Improve Your Site’s Security by Adding Two-Factor Authentication

July 1, 2015
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Identity theft and site compromises are all-too-common occurrences -- it seems a day rarely goes by without a news story detailing the latest batch of user passwords which have been compromised and publicly posted.

Passwords were first used in the 1960s when computers were shared among multiple people via time-sharing methods. Allowing multiple users on a single system required a way for users to prove they were who they claimed to be. As computer systems have grown more complex over the last 50 years, the same password concept has been baked into them as the core authentication method. That includes today’s Web sites, including those built using Drupal.

Why Better Protection Is Needed

Today, great lengths are taken to both protect a user’s password, and to protect users from choosing poor passwords. Drupal 7, for example, provided a major security upgrade in how passwords are stored. It also provides a visual indicator as to how complex a password is, in an attempt to describe how secure it might be.

The password_policy module is also available to enforce a matrix of requirements when a user chooses a password.

Both of these methods have helped to increase password security, but there’s still a fundamental problem. A password is simply asking a user to provide a value they know. To make this easier, the vast majority of people reuse the same password across multiple sites.

That means that no matter how well a site protects a user’s password, any other site that does a poor job could provide an attacker all they need to comprise your users’ accounts.

How Multi-Factor Authentication Works

Multi-Factor authentication is one way of solving this problem. There are three ways for a person to prove he is who he claims to be. These are known as factors and are the following:

  • Something you know - typically a password or passphrase
  • Something you have - a physical device such as a phone, ID, or keyfob
  • Something you are - biometric characteristics of the individual

Multi-factor authentication requests two or more of these factors. It makes it much more difficult for someone to impersonate a valid user. With it, if a user’s username and password were to be compromised, the attacker still wouldn’t be able to provide the user’s second form of authentication.

Here, we’ll be focusing on the most common multi-factor solution, something you know (existing password) and something you have (a cell phone).

This is the easiest method of multi-factor authentication, and is also known as two-factor authentication (TFA) because it uses two out of three factors. It’s already used by a large number of financial institutions, as well as large social websites such as Google, Facebook, and Twitter. Acquia implemented TFA for it’s users in 2014 as discussed in this blog post: Secure Acquia accounts with two-step verification and strong passwords.

How To Do It

A suite of modules are available for Drupal for multi-factor authentication. The Two-Factor Authentication module provides integration into Drupal’s existing user- and password-based authentication system. The module is built to be the base framework of any TFA solution, and so does not provide a second factor method itself. Instead the TFA Basic plugins module provides three plugins which are Google Authenticator, Trusted Device, and SMS using Twilio. TFA Basic can also be used as a guide to follow when creating custom plugins. You can find the documentation here: TFA plugin development.

You’ll find that it’s easy to protect your site and its users with TFA, and given its benefits, it’s a good idea to start now.

But before you do, check out the TFA documentation. Acquia Cloud Site Factory users can find documentation for configuring two-factor authentication for their accounts here.

For more advice, check out TFA tips from Drupal.org.

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