Web Application Security
concurrent logins Nov 19 2014 10:30AM
Robin Wood (robin digi ninja) (6 replies)
Re: concurrent logins Nov 19 2014 04:43PM
Seth Art (sethsec gmail com)
Re: concurrent logins Nov 19 2014 02:34PM
James Wright (jamfwright gmail com) (1 replies)
RE: concurrent logins Nov 19 2014 11:22PM
Zaakiy Siddiqui (zaakiy nticon com au)
Hi all,

I'm in favour of Arvind's Option Number 2: i.e., in my way of thinking it: Display to the user the Geolocation of other source IPs that have logged in with the same account.

Need to ensure though that if your users are using 3rd party services to login (common scenario is they use a feature-rich third party email provider which is hosted on the other side of the globe). May need to watch out of false positives there - scenario you want to avoid is that user would be confronted with a message saying that they've previously logged into this web app from the geolocation of an AWS datacentre.

There are plenty of services around e.g., MaxMind (I'm not linked to them but I use them) that charge something like USD$10 per 10,000 API-based geolocation lookups. This can easily be integrated into a web app or into a WAF. You can programmatically work out false positives like the one I mentioned above my not reporting AWS, Azure, Gmail IP ranges, which are publicly available - not perfect but a better balance IMHO.

Zaakiy (Zak) Siddiqui

-----Original Message-----
From: listbounce (at) securityfocus (dot) com [email concealed] [mailto:listbounce (at) securityfocus (dot) com [email concealed]] On Behalf Of James Wright
Sent: Thursday, November 20, 2014 1:34 AM
To: webappsec (at) securityfocus (dot) com [email concealed]
Subject: Re: concurrent logins

Hi Robin,

As you said, it depends a lot on what the application is for. If it is something like email, a user may wish to access it on a computer and a smartphone, and stay logged into both.

If the web based system requires more security, or is limited by a license (100 concurrent user limit) or another resource limit, it may be useful to limit concurrent logins. My thought on this is that the application should allow the logging on user to choose whether or not to disconnect the already existing connection. This way users can force off old and stale connections (reduced support from IT or AppDevs), and is alarming to the user if an attacker forces someone off (user will most likely report the occurrence).

With concurrent users, very few monitor or care about sessions other than the one they are currently using. Not allowing a user to login because of another running session is a headache for the user, and creates more support tickets.

Thanks,
James

On Wed, Nov 19, 2014 at 5:30 AM, Robin Wood <robin (at) digi (dot) ninj [email concealed]a> wrote:
> What are peoples opinions on allowing concurrent logins to web apps? I
> suppose it depends on what the app is used for - forum, admin suite
> etc - but do the protections from it add more problems that allowing
> it?
>
> Solutions I can see are:
>
> 1. Allow concurrent logins
> 2. Allow concurrent logins but report that someone else is logged it -
> like Gmail does 3. Don't allow them and kick out any logged in user
> when a new one logs in 4. Don't allow them and lock out all new logins
> till old ones have logged out 5. Give a warning popup when logging in
> to say the account is in use elsewhere as well 6. Allow but report
> back to an admin or log tracker or similar
>
> 1 is the default in most cases.
> 2 is a good idea but really, how many people look at the little thing
> in Gmail which says where else the account is logged in from, I don't
> and I'm sure normal users don't even know it exists.
> 3. Good but if an attacker gets creds or a reliable session hijack
> then they can use them to DoS legit users by keep logging them out.
> 4. Good but if an attacker gets in they can keep the account active
> and so DoS the real user by never letting them log in.
> 5. Maybe the best option but only works in the legit user logs in
> second otherwise the attacker gets the warning and ignores it.
> 6. Good one if people are watching the logs and can act on them.
>
> What other options are there? Can it be done in a good way that makes
> if of any use?
>
> Robin
>
>
>
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[ reply ]
Re: concurrent logins Nov 19 2014 02:33PM
Matt Konda (mkonda jemurai com)
Re: concurrent logins Nov 19 2014 02:32PM
Arvind (arvind doraiswamy gmail com)
Re: concurrent logins Nov 19 2014 02:13PM
DavidMeans833 (at) air-watch (dot) com [email concealed] (DavidMeans833 air-watch com)
Re: concurrent logins Nov 19 2014 01:17PM
Irene Abezgauz (irene abezgauz gmail com) (1 replies)
RE: concurrent logins Nov 21 2014 08:58AM
Nigel Ball (Nigel K Ball dsl pipex com) (1 replies)
AW: concurrent logins Nov 21 2014 10:20AM
Wolfgang Abbas (wolfgang abbas de)


 

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