OAuth 2.0 — OAuth (2024)

FAQs

Why is a bad idea to use OAuth 2.0 for authentication? ›

Perhaps the most infamous OAuth-based vulnerability is when the configuration of the OAuth service itself enables attackers to steal authorization codes or access tokens associated with other users' accounts. By stealing a valid code or token, the attacker may be able to access the victim's data.

OAuth 2.0 is a standard for implementing delegated authorization, and authorization is based on the access token required to access a resource. The access token can be issued for a given scope, which defines what the access token can do and what resources it can access.

OAuth 2.0 is not an authentication protocol.

This article is intended to help potential identity providers with the question of how to build an authentication and identity API using OAuth 2.0 as the base. Essentially, if you're saying "I have OAuth 2.0, and I need authentication and identity", then read on.

Opposed to OAuth, Basic Authentication is a more straightforward, yet less secure method embedded within the HTTP framework. It involves transmitting a username and password with every request, often encoded in Base64. This method, while simple, risks exposing user credentials more openly.

It states that OAuth 2.0 is deprecated.

OAuth 2.0 allows users to share specific data with an application while keeping their usernames, passwords, and other information private. For example, an application can use OAuth 2.0 to obtain permission from users to store files in their Google Drives. This OAuth 2.0 flow is called the implicit grant flow.

Principles of OAuth2.0

OAuth 2.0 is an authorization protocol and NOT an authentication protocol. As such, it is designed primarily as a means of granting access to a set of resources, for example, remote APIs or user data. OAuth 2.0 uses Access Tokens.

Authentication is ignored in OAuth2 and OIDC because it is a separate concern. This allows OAuth2 and OIDC to focus on the nitty gritty details of getting the resource owner to the authorization server as well as generating access and identity tokens.

Authorization Code Grant is the most widely used grant type to authorize the client. In this scenario, the authorization server will return a single-use authorization code to the client, which is then exchanged for an access token.

OAuth is an authentication protocol that allows two applications to communicate and share data without exposing the user's password. It uses a combination of security tokens and HTTP redirects to accomplish this.

How safe is OAuth? ›

OAuth is designed to work with Hypertext Transfer Protocol (HTTP). It uses access tokens to prove your identity and allow it to interact with another service on your behalf. In the event that this second service suffers a data breach, your credentials on the first service will remain safe.

When you compare both methods of authentication, OAuth 2.0 provides better security than basic authentication because its initial requests for credentials are made under the SSL protocol and its access object is a transitory token.

To authenticate using OAuth 2.0. Eloqua supports three possible flows that an application can use to obtain access on behalf of a resource owner: Authorization Code grant, Implicit grant, Resource Owner Password Credentials grant.

OAuth2 is not an authentication (login) protocol!

The purpose of OAuth2 Tokens is to authorize requests at a first party server (or API). If the third party uses the OAuth2 Access Token as proof of authentication, an attacker could easily impersonate a legitimate user.

It replaced OAuth 1.0 in 2012 and is now the de facto industry standard for online authorization. OAuth 2.0 provides consented access and restricts actions of what the client app can perform on resources on behalf of the user, without ever sharing the user's credentials.