Let's say a user is banned in a website, but his session is still active. What's the best way of preventing him from performing an action that a banned user is not allowed to do?
The two plausible solutions I came up with are
making an additional checking previous to every "major" action,
like making a post in the forum, sending a private message, etc. to make sure
he is not banned (checking with the database)
destroying his session
Now, the latter solution could be done by setting an expiration for the cookie, but this would be bothersome for the rest of the users as they would have to log in again.
Other option would be setting a timeout in the session in which the scripts checks if he's banned with the database and then destroying his session if he is, but this seems like a bit too much.
What's the best way to deal with this?
If I understand what you mean by setting an expiration for the setting cookie, I would recommend against it. You want the control to be on the server side - don't trust your clients; they can easily prevent a cookie on their side from being destroyed.
Hopefully, whatever framework you're using has a way to delete the server-side data associated with a user's session, instead, invalidating the client's session id.
If your application is object oriented, you could do a check in your constructor, if the user is banned, and if he is, unset his session/call the log out function.
Related
Passport by default allows the same user to login from multiple browsers and have unique sessions created. How can I configure it to destroy the first session when the user tries to create a second session?
Currently I'm using the 'Sessions' model to add the username to the record and upon subsequent login check by username if the sessions exists. But this increases traffic to the db. I'm thinking express must be doing it already or made to, keep the 'logged in users' information in memory so that the process can be simplified. I'd be thankful for ideas around how to achieve tweak with express for this purpose or any other workaround/suggestion.
Much thanks!
I saw that at least 4 users upvote this question, so I decided to create passport-strategy for that. The new strategy called passport-one-session-per-user. It's open source strategy you can access here: https://github.com/AminaG/passport-one-session-per-user
How to use it? add it right after session. For example:
app.use(passport.session())
var passportOneSessionPerUser=require('passport-one-session-per-user')
passport.use(new passportOneSessionPerUser())
app.use(passport.authenticate('passport-one-session-per-user'))
Not need for settings, or configuration.
How it is works?
The strategy, created an array that contain serializaed user objects, and sessionID.
Every time user logged in, the strategy check if the user already logged in. If so, it's flag the other session. The next time the user in the other session make a request, the strategy see the flag, and log the user out.
I'm thinking express must be doing it already or made to, keep the 'logged in users' information in memory so that the process can be simplified.
I believe the session model loggs the user in, and saves only that logged-in-ness in the session cookie. The server itself has no clue about who is logged in, but just checks this state in the (signed) session cookie provided by the browser.
You can write your own Passport.js strategy to handle it differently.
This is a follow-up question to Is Forms Authentication as described in the Nancy docs susceptible to session hijacking?
I understand now how Nancy Form Authentication works and also the idea behind it, thanks to Steven Robbins' answer.
However, for my application that approach is not sufficient. It must not be possible to gain eternal access for an attacker if he manages to steal the auth cookie once. Thus, I'm currently investigating possibilities to switch to a session-based approach to authentication, so I can invalidate sessions when the user logs out and also after a fixed amount of time.
Nice thing about Nancy, such things can be customized!
My question is, does it make sense to reuse Nancy.FormsAuthentication for that purpose? One solution I have in mind is making the user identifier only temporarily valid. That way I would delete the GUID identifier from the user database when the user logs out, and create a new one everytime a user logs in.
I'm asking because the docs state:
It is also important to know that the identifier should be treated as
permanent for the user that it was generated for and will be reused
across requests and application sessions.
Are there any unwanted side-effects when I ignore that and make the identifier non-permanent?
Yes and no.
If you change it each time the user logs in then you are effectively logging the user out.
You could create a Session / Identity table which allows the same user to login multiple times (assuming that the browser is different) which would allow you to manage the timeout / extending the timeout on each authentication.
That would require no changes to the Forms Auth, you would simply change the IUserMapper to authenticate against your Session / Identity table rather than the user directly.
(hope all that makes sense)
Is it a bad idea to put sensitive information (user ID's, connection strings, things I might not want visible to other user's) in the ViewBag? Can an external user get to that info in any way?
My thought is no, they can not get to it (I have tried, not that I am in LulzSec) but I was curious on other people's thoughts.
Thanks in Advance!
ViewBag is session based and it only the CURRENT request based and as such has the same constraints as the session with the added benefit that it is deleted at the end of that request, so no - this is not accessible. Even if someone could steal your session id and hijack the session, viewdata would be gone.
TempData is another story and session hijacking would allow a user to hijack another session - hence tempdata but a user still wouldnt be able to see that by default unless you have this information emitted into trace info. So basically if I could steal your session, whatever code you have on the next request would be executing for me, and not for the user its 'waiting' for on the next request. But - they still can't enumerate it and access it themselves.
Since the ViewBag is only used for server side processing, adding dynamic functionality to mimic a more Ruby- or Python-esque approach, I don't think you need to worry more about security than with everything else being stored and used on your server.
I have implemented custom membership provider in my project. i kept one flag on database to get the users online. i want to reset this flag on the log out, i can do this if the user log out properly . I have to reset the flag on database even if the the browser closed directly or on any machine failure or normal time out, any tricks on membership provider to solve this. experts am waiting for your answers!!!!!!!
Thanks.
just put a field for users like IS_LOGOUT_BUTTON_PRESSED typeof(bool) default false
if the user click LogOut set it TRUE.
if the user closes browser, it will stay false. Then you can see what user did.
I am afraid that you are tilting against windmills.
You will notice that the sql providers implement the 'users online' by simply updating last activity in most all provider methods (and subsequently the stored procedures) and then using a predefined 'online time window' to determine if the user may still be online.
To implement an authoritative 'is_online' flag would require that you have complete control over the user's means of starting a session and ending a session, which you do not and can not do due to both the nature of the browser ui and the way that sessions and ticket expirations are bumped.
So you can never really be sure whether a user is online or not, rendering any efforts you have made to track this metric unreliable.
And unreliable data is often of less value than no data at all.
I am quite certain that you will find nothing but frustration in attempting to apply an absolute, as described in your question, to the stateless and freeform nature of sessions and tickets.
Sorry I have not better news.
I'm trying to figure out exactly when the event Profile_MigrateAnonymous fires.
My best guess from just tracing through my code is that it fires when it detects BOTH an anonymous membership cookie AND an authenticated membership cookie. Can anyone confirm this? I'm looking for real in depth answer here. Not just it gets called 'when a user logs in'.
Now - why do I care?
I was trying to keep the anonymous profile hanging around after a user had authenticated so that once they log out I'd still be able to tell who they were, and certain settings that may have been set.
The problem I'm seeing is that Profile_MigrateAnonymous is getting fired on EVERY request. Not just when a user has logged in. This makes me believe it to be a bad practice to keep the anonymous cookie hanging around - and that I should always call ClearAnonymousIdentifier();
For instance I have a new store and an old store. I want users that have access to the 'new store' to never be put back on the old store. Obviously - as with most shopping carts you don't need to autenticate to begin a session. Therefore I think the only way is to call 'ClearAnonymousIdentifier' as designed but keep a secondary cookie 'UseNewStore' to track which store they should go to.
is this a good interpretation. Or should I just not care that Profile_MigrateAnonymous is being called all the time?
Don't bother with it. There is a simpler way
Migrating Profile Properties During Log On
http://msdn.microsoft.com/en-us/library/taab950e.aspx