionnality
#   in order to modify the full router configuration
# - Decrypt/encrypt the passwords/secret values present in the configuration
#
# Original author blog post: https://0x41.cf/reversing/2019/10/08/unlocking-nokia-g240wa.html
#
# Released under the MIT License (http://opensource.org/licenses/MIT)
# Copyright (c) Sami Alaoui Kendil (thedroidgeek)
# Copyright (c) Rajko Stojadinovic (rajkosto)
#


import io
import sys
import zlib
import struct
import base64
import binascii
import datetime
import hashlib
import secrets


big_endian = True
encrypted_cfg = False


def u32(val):
    return struct.unpack('>I' if big_endian else '<I', val)[0]

def p32(val):
    return struct.pack('>I' if big_endian else '<I', val)

def checkendian(cfg):
    if (cfg[0:4] == b'\x00\x12\x31\x23'):
        return True
    elif (cfg[0:4] == b'\x23\x31\x12\x00'):
        return False
    else:
        return None


class RouterCrypto:

    def __init__(self):

        from Crypto.Cipher import AES

        # key and IV for AES
        key = '3D A3 73 D7 DC 82 2E 2A 47 0D EC 37 89 6E 80 D7 2C 49 B3 16 29 DD C9 97 35 4B 84 03 91 77 9E A4'
        iv  = 'D0 E6 DC CD A7 4A 00 DF 76 0F C0 85 11 CB 05 EA'

        # create AES-128-CBC cipher
        self.cipher = AES.new(bytes(bytearray.fromhex(key)), AES.MODE_CBC, bytes(bytearray.fromhex(iv)))

    def decrypt(self, data):

        output = self.cipher.decrypt(data)

        # verify and remove PKCS#7 padding
        padLen = ord(output[-1:])
        if padLen <= 0 or padLen > 16: #cannot be 0 or > blocksize
            return None

        padBytes = output[-padLen:]
        validPad = all(padByte == padLen for padByte in padBytes)
        if validPad:
            return output[:-padLen]
        else:
            return None

    def encrypt(self, data):

        # add PKCS#7 padding for 128-bit AES
        pad_num = (16 - (len(data) % 16))
        data += chr(pad_num).encode() * pad_num

        return self.cipher.encrypt(data)

class PKCSPassCrypto(RouterCrypto):

    def __init__(self, pkcsPass, pkcsSalt):

        from Crypto.Cipher import AES
        from hashlib import pbkdf2_hmac

        keyLen = 32 #AES-256
        ivLen = 16 #AES blocksize

        if not isinstance(pkcsPass, bytes): 
            pkcsPass = pkcsPass.encode()

        pkcs = pbkdf2_hmac('sha256', pkcsPass, pkcsSalt, 10, dklen=keyLen+ivLen)
        keyBytes = pkcs[:keyLen]
        ivBytes = pkcs[keyLen:]
        self.cipher = AES.new(keyBytes, AES.MODE_CBC, ivBytes)

#G2425 and newer config pkcs password
PKCSPasswords = ["S23l7nZm47XyMGs6y6oJpN9CR4nbfIZHJ4VRwp7HcdV6o2YvUmeNYFlz08Otwz78"]

#
# unpack xml from cfg
#

if (len(sys.argv) == 3 and sys.argv[1] == '-u'):

    # line feed
    print('')

    # read the cfg file
    cf = open(sys.argv[2], 'rb')
    cfg_data = cf.read()

    # check cfg file magic (0x123123) and determine endianness
    big_endian = checkendian(cfg_data)

    if big_endian == None:

        # check if config is encrypted
        decrypted = None
        try:
            # decrypt and check validity
            decrypted = RouterCrypto().decrypt(cfg_data)
            big_endian = checkendian(decrypted)
        except ValueError:
            pass

        # if decryption failed, or still invalid, bail out
        if big_endian == None:
            print('invalid cfg file/magic :(\n')
            exit()

        # set decrypted cfg buffer and encryption flag
        print('-> encrypted cfg detected')
        cfg_data = decrypted
        encrypted_cfg = True

    # log endianness
    if big_endian:
        print('-> big endian CPU detected')
    else:
        print('-> little endian CPU detected')

