RE: Single terminal login

[<stevenr () mastek com>]

Hi
 
Updating the timestamp in the DB is a general workaround, but as I mentioned in my first post, if I update the DB for 
every page accessed, it will be a very expensive method for a high volume site.
 
Also, what Matt suggested about closing the prev session with every new login does make sense, but that would mean that 
a user would get in every time, invalidating the prev session. To give a background, I need to implement the Single 
Terminal Login concept to avoid password sharing among users, which is playing havoc with my audit trails. This method 
would work towards solving that, but the user will not realise that someone else is logged in from his/her account 
previously, possibly meaning a stolen password etc. 
 
Regards
Steve 
 

        -----Original Message----- 
        From: urbn () visi com [mailto:urbn () visi com] 
        Sent: Tue 2/17/2004 1:07 AM 
        To: Steven Rebello 
        Cc: webappsec () securityfocus com 
        Subject: Re: Single terminal login
        
        

         One factor you didn't mention is server resources issues, do you mind these
        
         sessions staying in memory for... hours?
        
         What I have done in the past is store user information in a database, and
         include a record that tracks the last time the database was accessed (each
         time
         a page is accessed or refreshed) a script is run to update this field.
        
         2 main fields, a filed that stores if they are logged in, and a field that
         stores a time (last time page access). 
        
         When the user tries to login, if this field is less then say 5 minutes old
         (preset time), they can not login.  After five minutes, if they are listed as
        
         Logged in, they receive a warning they did not log off correctly and must
        type
         in their password again.
        
         Don't really know if that was what you are looking for, because you run into
        
         issues with sessions being killed once the browser is closed, timeout issues
         on
         the server side, and many more issues.
        
        
        > Quoting Matt Wirges <wirges () purdue edu>:
        >
        > > stevenr () mastek com wrote:
        > > > Hi
        > > >
        > > > I have worked with web based applications since quite some time. One
        > issue
        > > to which I have not found a satisfactory answer yet is that of a problem
        > with
        > > Single Terminal Login in a web based application.
        > > >
        > > > By Single Terminal Login, I mean that if one user logs into a web
        > > application (say JSP based), s/he should not be able to login from
        > another
        > > machine or even another browser from the same machine. This can be
        > achieved
        > > easily by setting a "logged in" flag on the server side using a DB or
        > LDAP
        > > etc. When the user clicks on the Logout link, the flag is reset and only
        > then
        > > the user can login from another browser/window. Now the hitch. If the
        > user
        > > closes the browser directly, or the power goes out, or browser hangs and
        > has
        > > to be killed, the flag remains as "logged in". In short user cannot login
        > > into the system again. The one workaround used commonly, is setting a
        > timeout
        > > after which the user can login again, where a "last active time" is
        > > maintained for each user. Every login request is cross-checked against
        > this
        > > time and if the difference is greater than some threshold value, the user
        > is
        > > able to login again.  But this means that everytime the user does
        > something
        > > the "last active
        > > time" will have to be updated, which will be expensive in a high traffic
        > > site. Also, the threshold value is always a hot topic of debate :-)
        > > >
        > > > Does anyone know a better or a different approach to this? Would be
        > helpful
        > > if someone knows some site/papers for this. Have googled but havent come
        > > across any myself.
        > > >
        > > > - Steve
        > > >
        > > > "He who laughs last probably made a backup..."
        > > >
        > > >
        > > >
        > > > MASTEK
        > > > "Making a valuable difference"
        > > > Mastek in NASSCOM's 'India Top 20' Software Service Exporters List.
        > > > In the US, we're called MAJESCO
        > > >
        > > >
        > >
        >
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        > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        > > > Opinions expressed in this e-mail are those of the individual and not
        > that
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        > > Limited does not accept any responsibility or liability for it. This
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        > > or taking of any action in reliance upon this information by persons or
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        > > kindly delete this e-mail from all computers.
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        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        > > >
        > >
        > > Steve,
        > >
        > >    What we've done in the past on a few applications is simply close the
        > > old session the next time the user logs in.  For example, one of the
        > > applications I worked on is a web interface for incident response.  One
        > > of its features is time tracking to see how long a responder has worked
        > > on an incident.  So if the responder closes his web browser or his
        > > session expires, i.e. he doesn't log out via the application, the
        > > session remains active in the session table until the next time he logs
        > > in.  When the user logs in again, the system asks him to enter the time
        > > when he last used it and then closes the session updating it with his
        > > logout time and initiates the new session.
        > >
        > > In other applications I've simply just auto-closed the session when a
        > > new login is detected.
        > >
        > >
        > > -matt
        > >
        > > --
        > > Matthew Wirges
        > > IT Security and Policy Analyst
        > > Security and Policy
        > > Information Technology at Purdue
        > > wirges () purdue edu :: (765)49-62307
        > > www.itap.purdue.edu/security
        > >
        >
        >
        >
        
        
        



MASTEK
"Making a valuable difference"
Mastek in NASSCOM's 'India Top 20' Software Service Exporters List.
In the US, we're called MAJESCO

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