I've gotten a good number of OAuth logins working on my site now. My implementation is based on the WebSecurity classes with amends to the code to suit my needs (I pulled the WebSecurity source into mine).
However I'm now facing a new set of problems. In my application I have opted to make the user email address the login identifier of choice. It's naturally unique and suits this use case.
However, the OAuth "standards" strikes again.
Some providers will return your email address as "username" (Google) some will return the display name (Facebook). As it stands I see two options given my particular scenario:
Option 1
Pull even more framework source code into my solution until I can chase down where the OpenIdRelyingParty class is actually interacted with (via the DotNetOpenAuth.AspNet facade) and make addition information requests from the OpenID Providers.
Option 2
When a user first logs in using an OpenID provider I can display a kind of "complete registration" form that requests missing info based on the provider selected.*
Option 2 is the most immediate and probably the quickest to implement but also includes some code smells through having to do something different based on the provider selected.
Option 1 will take longer but will ultimately make things more future proof. I will need to perform richer interactions down the line so this also has an edge in that regard.
The more I get into the code it does seem that the WebSecurity class itself is actually very limiting as it hides lots of useful DotNetOpenAuth functionality in the name of making integration easier.
Andrew (the author of DNOA) has said that the Attribute Exchange stuff happens in the OpenIdRelyingParty class but I cannot see from the DotNetOpenAuth.AspNet source code where this class is used so I'm unsure of what source would need to be pulled into my code in order to enable the functionality I need.
Has anyone completely something similar?
AttributeExchange only applies to the OpenID Providers (Google and Yahoo!) and you can see the extension used in their respective source files.
I recommend against using email address as the username. Email addresses can be recycled (an account can expire or be closed/canceled and the email address can be reassigned to a new user). If this happens, your site based on email addresses would "give away" all the data of the old user to the new user. Massive privacy violation and lawsuit potentially happening there. Far better to use the Claimed Identifier for the OpenID cases, or the service provider-specific user id number in the OAuth cases, as the primary identifier in your user table. Certainly you may capture and display the email address everywhere on the web site where you would display a username so as far as the user knows that's the username -- it's just that internally you use something more precise than that.
Related
I'm working on a project that uses sessions to manage the currently logged in user with a slight twist, there is no log in form on the actual application. Instead, another site will provide a button that should log in the user and redirect to their profile page.
For example, the customer is viewing their profile on Site A, the 3rd party application. From their profile on Site A they click on a button that should log them in to Site B and redirect to their profile on Site B, the site I'm building.
I'm a unfamiliar with the security concerns for a case like this. My initial thought is that if Site A POSTs via https the user's email address and password, then it should work just as if they were filling the form out on my site, Site B.
What security concerns am I missing here or will this just not work at all?
NOTE: The 3rd party site is basically out of my hands and I'll never convince that team to setup any sort of OAuth protocol, or at the very least its going to take unacceptably long. Plus, OAuth, at least with my understanding is method to accept requests from any number of 3rd parties. No other site except for SiteA will ever attempt to log people in.
This sounds like a typical application for an OAuth provider.
Get an overview and grasp the concept here: http://en.wikipedia.org/wiki/Oauth
There already exists OAuth Providers in Ruby, so you don't have to do everything by yourself: e.g. https://github.com/songkick/oauth2-provider.
But if you really wanna do this without, then I would let the other server generate a hash containing the users id (can be username, email, or database id), a random token, the current timestamp and then sign this using MessageVerifier. Then you can check on your server if the timestamp is within a certain range (some minutes) and if the message verifies (using the same key naturally). If so, then accept the user.
If the other site uses PHP, then you might have to rebuild the generate method in PHP. Find the source in Ruby here.
Let's imagine I have following scenario
User receives an email that there is a new item waiting for her
Clicks on a link and is able to either confirm or reject item (details skipped)
Can then access a list of all her items
The trick is that I would like to allow all this happen without user signing in but then limit access to other parts of the website (like sending an item to another user)
How I see it is that:
when user clicks a link she is signed in but only on tier 1 - with access only to confirm/reject action and read only to index of items (that's when Devise session is created)
when user wants to access other part of the website the sign in page is presented
when user comes to the website just by typing in the url http://example.com and wants to access own account she is asked to sign in.
after sign in session is "promoted" to tier which allows full access
after some time of inactivity session is downgraded to tier 1 for security reasons
My inspiration comes from how Amazon works - you can access in read-only most parts of the account but before performing any destructible actions you need to sign in.