    # get the size of the compressed data
    data_size = u32(cfg_data[0x04:0x08])

    large_header = False
    if data_size == 0:
        data_size = u32(cfg_data[0x08:0x0C])
        large_header = True

    if data_size == 0:
        print('\nERROR: config data size is 0!\n')
        exit()

    # get fw_magic (unknown, could be fw version/compile time, hw serial number, etc.)
    fw_magic = 0
    if large_header:
        fw_magic = u32(cfg_data[0x20:0x24])
    else:
        fw_magic = u32(cfg_data[0x10:0x14])
    print('-> fw_magic = ' + hex(fw_magic))

    # get the compressed data
    compressed = []
    if large_header:
        compressed = cfg_data[0x28 : 0x28 + data_size]
    else:
        compressed = cfg_data[0x14 : 0x14 + data_size]

    # get the checksum of the compressed data 
    checksum = 0
    if large_header:
        checksum = u32(cfg_data[0x10:0x14])
    else:
        checksum = u32(cfg_data[0x08:0x0C])

    # verify the checksum
    if (binascii.crc32(compressed) & 0xFFFFFFFF != checksum):
        print('\nCRC32 checksum failed :(\n')
        exit()

    uncomp_size = 0
    if large_header:
        uncomp_size = u32(cfg_data[0x18:0x1C])
    else:
        uncomp_size = u32(cfg_data[0x0C:0x10])

    # unpack the config
    xml_data = None
    try:
        xml_data = zlib.decompress(compressed)
        pkcsPass = None
    except zlib.error:
        encData = None
        pkcsSalt = None
        tryPasswords = []
        if compressed[0] == 0xFF: #pkcs encrypted payload
            tryPasswords = PKCSPasswords
            with io.BytesIO(compressed) as payload:
                payload.seek(1)
                pkcsSalt = payload.read(8)
                encData = payload.read()

        for currPass in tryPasswords:
            decryptor = PKCSPassCrypto(currPass,pkcsSalt)
            compressed = decryptor.decrypt(encData)
            if compressed is None: #pkcs padding verification failed, key is wrong
                continue

            try:
                xml_data = zlib.decompress(compressed)
                pkcsPass = currPass
            except zlib.error:
                pass

        if xml_data is None:
            if len(tryPasswords):
                raise RuntimeError('Exhausted all known encryption passwords')
            else:
                raise

    if len(xml_data) != uncomp_size:
        print('WARNING: uncompressed size does not match value in header!')

    # output the xml file
    out_filename = 'config-%s.xml' % datetime.datetime.now().strftime('%d%m%Y-%H%M%S')
    if xml_data[0] != ord('<'):
        out_filename = out_filename.replace('.xml','.ini')

    of = open(out_filename, 'wb')
    of.write(xml_data)

    print('\nunpacked as: ' + out_filename)

    recompInfo = ('-pb' if big_endian else '-pl')
    if large_header:
        recompInfo += '64'
    if encrypted_cfg or pkcsPass:
        recompInfo += 'e'
        if pkcsPass:
            recompInfo += pkcsPass

    print('\n# repack with:')
    print('%s %s %s %s\n' % (sys.argv[0], recompInfo, out_filename, hex(fw_magic)))

    cf.close()
    of.close()
#
# generate cfg from xml
#

elif (len(sys.argv) == 4 and (sys.argv[1][:3] == '-pb' or sys.argv[1][:3] == '-pl')):

    fw_magic = 0

    try:
        # parse hex string
        fw_magic = int(sys.argv[3], 16)
        # 32-bit check
        p32(fw_magic)
    except:
        print('\ninvalid magic value specified (32-bit hex)\n')
        exit()

    big_endian = sys.argv[1][:3] == '-pb'
    large_header = False
    param_len = 3
    if sys.argv[1][3:5] == '64':
        large_header = True
        param_len += 2
    elif sys.argv[1][3:5] == '32':
        large_header = False
        param_len += 2

    encrypted_cfg = False
    if len(sys.argv[1]) > param_len and sys.argv[1][param_len] == 'e':
        encrypted_cfg = True
        param_len += 1

    pkcsPass = None
    if encrypted_cfg and len(sys.argv[1]) > param_len:
        pkcsPass = sys.argv[1][param_len:]
        encrypted_cfg = False

    out_filename = 'config-%s.cfg' % datetime.datetime.now().strftime('%d%m%Y-%H%M%S')

