typisttech/wp-password-argon-two

Securely store WordPress user passwords in database with Argon2i hashing and SHA-512 HMAC using PHP's native functions.

0.2.1 2018-03-04 01:56 UTC

README

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Securely store WordPress user passwords in database with Argon2i hashing and SHA-512 HMAC using PHP's native functions.

Goal

Replace WordPress' phpass hasher with Argon2i hashing and SHA-512 HMAC.

Adopted from Mozilla secure coding guidelines:

  • Passwords stored in a database should using the hmac+argon2i function.

The purpose of HMAC and Argon2i storage is as follows:

  • Argon2i provides a hashing mechanism which can be configured to consume sufficient time to prevent brute forcing of hash values even with many computers
  • Argon2i can be easily adjusted at any time to increase the amount of work and thus provide protection against more powerful systems
  • The nonce(pepper) for the HMAC value is designed to be stored on the file system and not in the databases storing the password hashes. In the event of a compromise of hash values due to SQL injection, the nonce(pepper) will still be an unknown value since it would not be compromised from the file system. This significantly increases the complexity of brute forcing the compromised hashes considering both Argon2i and a large unknown nonce(pepper) value
  • The HMAC operation is simply used as a secondary defense in the event there is a design weakness with Argon2i that could leak information about the password or aid an attacker

Magic Moments

WP Password Argon Two just works when:

  • upgrading from extremely old WordPress versions

    user passwords were hashed with MD5

  • upgrading from recent WordPress versions

    user passwords were hashed with phpass hasher

  • upgrading from WP Password Bcrypt

    user passwords were hashed with Bcrypt

  • changing Argon2i options

  • using new pepper while moving the old ones into WP_PASSWORD_ARGON_TWO_FALLBACK_PEPPERS

User passwords will be rehashed during the next login.

Requirements

Do Your Homework

Don't blindly trust any random security guide/plugin on the scary internet - including this one!

Do your research:

PHP 7.2+ and compiled --with-password-argon2

To check whether PHP is compiled with Argon2:

# Good: Compiled with Argon2
➜ php -r 'print_r(get_defined_constants());' | grep -i argon
    [PASSWORD_ARGON2I] => 2
    [PASSWORD_ARGON2_DEFAULT_MEMORY_COST] => 1024
    [PASSWORD_ARGON2_DEFAULT_TIME_COST] => 2
    [PASSWORD_ARGON2_DEFAULT_THREADS] => 2
    [SODIUM_CRYPTO_PWHASH_ALG_ARGON2I13] => 1
    [SODIUM_CRYPTO_PWHASH_ALG_ARGON2ID13] => 2
    [SODIUM_CRYPTO_PWHASH_STRPREFIX] => $argon2id$

If you don't get the above output, either re-compile PHP 7.2+ with the flag --with-password-argon2 or:

  • Ubuntu
    ➜ sudo add-apt-repository ppa:ondrej/php
    ➜ sudo apt-get update
    ➜ sudo apt-get install php7.2
  • macOS
    ➜ brew update
    ➜ brew install php

Installation

Step 0

Read the whole readme and the source code before going any further.

Step 1

This plugin should not be installed as a normal WordPress plugin.

Option A: Via Composer Autoload (Recommended)

➜ composer require typisttech/wp-password-argon-two

Note: Files in src will be autoloaded by composer. WP Password Argon Two won't appear in the WP admin dashboard.

Option B: As a Must-use Plugin (Last Resort)

Manually copy wp-password-argon-two.php and the whole src directory into mu-plugins folder.

# Example
➜ tree ./wp-content/mu-plugins
./wp-content/mu-plugins
├── src
│   ├── Manager.php
│   ├── ManagerFactory.php
│   ├── PasswordLock.php
│   ├── Validator.php
│   ├── ValidatorInterface.php
│   ├── WordPressValidator.php
│   └── pluggable.php
└── wp-password-argon-two.php

Step 2

Option A - Use Constants

Add these constants into wp-config.php:

define('WP_PASSWORD_ARGON_TWO_PEPPER', 'your-long-and-random-pepper');
define('WP_PASSWORD_ARGON_TWO_FALLBACK_PEPPERS', []);
define('WP_PASSWORD_ARGON_TWO_OPTIONS', []);

Option B - Use Environment Variables

Defining the required constants in application code violates 12-factor principle. The typisttech/wp-password-argon-two-env package allows you to configure with environment variables.

Recommended for all Trellis users.

