OAuth 2.0 is the industry-standard authorization protocol. It prioritizes client developer convenience while providing specific authorization flows for web applications, desktop applications, mobile phones, and living room devices. OAuth, which stands for Open Authorization Framework, is the industry-standard authorization delegation protocol. OAuth 2.0 is widely used by applications (such as SaaS platforms) to access data that is already available on the Internet. This includes, for example, your Google contacts list, your Facebook friend list, and so on. If you’ve ever been asked to grant access to your personal data by a web or mobile application, you’ve most likely used OAuth 2.0. Any OAuth 2.0 misconfiguration leads to an account takeover.
OAuth authentication vulnerabilities arise partly because the OAuth specification is relatively vague and flexible by design. In essence, OAuth provides developers an authorization mechanism to allow an application to access data or perform certain actions against your account from another application (the authorization server).
Generally, the account takeover via OAuth functionality occurs due to weak implementation of redirect_uri. The
redirect_uri is important because sensitive data, such as the code, is appended to this URL after authorization. If the
redirect_url can be redirected to an attacker-controlled server, this means the attacker can potentially take over a victim’s account by using the code themselves and gaining access to the victim’s data.
The way this is going to be exploited is going to vary by the authorization server. Some will only accept the exact same
redirect_uri path as specified in the client application, but some will accept anything in the same domain or subdirectory of the
redirect_url. Depending on the server’s logic, there are several techniques to bypass a
Whenever an OAuth authentication is being used, the first thought crossing the mind of an attacker is to check if the application validates the value of
redirect_url. This may lead to OAuth token stealing if the token is returned along with the callback request.
There are two different ways to perform this attack
Implement the following to mitigate or fix the vulnerability:
The blog addresses the essential issue with OAuth 2.0 misconfiguration: the general need for built-in security features. The security is almost entirely dependent on developers using the proper configuration settings and trying to implement additional safeguards, such as a robust authentication mechanism. It is important to note that vulnerabilities can arise on both the client application and the OAuth service. This article has helped you understand OAuth Vulnerabilities. There are plenty of other attacks and things that can go wrong in an OAuth implementation, but these are some of the more common ones you will see.
Securelayer7 is a leading penetration testing partner that offers state-of-the-art web apps, mobile apps, and cloud penetration testing to safeguard themselves effectively and their data from existing and emerging cyber tests. Contact us to find out how Securelayer7 can help with testing Oauth 2.0 misconfigurations.