Re: IIS 5 cookie encryption password

[Santiago Barahona <sant-bar () dsv su se>]

Regarding the relationship between the cookie and the session ID:

 The cookie the web server generates and associates to a session ID  
is used to prevent DoS... basically what it does is that the server  
gives the cookies in the second face of the connection establishment  
and then "forgets" about it whilst it attends other connection  
requests which lines up in its stack... if the space in the stack is  
full, the server starts throwing away the oldest connection requests  
from the stack... if a client who's connection attempt has been  
dropped returns with the last phase of the connection establishment,  
it will still be able to connect because of the cookie...

Please correct me if I'm wrong...
cheers,

santiago


On 3 Apr 07, at 18:32, Serguey Forcade wrote:

Thanks, but I based my assumptions on an article from Microsoft
(http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/ 
iisbook/c06_asp_session_id_and_session_security.mspx?mfr=true)

Even tho your statement makes sense. It's just that I haven't been
able to find more info about the relationship between the session ID
and the cookie.

On 4/3/07, Rogan Dawes <discard () dawes za net> wrote:
> Serguey Forcade wrote:
> > Hi, I'd like to know if anyone knows of a paper that explains how to
> > extract the encryption password IIS creates when it starts up, and
> > uses to encrypt the session ID + random data in order to generate  
> the
> > cookie value the users receives.
> >
> > I'm interested in IIS 5.0.
> >
> > Thanks.
> >
>
> Take this with a pinch of salt, but I don't think that the session
> identifier and the cookie value are directly related.
>
> One reason for this statement is that if you abandon the session  
> (using
> ASP), and create a new one, the cookie value does not change. However,
> the result of "Session.SessionID" DOES change.
>
> I suspect that the cookie value is generated using a combination of  
> some
> static/sequential info, and some random data, and then associated with
> the next available (i.e sequential integer) SessionID. When the  
> session
> is abandoned, the session object associated with that integer  
> SessionID
> is discarded. A subsequent request from the client containing the old
> Session Cookie value will then automatically be associated with the  
> next
> available sequential integer SessionID.
>
> Hope this helps.
>
> Rogan
>
> P.S. One consequence of this inability to change the cookie value
> through abandoning the session is that ASP apps are AUTOMATICALLY
> vulnerable to Session Fixation
> <http://www.owasp.org/index.php/Session_Fixation>. An approach to
> protecting ASP apps against session fixation is shown here
> <http://www.owasp.org/index.php/Session_Fixation_Protection>

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