Usage

Pepper Migration

In some cases, you want to change the pepper without changing all user passwords.

define('WP_PASSWORD_ARGON_TWO_PEPPER', 'new-pepper');
define('WP_PASSWORD_ARGON_TWO_FALLBACK_PEPPERS', [
  'old-pepper-2',
  'old-pepper-1',
]);

During the next user login, his/her password will be rehashed with new-pepper.

Argon2i Options

Due to the variety of platforms PHP runs on, the cost factors are deliberately set low as to not accidentally exhaust system resources on shared or low resource systems when using the default cost parameters. Consequently, users should adjust the cost factors to match the system they're working on. As Argon2 doesn't have any "bad" values, however consuming more resources is considered better than consuming less. Users are encouraged to adjust the cost factors for the platform they're developing for.

-- PHP RFC

You can adjust the options via WP_PASSWORD_ARGON_TWO_OPTIONS:

// Example
define('WP_PASSWORD_ARGON_TWO_OPTIONS', [
    'memory_cost' => 1<<17, // 128 Mb
    'time_cost'   => 4,
    'threads'     => 3,
]);

Learn more about available options and picking appropriate options.

Uninstallation

You have to regenerate all user passwords after uninstallation because we can't rehash without knowing the passwords in plain text.

Frequently Asked Questions

What have you done with the passwords?

In a nutshell:

password_hash(
    hash_hmac('sha512', $userPassword, WP_PASSWORD_ARGON_TWO_PEPPER),
    PASSWORD_ARGON2I,
    WP_PASSWORD_ARGON_TWO_OPTIONS
);

Don't take my word for it. Read the source code!

I have installed this plugin. Does it mean my WordPress site is unhackable?

No website is unhackable.

To have a secure WordPress site, you have to keep all these up-to-date:

  • WordPress core
  • PHP
  • this plugin
  • all other WordPress themes and plugins
  • everything on the server
  • other security practices
  • your mindset

Did you reinvent the cryptographic functions?

Of course not! This plugin use PHP's native functions.

Repeat: Read the source code!

Pepper migration look great. Does it mean that I can keep as many pepper keys as I want?

In a sense, yes, you could do that. However, each pepper slows down the login process a little bit.

To test the worst case, log in with an incorrect password.

What if my pepper is compromised?

  1. Remove that pepper from WP_PASSWORD_ARGON_TWO_PEPPER and WP_PASSWORD_ARGON_TWO_FALLBACK_PEPPERS
  2. Regenerate all user passwords

Is pepper-ing perfect?

No! Read paragonie's explaination.

For those who can't stand with the drawbacks, use one of the alternatives instead.

Is WordPress' phpass hasher or Bcrypt insecure?

Both WordPress' phpass hasher and Bcrypt are secure. There is no emergent reason to upgrade.

Learn more about the reasons about not using WordPress' default.

Why use Argon2i over the others?

Argon2 password-based key derivation function is the winner of the Password Hashing Competition in July 2015, ranked better than Bcrypt and PBKDF2.

Argon2 comes with 3 different modes: Argon2d, Argon2i, Argon2id. Argon2i is the one for password hashing. See: https://crypto.stackexchange.com/a/49969

Does this plugin has 72-character limit like Bcrypt?

No. Read the test.

It looks awesome. Where can I find some more goodies like this?

This plugin isn't on wp.org. Where can I give a ⭐️⭐️⭐️⭐️⭐️ review?

Thanks!

Consider writing a blog post, submitting pull requests, donating or hiring me instead.

This plugin isn't on wp.org. Where can I make a complaint?

To be honest, I don't care.

If you really want to share your 1-star review, send me an email - in the first paragraph, state how many times I have told you to read the plugin source code.

Alternatives

Support!

Donate

Love WP Password Argon Two? Help me maintain it, a donation here can help with it.

Why don't you hire me?

Ready to take freelance WordPress jobs. Contact me via the contact form here or, via email info@typist.tech

Want to help in other way? Want to be a sponsor?

Contact: Tang Rufus

Developing

To setup a developer workable version you should run these commands:

$ composer create-project --keep-vcs --no-install typisttech/wp-password-argon-two:dev-master
$ cd wp-password-argon-two
$ composer install

To run the tests:

$ composer test

Feedback

Please provide feedback! We want to make this library useful in as many projects as possible. Please submit an issue and point out what you do and don't like, or fork the project and make suggestions. No issue is too small.

Change Log

Please see CHANGELOG for more information on what has changed recently.

Security

If you discover any security related issues, please email wp-password-argon-two@typist.tech instead of using the issue tracker.

Credits

WP Password Argon Two is a Typist Tech project and maintained by Tang Rufus, freelance developer for hire.

Full list of contributors can be found here.

License

The MIT License (MIT). Please see License File for more information.