Summary By combining two vulnerabilities (an Open Redirect and session token sent as URL query parameter) in Strapi framework is its possible of an unauthenticated attacker to bypass authentication mechanisms and retrieve the 3rd party tokens. The attack requires user interaction (one click). Impact Unauthenticated attackers can leverage two vulnerabilities to obtain an 3rd party token and the bypass authentication of Strapi apps. Technical details Vulnerability 1: Open Redirect Description Open redirection vulnerabilities arise when an application incorporates user-controllable data into the target of a redirection in an unsafe way. An attacker can construct a URL within the application that causes a redirection to an arbitrary external domain. In the specific context of Strapi, this vulnerability allows the SSO token to be stolen, allowing an attacker to authenticate himself within the application. Remediation If possible, applications should avoid incorporating user-controllable data into redirection targets. In many cases, this behavior can be avoided in two ways: Remove the redirection function from the application, and replace links to it with direct links to the relevant target URLs. Maintain a server-side list of all URLs that are permitted for redirection. Instead of passing the target URL as a parameter to the redirector, pass an index into this list. If it is considered unavoidable for the redirection function to receive user-controllable input and incorporate…Read More