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Magic Links - Passwordless Authentication for the Future

By Brad McCarty

Magic Links - Passwordless Authentication for the Future

If you’re a developer, it’s your responsibility to keep up with the ever-evolving landscape of internet security. Today, we’re going to delve into an exciting facet of modern cybersecurity---magic links. Magic links are a method of passwordless authentication that has been gaining popularity. They allow users to access websites without typing a password or using an app, by simply clicking on a link sent directly to their email address.

In simplest terms, a magic link is a URL with an embedded unique token. They are sometimes included in a multi-factor authentication (MFA) approach. Clicking on the link authenticates the user. They can then access a particular service or application. It is similar in function to a one-time password (OTP) setup, but with less risk.

Magic links are a straightforward alternative to usernames and passwords. Instead of asking users to create and remember credentials, we send a one-time-use link to their registered email account. The link is unique, so it cannot be used by anyone else. It is also impossible for the user to lose because we can recover it from our servers at any time.

Because the link is sent via email, Slack, or even carrier pigeon, it is also potentially more secure than using SMS messages. While other messaging platforms can work with magic links, due to the ubiquity of email, most systems use that. The rest of this article will assume you are sending magic links over email. The concept was first introduced around 2010, and then picked up by major players such as Facebook and Microsoft. This approach has become popular because it’s easy for users and administrators alike.

The process starts when a user inputs their email address into a login form. The backend API service generates a unique token and attaches it to a URL, which we term as the “magic link.” This link is then sent to the user’s registered email. The user opens their email, clicks the magic link, which leads back to the application or service. The server then verifies the token and logs in the user.

By doing so, magic links leverage the security of the user’s email provider. If someone can access the magic link, they already have access to the user’s email. If the user’s email account is compromised, then they likely have bigger problems than someone accessing your service. The magic link is a one-time URL that can only be used once. This means that if someone steals a magic link that has already been used once, they cannot use it again. This means that the user gets the ease of logging in to your system without having to present a credential. But they still benefit from the security around the email account, including any protections the email provider has put in place or MFA the user has added.

User Experience (UX):

It’s no secret that users often struggle with password management. The average user is registered on dozens of online platforms, each requiring a unique password. Remembering these is often challenging, leading to frequent password resets, which further degrade user experience. Magic links simplify this process, requiring only access to an email account.

Security:

Despite being the standard for years, passwords are a known security weak point. Users often reuse passwords across platforms or opt for easy-to-remember (and easy-to-guess) options. By using magic links, we eliminate the risk of password reuse or theft. In addition, the temporary nature of magic links also acts as a security advantage, as each link expires after use or after a set period, whichever happens first. This prevents attackers from using them for malicious purposes.

Development Simplicity:

Implementing a secure password-based system can be a challenge. It involves creating secure password storage, implementing encryption, managing password resets, etc. In comparison, magic link systems can be simpler to implement and maintain.  They don’t require any changes to existing infrastructure, which makes them a good choice for small and medium businesses. In addition, they can be implemented with fewer resources than other security solutions such as software-based two-factor authentication (2FA) systems or hardware tokens.

While magic links provide an attractive alternative to traditional passwords and forgot password links, it’s crucial to consider potential drawbacks.

Email Account Dependence:

Magic links rely on the security of the user’s email account. If a user’s email account is compromised, all services using magic links are potentially at risk. It’s thus crucial to encourage users to protect their email accounts with strong security measures, like two-factor authentication. Also, some email providers will pre-fetch all links in all emails, which may expire magic links. Make sure you consider this in your implementation.

Phishing Attacks:

Users might be tricked into clicking on malicious links masquerading as magic links. Training users to identify genuine magic links and raising awareness about such threats is essential. 

Security:

If the user’s email account is compromised, all services using magic links are potentially at risk. This issue can be mitigated by encouraging users to protect their email accounts with strong security measures like two-factor authentication, and keeping the lifetime of a magic link low.

Here’s a brief outline of how you might implement magic links. Your API provider docs will have more specific instructions. 

  1. User Login Request: The user enters their email address.
  2. Token Generation: Your backend generates a unique token.
  3. Magic Link Email: The token is embedded into a URL and emailed to the user.
  4. User Clicks the Link: User authenticates by clicking the link.
  5. Token Validation: Your backend validates the token, logs in the user, and invalidates the token for further use.

While simple, this process must be coupled with solid cybersecurity practices, like HTTPS and secure token generation methods. It’s important to note that a magic link is not a password reset link. Password resets are for when users forget their password and need to be logged in again. A magic link is an authentication method that removes the need for users to know their password.

Closing Thoughts

Magic links provide a promising alternative to traditional password-based authentication, offering improved user experience and security. As developers, it’s our role to adapt to these changing paradigms to offer the best possible security solutions to our users. As we move towards a passwordless future, magic links are certainly worth considering. They’re easy to implement, they don’t require any special permissions, and they provide a seamless user experience.

Before switching over, ensure your team understands the benefits, risks, and implementation process. Remember, the goal is not just to follow trends but to enhance the overall security and usability of your systems. Embrace the magic of these links, and let’s stride towards a more secure digital future.