    # read the xml file
    xf = open(sys.argv[2], 'rb')
    xml_data = xf.read()
    xf.close()

    # compress using default zlib compression
    compressed = zlib.compress(xml_data)

    # pkcs encrypt the inner data if needed
    extraDecompLen = 1 #non pkcs encrypted configs have +1 to decomp len
    if pkcsPass is not None:
        extraDecompLen = 0
        with io.BytesIO() as payload:
            payload.write(b'\xFF')
            pkcsSalt = secrets.token_bytes(8)
            payload.write(pkcsSalt)
            cryptor = PKCSPassCrypto(pkcsPass,pkcsSalt)
            payload.write(cryptor.encrypt(compressed))
            compressed = payload.getvalue()

    ## construct the header ##
    # magic
    cfg_data = p32(0x123123)
    if large_header:
        cfg_data += p32(0)
    # size of compressed data
    cfg_data += p32(len(compressed))
    if large_header:
        cfg_data += p32(0)
    # crc32 checksum
    cfg_data += p32(binascii.crc32(compressed) & 0xFFFFFFFF)
    if large_header:
        cfg_data += p32(0)
    # size of xml file
    cfg_data += p32(len(xml_data) + extraDecompLen)
    if large_header:
        cfg_data += p32(0)
    # fw_magic
    cfg_data += p32(fw_magic)
    if large_header:
        cfg_data += p32(0)

    # add the compressed xml
    cfg_data += compressed

    # encrypt overall file if necessary
    if encrypted_cfg:
        cfg_data = RouterCrypto().encrypt(cfg_data)

    # write the cfg file
    of = open(out_filename, 'wb')
    of.write(cfg_data)
    of.close()

    print('\npacked as: ' + out_filename + '\n')


#
# decrypt/encrypt secret value
#

elif (len(sys.argv) == 3 and (sys.argv[1] == '-d' or sys.argv[1] == '-e')):

    decrypt_mode = sys.argv[1] == '-d'

    if decrypt_mode:

        # base64 decode + AES decrypt
        print('\ndecrypted: ' + RouterCrypto().decrypt(base64.b64decode(sys.argv[2])).decode('UTF-8') + '\n')

    else:

        # AES encrypt + base64 encode
        print('\nencrypted: ' + base64.b64encode(RouterCrypto().encrypt(sys.argv[2].encode())).decode('UTF-8') + '\n')


else:

    print('\n#\n# Nokia/Alcatel-Lucent router backup configuration tool\n#\n')
    print('# unpack (cfg to xml)\n')
    print(sys.argv[0] + ' -u config.cfg\n')
    print('# pack (xml to cfg)\n')
    print(sys.argv[0] + ' -pb  config.xml 0x13377331 # big endian, no encryption, fw_magic = 0x13377331')
    print(sys.argv[0] + ' -pl  config.xml 0x13377331 # little endian, ...')
    print(sys.argv[0] + ' -pbe config.xml 0x13377331 # big endian, with encryption, ...')
    print(sys.argv[0] + ' -ple config.xml 0x13377331 # ...\n')
    print('# decrypt/encrypt secret values within xml (ealgo="ab")\n')
    print(sys.argv[0] + ' -d OYdLWUVDdKQTPaCIeTqniA==')
    print(sys.argv[0] + ' -e admin\n')

Reverse engineered the firmware, it's in an encrypted file in /etc, keys for which differ for each fw ver, but this password is still consistent across firmwares and even newer models, if they change it I'll have to obtain newer firmware and reverse engineer it again

Hi @rajkosto !

