OAuth is one of the fastest-adopted technologies in the Web, Android, and iOS application domain. OAuth (Open Authorization) is an open standard for access delegation that allows websites or applications to access user information without requiring passwords. This enables third-party services to exchange information on behalf of users, facilitating features like social media logins and secure data sharing between platforms. Users can specify which data to share, rather than giving third parties full control of their accounts. Major OAuth providers include Google, Facebook, Microsoft, Twitter, GitHub, and LinkedIn.

Md Rafi Ahamed is a cybersecurity researcher, bug bounty hunter, and penetration tester from Bangladesh. Today, he will discuss a web security vulnerability case related to an OAuth flaw. Such vulnerabilities have been found in many applications, including Facebook and Google OAuth. For ease of understanding, today's discussion will focus solely on the Facebook OAuth vulnerability.

In this article, he will not only recreate the discovery process of this vulnerability but also propose some protective measures to prevent such vulnerabilities. He believes that OAuth is a widely adopted and powerful technology for access authorization, enabling seamless and secure data sharing across different platforms. However, even robust systems like Facebook OAuth can lead to serious security vulnerabilities due to misconfigurations.

As developers, we must:

• Diligently verify access tokens to ensure the security of server-side and client-side calls;
• Regularly check the validity of tokens;
• Adhere to strict security measures, such as using HTTPS and enabling strict mode.

For more details, please click to read the article:OAuth Impersonation Attack: Misconfiguration of Facebook and Google OAuth Leading to Account Takeover Crisis