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From Adam Hardy <>
Subject Re: Going from https on /, back to http on index.jsp?
Date Sat, 27 Sep 2003 10:50:54 GMT
An elegant solution by Amazon is to require a login everytime the user 
switches into SSL - even if they are logged in already.

Session hijacking still worries me though because the app I am building 
at the moment is quite data intensive, and the customers of the website 
who will use it to enter and store their data will obviously hold it in 
high value. It worries me that some discontented session-hijacker could 
easily destroy the data belonging to someone else.

The problem is that the average surfer would probably consider it weird 
that the whole site runs under SSL. Currently only sites such as PayPal 
do that. How much that could affect sales is something I will have to 


On 09/27/2003 03:38 AM Craig R. McClanahan wrote:
> Jayaraman Dorai wrote:
>>> -----Original Message-----
>>> From: Craig R. McClanahan []
>>> Sent: Thursday, September 25, 2003 10:55 PM
>>> To: Struts Users Mailing List
>>> Subject: Re: Going from https on /, back to http on index.jsp?
>>> Max Cooper wrote:
>>>> Creating an is one option. If it is not marked as     
>>> secure, sslext
>>>> will write an absolute URL back to http:// for it. Many Struts users
>>>> advocate that all requests should be served by Actions, even     
>>> if the action
>>>> merely forwards to a JSP.
>>> I actually have a more important concern about doing this -- exposing 
>>> information to people who can listen in on the packets that go back 
>>> and forth.
>>> Many people would like, for example, to have the login form be secure 
>>> so that your password is not sent across the wire encrypted, but then 
>>> go back to http for the rest of the session for the better 
>>> performance.  The seemingly ideal solution is to have the destination 
>>> of the login submit require SSL, and then switch back.  Using a 
>>> <user-transport-guarantee> security constraint, you can even let the 
>>> container worry about the http->https transition for you.  Or, you 
>>> can use things like SSLext that is nicely integrated into Struts.
>>> However, the servlet spec offers no help in switching back to http, 
>>> because it is not a recommended practice.  Why?  Consider the fact 
>>> that you now trust subsequent transactions from the same user, and 
>>> are typically using the session that was established earlier (whether 
>>> the session was originally created in http or https turns out not to 
>>> matter).  But the session id is no longer encrypted (it's either in a 
>>> cookie or in rewritten URLs), so it can be easily forged by anyone 
>>> with a network snooper between you and the server.  How do you 
>>> guarantee that an after-login request on that session is not being 
>>> sent by someone who is forging the session id because they snooped it?
>>> I'm a conservative on security issues -- if I have an app that needs 
>>> SSL sometimes, I arrange things to never accept a non-SSL request on 
>>> the same session again, once I've switched to SSL (easy to do with a 
>>> Filter, for example).  If you're concerned enough to protect the 
>>> password, you should be concerned enough to pay the CPU overhead for 
>>> SSL the remainder of the session.  Otherwise, it's likely that 
>>> encrypting the login form will just give you a false sense of security.
>>>> I think you can also use the secure attribute in the sslext     
>>> tags to indicate
>>>> whether the target of the link or form should be accessed     
>>> securely. In this
>>>> case, you would add secure="false" to the sslext:link tag     
>>> that goes back to
>>>> /index.jsp.
>>>> -Max
>>> Craig
>> Will it be useful for cases like where credit card information are 
>> sent through SSL and hence are secured. They might snoop the session, 
>> if it is switched back to http, but still the credit card information 
>> is not. Similarly, snooper might steal the sessionId, but the password 
>> is not stolen and is secured. Is that not better than nothing? Am I 
>> missing something?
> The credit card information is not going back and forth across the wire 
> unencrypted, but your session identifier is (for servlet based apps, 
> it's normally in a cookie or encoded into the URLs).
> In at least some ecommerce apps I'm familiar with, the credit card 
> number *is* stored in an HttpSession (or something analogous for 
> non-servlet technologies), so that the customer can go back and buy some 
> more stuff, and do an expedited checkout the second time.  If I know 
> that your app works that way, I can snoop the wire until the user goes 
> to https (which I can't read, but can see happening) and then back to 
> http (which I can see).  Now, I've got the cleartext version of the 
> session id, assume that the user has gone through the checkout, and can 
> submit false additional purchase transactions to your app based on that 
> session id, without having to resubmit a credit card number.
> Protecting just the password, but not the remainder of the current 
> session, is *not* better than nothing -- IMHO it is substantially worse 
> because it gives you a *false* sense of security.
> Craig

struts 1.1 + tomcat 4.1.27 + java 1.4.2
Linux 2.4.20 RH9

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