ASP.NET 4 Unleashed

Cookie Security Restrictions

Cookies raise security concerns. When you create a persistent cookie, you are modifying a file on a visitor’s computer. There are people who sit around all day dreaming up evil things that they can do to your computer. To prevent cookies from doing horrible things to people’s computers, browsers enforce a number of security restrictions on cookies.

First, all cookies are domain-relative. If the Amazon website sets a cookie, the Barnes & Noble website cannot read the cookie. When a browser creates a cookie, the browser records the domain associated with the cookie and doesn’t send the cookie to another domain.

Note

An image contained in a web page might be served from another domain than the web page itself. Therefore, ...