Error decrypting my Google Chrome passwords: 'utf-8' codec can't decode byte

Question

it happens that suddenly one day the autocomplete of Google Chrome stopped working. Look for my passwords in Settings---> Autocomplete---> Passwords and nothing, they weren't there! I did not delete anything, not even cookies... well. Researching on the internet I have used the Chromepassview and it only showed me the usernames and not the passwords. I analyzed the "Login Data" file with DB Browser SQLite and I see the password value in BLOB format. I have managed to convert the passwords to cipher text using the code in this link: https://ohyicong.medium.com/how-to-hack-chrome-password-with-python-1bedc167be3d but not knowing how to continue. I have now copied and pasted (from this link: https://github.com/ohyicong/decrypt-chrome-passwords/blob/main/decrypt_chrome_password.py ) the following python code:

import os
import re
import sys
import json
import base64
import sqlite3
import win32crypt
from Cryptodome.Cipher import AES
import shutil
import csv

#GLOBAL CONSTANT
CHROME_PATH_LOCAL_STATE = os.path.normpath(r"%s\AppData\Local\Google\Local State"%(os.environ['USERPROFILE']))
CHROME_PATH = os.path.normpath(r"%s\AppData\Local\Google\Chrome\User Data"%(os.environ['USERPROFILE']))

def get_secret_key():
    try:
        #(1) Get secretkey from chrome local state
        with open( CHROME_PATH_LOCAL_STATE, "r", encoding='utf-8') as f:
            local_state = f.read()
            local_state = json.loads(local_state)
        secret_key = base64.b64decode(local_state["os_crypt"]["encrypted_key"])
        #Remove suffix DPAPI
        secret_key = secret_key[5:] 
        secret_key = win32crypt.CryptUnprotectData(secret_key, None, None, None, 0)[1]
        return secret_key
    except Exception as e:
        print("%s"%str(e))
        print("[ERR] Chrome secretkey cannot be found")
        return None
    
def decrypt_payload(cipher, payload):
    return cipher.decrypt(payload)

def generate_cipher(aes_key, iv):
    return AES.new(aes_key, AES.MODE_GCM, iv)

def decrypt_password(ciphertext, secret_key):
    try:
        #(3-a) Initialisation vector for AES decryption
        initialisation_vector = ciphertext[3:15]
        #(3-b) Get encrypted password by removing suffix bytes (last 16 bits)
        #Encrypted password is 192 bits
        encrypted_password = ciphertext[15:-16]
        #(4) Build the cipher to decrypt the ciphertext
        cipher = generate_cipher(secret_key, initialisation_vector)
        decrypted_pass = decrypt_payload(cipher, encrypted_password)
        decrypted_pass = decrypted_pass.decode()  
        return decrypted_pass
    except Exception as e:
        print("%s"%str(e))
        print("[ERR] Unable to decrypt, Chrome version <80 not supported. Please check.")
        return ""
    
def get_db_connection(chrome_path_login_db):
    try:
        print(chrome_path_login_db)
        shutil.copy2(chrome_path_login_db, "Loginvault.db") 
        return sqlite3.connect("Loginvault.db")
    except Exception as e:
        print("%s"%str(e))
        print("[ERR] Chrome database cannot be found")
        return None
        
if __name__ == '__main__':
    try:
        #Create Dataframe to store passwords
        with open('decrypted_password.csv', mode='w', newline='', encoding='utf-8') as decrypt_password_file:
            csv_writer = csv.writer(decrypt_password_file, delimiter=',')
            csv_writer.writerow(["index","url","username","password"])
            #(1) Get secret key
            secret_key = get_secret_key()
            #Search user profile or default folder (this is where the encrypted login password is stored)
            folders = [element for element in os.listdir(CHROME_PATH) if re.search("^Profile*|^Default$",element)!=None]
            for folder in folders:
                #(2) Get ciphertext from sqlite database
                chrome_path_login_db = os.path.normpath(r"%s\%s\Login Data"%(CHROME_PATH,folder))
                conn = get_db_connection(chrome_path_login_db)
                if(secret_key and conn):
                    cursor = conn.cursor()
                    cursor.execute("SELECT action_url, username_value, password_value FROM logins")
                    for index,login in enumerate(cursor.fetchall()):
                        url = login[0]
                        username = login[1]
                        ciphertext = login[2]
                        if(url!="" and username!="" and ciphertext!=""):
                            #(3) Filter the initialisation vector & encrypted password from ciphertext 
                            #(4) Use AES algorithm to decrypt the password
                            decrypted_password = decrypt_password(ciphertext, secret_key)
                            print("Sequence: %d"%(index))
                            print("URL: %s\nUser Name: %s\nPassword: %s\n"%(url,username,decrypted_password))
                            print("*"*50)
                            #(5) Save into CSV 
                            csv_writer.writerow([index,url,username,decrypted_password])
                    #Close database connection
                    cursor.close()
                    conn.close()
                    #Delete temp login db
                    os.remove("Loginvault.db")
    except Exception as e:
        print("[ERR] "%str(e))

The problem is that the code only decrypts those passwords that I re-inserted after all will be deleted. For the rest it shows me the url, username, but the password is empty, like in the following message (2 examples here):

'utf-8' codec can't decode byte 0xef in position 2: invalid start byte
[ERR] Unable to decrypt, Chrome version <80 not supported. Please check.
Sequence: 32
URL: https://www.crunchyroll.com/
User Name: [email protected]
Password: 

or:

'utf-8' codec can't decode byte 0xde in position 0: invalid continuation byte
[ERR] Unable to decrypt, Chrome version <80 not supported. Please check.
Sequence: 63
URL: https://www.researchgate.net/signup.SignUpAccountBasics.html
User Name: [email protected]
Password: 

I use python at a basic level and I understand a little how AES encryption works, what could I do to solve it?

Answer 1

update your chrome version because this code won't work if the chrome version was less than 80