session - Secure cookies and mixed https/http site usage

Question

Lots of sites appear to support https but don't use secure cookies. I want to make my site use secure cookies but to allow for some content to be accessed using http instead.

A sensible way to do this appears to be to have a secure cookie for the real session, and a non-secure cookie which is just a flag to say if the user is logged in or not (to display different things in the header, like a logout link instead of a login link). This cookie wouldn't contain any "real" session information and is just so that the site can show pages slightly differently for logged-in users compared to logged-out ones on http portions of the site.

Having the whole site as https is another option but this appears to be quite a bit slower than plain http and so is not really ideal.

Why don't sites use this kind of set-up and have secure cookies? The possibility of cookie theft seems to make secure cookies a necessity nowadays. Is there a better way to achieve the same thing?

Answer 1

The solution you propose seems like it would work, as long as you don't mind non-authorized people being able to view the non-secure (http) part of the site 'as if they are logged in' - ie as long as the http part of the site does not contain any sensitive information, and the only difference between logged in and not-logged-in users is something harmless in the header.

The reason it is not used very often may be one of:

• This scenario may just not be very common. Usually if you care enough to make part of your site secure, you'd restrict the login session just to that secure part, or you'd make the entire site always use HTTPS (like Paypal).
• Pre-existing solutions exist which are secure and which are capable of more than this, for example logging in someone at an HTTPS login form and maintaining that session while transferring them back to HTTP. OpenID's an example. Also think flickr or gmail: their sign in page is always HTTPS, but once the session's started you migrate back to HTTP while maintaining the session securely.

---

Update (Aug 2014)

Since I wrote this back in 2009, the practice of having a secure connection for the login screen but dropping back to HTTP once logged in has all but disappeared.

The overhead of using HTTPS side-wide is not seen as much of a big deal anymore. The new SPDY protocol pioneered by Google (now evolved into HTTP/2) is supported cross-browser and by major web servers and improves HTTPS speed.

And lastly, privacy is seen as more important than ever, even for actions that aren't critical to the authentication, such as writing comments, uploading photos, and more.

Google has even said recently that sites which are HTTPS-only will start to benefit in search engine rankings.