Does anyone have any experience with such approach or can share some blog posts, etc?
I didn's find anything on SO and Google mostly returned things about two-factor auth which is not the case here.
I also understand that there are security concerns with links in email.
I have implemented a very similar behavior few months ago. I don't have very interesting resources to show you but I can explain a bit how you could organize or think about the problem to solve.
Description
For the problem you state, it looks like once you have identified a user, you have two different states you can give him:
limited access (perform certain actions, read most of the resources, etc)
full access (allows them to do anything they would normally do).
Having stated that, what you need to do is figure out in which cases you will give a user each access state (for example):
signing in with email token -> limited access
password -> full access
authentication_token -> full access
omniauth -> full access
After that, you will need to save this information in the user session. This should be done anytime the user is authenticated, as you will know what strategy was used to authenticate the user.
To know if a user can or cannot perform an action you will need two things, know what the user can do, and the current "access state". Depending on those you will decide wether the user is allowed or not to perform a certain action.
Whenever a user can't perform an action and is logged in with limited access you should bring him to the flow for verifying his crendetials. This flow is pretty simple, almost like a sign in but just with the password. Once you verify his crendetials you can upgrade his authorization to a full access one.
Implementation details
I recommend you to create a Authorization model which will represent the "access states" that I mentioned. This model will have to be serialized in the session so you should be able to build it from a simple structure and serialize it again into that structure. The simplest the better (a boolean flag, an array or maybe a hash). For the case mentioned, it looks like a boolean would do the job.
Regarding implementation details, I recommend you implementing this with a Warden after_atuhentication callback.
You could implement this with CanCan by creating you own Ability that would be built with an Authorization instance and a User instance.
I think you're confusing authorization and authentication. Devise is an authentication solution, meaning it handles the "proof me you are who you say you are" part. Authorization is the "Ok, I know who you are, now let's see what can you do". Devise doesn't provide an authorization system beyond the simple "logged/not logged". If you need a more complex authorization system, use an authorization gem. CanCan is very popular.
There's a subset of users which will not have access to the system I'm implementing in the beginning but I need a mechanism for them to capture data for one specific part of the process.
An authorized user creates the original record for a Person with some basic details i.e. First name, last name etc.
I then create a 'DataRequest' record which has a unique guid and the external user is sent an email with a path which is effectively http://sampleapplication/Person/Complete?guid=xxxx
The external user adds additional details like Date of Birth, Eye colour etc, submits and saves to the DB. The DataRequest for that guid is then expired and cannot be accessed again.
The Complete action doesn't have any authorization as these external users do not have user accounts.
My preference is to force these users to use the system but at this stage I'm not sure it's practical.
Is this a bad practice?
Should I be implementing some additional security on this like a one time password / passcode contained in the email? Are there alternative approaches I should consider?
There's nothing wrong with opening up a section of your site to the public. Tons of websites have secured and unsecured sections. However, there's also nothing saying that you have to expose your secure site at all. You can create another site that merely has access to that change those records and make that site alone, public.
As far as securing the information of the user, passcodes by email are the invention of some developer somewhere with limited mental ability or a severe lack of sleep. If the link is only available by email (not discoverable by search engines and not easily guessable), then anyone with the link will also have the passcode, making the passcode to access the link redundant.
You should however log when the email is used to finish the record and then disallow further uses.
I need to semi-secure(meaning people could give these access codes away, and it will work for anyone) a site using access codes, no username or passwords, just a 5 digit access codes. But I would want to be able to still use the [Authorize] functionality. I believe I will I can't use the default membership (as its not really a membership), any ideas on how to approach this?
Use the standard SQL Membership providers.
Use your 5-digit access code as the username
Hardcode a default password in your controllers (so the user interface never sees it).
Caution should be used because this is very unsecure.
