While browsing the web, you’ve probably seen websites that allow you to log in using your social media account. In most cases, this feature is powered by the widely used OAuth 2.0 framework.

OAuth 2.0 is attractive to developers because it’s convenient—but it’s also very appealing to attackers. Why? Because it’s extremely common and often misconfigured. Small implementation mistakes can introduce serious security flaws, sometimes allowing attackers to access sensitive user data or even bypass authentication entirely.