WebApp Sec: Re: Is logoff feature necessary

["Adam Tuliper" <amt () gecko-software com>]

Possible, yes...doesn't seem very feasible though on a site with large # of 
logins, small # of secondary page hits. Traffic seems it would become a 
potential issue then, as well as current http connections to the server, and 
additional load on locking session information collections.... and.. its 
something that has to be built into every page and doesn't exist at the 
server level. Netbios broadcasts flood networks, as would a similiar "im 
still here im still here" messages. This would also require additional 
support on a client browser and assume they have permissions to allow such 
items.

----- Original Message ----- 
From: "Michael Silk" <michaelslists () gmail com>
To: <auri () auri net>
Cc: "Rod Divilbiss" <rod () rodsdot com>; <webappsec () securityfocus com>
Sent: Thursday, May 11, 2006 9:15 PM
Subject: Re: Is logoff feature necessary


On 5/11/06, Auri Rahimzadeh <auri () auri net> wrote:
> I agree. There is nothing that can guarantee a logout relying solely on 
> the
> browser.
Yes there is.

You can have your system require an "heartbeat" message every 10
seconds. This can come in the form of an fancy xmlhttprequest, if you
like, built into every page.

That way the browser is always connected, and if that message arrives
in 11 seconds instead of 10, bam, logged out. Of course you'd combine
this with maximum time logged in, etc, etc, etc. Logout is guaranteed
if the browser doesn't respond (i.e. crash). Logout isn't guaranteed
if someone forges your "i'm still here" message. But there are way
around that ...

-- Michael

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application security assessments should be considered a crucial phase in 
the development of any web application. What methodology should be 
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