RE: Browser refresh sends username/password after log out -- URGENT

["Michael Silk" <michaels () phg com au>]

Well, I had a somewhat similar problem... my
app uses NT authentication, so I needed to find
the "AUTHORIZATION" header upon login to resolve
their name (for various things) and I found that
if I cleared the session (logout) and then went
"Back", the header was not sent again. so I simply
check for that (if my session is clear) and then
I know they are coming to my page from an invalid
zone... perhaps you can solve it similarly?



-----Original Message-----
From: K Kohli [mailto:krk41 () yahoo com]
Sent: Tuesday, 5 August 2003 2:56 PM
To: webappsec () securityfocus com
Subject: Browser refresh sends username/password after log out -- URGENT


I am into remote application testing for a critical
banking application. The following points will make
the question clear
1)We login and browse the banking site, do
transactions etc and then logout from there.
2)We get a page saying you have been successfully
logged out
3) Now we do a Back and refresh on the browser
window and we get a pop up "The page cannot be
refreshed without resending the information. Press
retry to sending it again ...." .
4) From here we say "Retry" and watch the data
going in a Web Proxy.
5) We are able to see the Username and password
again being sent to the server. When we compare
this request with the one sent from the first login
page( Where we give the username/password), both
are exactly the same. I feel thaat the same request
is being resend. This is a great security risk as
the credentials are being passed again.
6) Can anyone explain this behaviour and how to
avoid the resubmission of the credentials.
7) How many requests does the browser window store
in its temporary cache. 

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