Mastering Modern Web Penetration Testing

CORS

CORS allows cross-domain HTTP data exchange, which means a page running at origin A can send/receive data from a server at origin B. CORS is abundantly used in web applications where web fonts, CSS, documents, and so on are loaded from different origins, which may not be of the origin where the resources are actually stored. Most content delivery networks (CDNs) which provide resource-hosting functionality typically allow any website or origin to interact with themselves.

CORS works by adding a new HTTP header that allows the web server to speak up a list of whitelisted domains that are allowed to connect and interact with the server. This thing is also browser enforced; the browser reads the header and processes accordingly.

The following ...