Thank you for the great work done! I just wanted to ask you for a small guide/how-to about the process of PKCSPasswords extraction
from newer Nokia firmware (e.g. 3FE49568IJJK06(1.2203.406))... I have already dumped and extracted the firmware from a
locked Nokia ONT router (G-1425G-A, provided by my ISP) and have found the "config_encryption.cfg" file, but the script posted here
was not able to decrypt it and now I do not know how to move forward...
Can you, please, help with the reverse engineering process to find the new/suitable PKCSPasswords?
Also, the magic value/header in my config file is different (Hex 24 41 12 00). After correcting that (to Hex 23 31 12 00), I get this error:

---

Traceback (most recent call last):
File "C:\Users\taronhov\Downloads\mtd6_mtd7\nokia-router-cfg-tool.py", line 205, in
xml_data = zlib.decompress(compressed)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
zlib.error: Error -3 while decompressing data: incorrect header check

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "C:\Users\taronhov\Downloads\mtd6_mtd7\nokia-router-cfg-tool.py", line 232, in
raise RuntimeError('Exhausted all known encryption passwords')
RuntimeError: Exhausted all known encryption passwords

---

Thanks!

C:\Users\Yan\Downloads\Python 3>python nokia-router-cfg-tool.py -u config.cfg

-> little endian CPU detected
-> fw_magic = 0xffffffff

unpacked as: config-04112024-131752.xml

repack with:

nokia-router-cfg-tool.py -pleS23l7nZm47XyMGs6y6oJpN9CR4nbfIZHJ4VRwp7HcdV6o2YvUmeNYFlz08Otwz78 config-04112024-131752.xml 0xffffffff

C:\Users\Yan\Downloads\Python 3>nokia-router-cfg-tool.py -pleS23l7nZm47XyMGs6y6oJpN9CR4nbfIZHJ4VRwp7HcdV6o2YvUmeNYFlz08Otwz78 config-04112024-131752.xml 0xffffffff

C:\Users\Yan\Downloads\Python 3>
[main 2024-11-04T17:18:00.481Z] update#setState idle
[main 2024-11-04T17:18:01.953Z] Extension host with pid 5492 exited with code: 0, signal: unknown.

Hello, I am facing this issue trying to run the script recently. Any idea on how to fix it? It just opens VScode when I try repacking

Reverse engineered the firmware, it's in an encrypted file in /etc, keys for which differ for each fw ver, but this password is still consistent across firmwares and even newer models, if they change it I'll have to obtain newer firmware and reverse engineer it again

Hi @rajkosto !

Thank you for the great work done! I just wanted to ask you for a small guide/how-to about the process of PKCSPasswords extraction from newer Nokia firmware (e.g. 3FE49568IJJK06(1.2203.406))... I have already dumped and extracted the firmware from a locked Nokia ONT router (G-1425G-A, provided by my ISP) and have found the "config_encryption.cfg" file, but the script posted here was not able to decrypt it and now I do not know how to move forward... Can you, please, help with the reverse engineering process to find the new/suitable PKCSPasswords? Also, the magic value/header in my config file is different (Hex 24 41 12 00). After correcting that (to Hex 23 31 12 00), I get this error:

Traceback (most recent call last): File "C:\Users\taronhov\Downloads\mtd6_mtd7\nokia-router-cfg-tool.py", line 205, in xml_data = zlib.decompress(compressed) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ zlib.error: Error -3 while decompressing data: incorrect header check

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "C:\Users\taronhov\Downloads\mtd6_mtd7\nokia-router-cfg-tool.py", line 232, in raise RuntimeError('Exhausted all known encryption passwords') RuntimeError: Exhausted all known encryption passwords

Thanks!

@taronhov
Can you share the process for extracting the firmware, my isp also upgraded similar software version and currently completely locked

@mytot
Hi, I have dumped the firmware from NAND IC (SPI memory chip), using a programmer...
Then used binwalk tol to examine it, and information provided here to extract mtd6 and mtd7 partitions (search these names here),
Then ubidump and ubi-readerr tools can be used to extract file-systems...
For other partitions you may want ot use sqashfs tools, etc.

Is it Possible to Convert this ONT GPON to EPON, I have there is Huawei ONU can be changed from GPON to EPON Updating Firmware

How to ru file mobile to termux

Hello sir @rajkosto,
I have a Nokia G2425G-A, with software version 3FE49362IJHK46 and hardware version 3FE48299DEAA. I downloaded the cfg file, decrypted it and edited it by following this yt video: https://youtu.be/yRFqs7CZGdg?si=UyJBETyQ-bbnRAPy but after i import it to the router, after reboot, i cant connect to the router anymore.