I'm currently implementing OpenID authentication for a website. During testing, I've noticed that Google accepts different versions of claimed Google Profile IDs, e.g.:
http://www.google.com/profiles/stefan.fussenegger
http://profiles.google.com/u/0/stefan.fussenegger/about
https://profiles.google.com/stefan.fussenegger
https://profiles.google.com/stefanfussenegger
Interestingly, the verified ID differs as well (for the samples above, same order):
http://www.google.com/profiles/stefan.fussenegger
https://profiles.google.com/stefanfussenegger
https://profiles.google.com/stefan.fussenegger
https://profiles.google.com/stefanfussenegger
Of course, this makes looking up the associated user account quite difficult, not to say impossible. Interestingly, all above IDs work for Stackoverflow. So I thought that there has to be some normalization step I'm missing in my implementation - or SO does some specialized voodoo to get things straight.
Looking at 7.2 Normatlization of the OpenID Authentication spec I found this:
URL Identifiers MUST then be further normalized by both following redirects when retrieving their content and finally applying the rules in Section 6 of [RFC3986] to the final destination URL. This final URL MUST be noted by the Relying Party as the Claimed Identifier and be used when requesting authentication.
Following redirects of claimed IDs doesn't help too much as I'm still left with two different IDs:
https://profiles.google.com/stefan.fussenegger
https://profiles.google.com/stefanfussenegger
Looking at redirects of verified IDs is much more helpful though as I always end up with this one:
https://profiles.google.com/stefan.fussenegger
Okay, looks like I should follow redirects of verified IDs, not claimed IDs.
The question now: Is it secure to follow redirects of claimed/verifed IDs, e.g. before search the DB like so:
do {
user = lookup(verifiedId)
if (user is null)
response = fetchUrl(verifiedId)
if (response.location is null) {
break # no redirect, jump out of loop, unknown user
} else {
verifiedId = response.location # use redirect location
}
} while (user is null)
return user;
If yes, I suspect that this should not only be done when looking up a user but when storing a new ID as well, right?
(If I should really follow redirect, I have another question about potential malicious redirects, but that will have to wait until I get an answer to this one. Might become obsolete anyway)
Open ID 2.0 says that during discovery,
URL Identifiers MUST then be further normalized by both following redirects when retrieving their content and finally applying the rules in Section 6 of [RFC3986] to the final destination URL. This final URL MUST be noted by the Relying Party as the Claimed Identifier and be used when requesting authentication.
So, according to this, you should take the user-supplied identifier and normalize it by following redirects & following normal URL normalization procedures.
The result is considered the 'claimed identifier' (CI). Next, you'll do the association dance and determine if this claim is true.
Note - Some providers have a 'well-known' OpenId Provider (OP) URL, for example Google. If you notice the sign-in process for StackOverflow, you can simply click the Google button instead of filling out a form. In this variant, the 'well-known' OP URL is not the users CI. The user did not provide you with a CI. You'll need to wait until you complete the authentication dance and Google tells you who the user is.
It's at this point (after receiving a successful association call-back from the OpenId Provider) that you'll have an identifier for the user. Per section 9.1 you SHALL receive either both an openid.claimed_id and openid.identity, or neither field if you're doing something fancy with extensions (I'm not very familiar with this aspect of the spec).
Now you should store the openid.claimed_id on your end - this will be the identifier unique to this user. This could be different from what the user originally supplied you. It might also be different from where you ended up (after following redirects on the user-supplied identifier). The OpenID Provider has the final say.
In regards to the security of following redirects on the user-supplied identifier. There shouldn't be an issue here. Redirects allow a user to delegate authentication to a provider of their choosing. No matter where the redirects lead you, you will end up asking that OpenId Provider to establish an association with you. When you make this request you'll supply the (normalized) claimed identifier and the provider can decide if they wish to be responsible for the claimed identifier, and they will (somehow in their infinite wisdom) authorize that the user has ownership of this claimed identifier.
Going back to Google, the claimed identifier Google will end up supplying you will look nothing like your examples above. The example they use is openid.claimed_id=https://www.google.com/accounts/o8/id/id=AItOawl27F2M92ry4jTdjiVx06tuFNA (source).
Hope that helps...
I'm using email as uniq identifier at this case. You can request it from google, see http://code.google.com/intl/en/apis/accounts/docs/OpenID.html#Parameters