❯ python .\nokia-router-cfg-tool.py -u config.cfg

-> little endian CPU detected
-> fw_magic = 0xfffffffe
Traceback (most recent call last):
  File "nokia-router-cfg-tool.py", line 137, in <module>
    xml_data = zlib.decompress(compressed)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
zlib.error: Error -3 while decompressing data: incorrect header check

Hi there!
I have a Nokia G1425 from Telemex (Mexican ISP):
Chipset: MTK7528
Hardware: 3FE77771BEAA
Software: 3FE49568IJLJ07(1.2402.307)
Made in Nov 1, 2024.
This one does not let me decode, I get the dreaded:
-> little endian CPU detected
-> fw_magic = 0xfffffffe
Traceback (most recent call last):
File "/home/alisi/Downloads/nokia.py", line 137, in
xml_data = zlib.decompress(compressed)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
zlib.error: Error -3 while decompressing data: incorrect header check

I understand this is a decoding problem (I use Python and these libraries myself!) - The question here is, is there anything I can do to help the project/community to get this version of the firmware cracked?

I am more than willing to share my config.cfg with someone if needed; the credentials are non-relevant outside Telmex's network anyway:
https://drive.google.com/file/d/1NEp0mSZUdCpTH5w9QxykT00Mxmmgn1aj/view?usp=sharing

Thanks in advance!
-Alisi

Hello, sir @rajkosto . It worked, thanks! One thing though I want to set a static ARP.

When I run arp -s xxx xxx, it works, but after a reboot, I lose the changes.

Is there any way to persist this ARP?

I tried modifying init.d inside /etc, but /etc is not persisted. I also tried using cron, but nothing worked. If you have any ideas, I'd appreciate it. Thanks!

Hi there! I have a Nokia G1425 from Telemex (Mexican ISP): Chipset: MTK7528 Hardware: 3FE77771BEAA Software: 3FE49568IJLJ07(1.2402.307) Made in Nov 1, 2024. This one does not let me decode, I get the dreaded: -> little endian CPU detected -> fw_magic = 0xfffffffe Traceback (most recent call last): File "/home/alisi/Downloads/nokia.py", line 137, in xml_data = zlib.decompress(compressed) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ zlib.error: Error -3 while decompressing data: incorrect header check

I understand this is a decoding problem (I use Python and these libraries myself!) - The question here is, is there anything I can do to help the project/community to get this version of the firmware cracked?

I am more than willing to share my config.cfg with someone if needed; the credentials are non-relevant outside Telmex's network anyway: https://drive.google.com/file/d/1NEp0mSZUdCpTH5w9QxykT00Mxmmgn1aj/view?usp=sharing

Thanks in advance! -Alisi

I am getting this exact same error. I guess the new firmware changed something. Any luck? Here is my device info:

Device name
G-1425G-A
Vendor
Nokia
Serial Number:
ALCLFE08B0A0
Hardware Version:
3FE77771BEAA
Boot Version
Bootbase1.1-Jul-02-2024--22:11:45
Software Version:
3FE49568IJLJ07(1.2402.307)
Chipset
MTK7528
Lot Number
Nov 01 2024

PSA: You need pycryptodome library installed from pip for this script to work! Remove any previously installed crypto libraries.

PSA: You need pycryptodome library installed from pip for this script to work! Remove any previously installed crypto libraries.

That is already installed:
(base) cursor@MacBookPro temp % pip show pycryptodome
Name: pycryptodome
Version: 3.22.0
Summary: Cryptographic library for Python
Home-page: https://www.pycryptodome.org
Author: Helder Eijs
Author-email: [email protected]
License: BSD, Public Domain
Location: /Users/cursor/micromamba/lib/python3.9/site-packages

I can run the script with the -D option and get back: decrypted: admin

But when running with the -u option I get an error:

-> little endian CPU detected
-> fw_magic = 0xfffffffe
Traceback (most recent call last):
File "/Users/cursor/temp/nokia-router-cfg-tool.py", line 201, in
xml_data = zlib.decompress(compressed)
zlib.error: Error -3 while decompressing data: incorrect header check

From what I have read this is probably because of the firmware revision of the modem.