Why WCF windows authentication? - wcf

Why use Windows authentication for WCF service hosted on IIS, if I can limit accessing the IP range to be "localhost", Is there a security hole here.
if not, then why Windows authentication is supported by WCF, sense I can restrict IPs for all Intranet scenarios.
thanks

If your IP range is stable (meaning very unfrequent changes on actual numbers) and you're comfortable with machines arbitrarly connected to your network having automatic access to your resources, then you may get away with your strategy. Most security officials though, will ask you to protect resources with user credentials, roles, and permissions.

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Securing an internal WCF service

I need to find out what's the best way of securing a WCF web service I'm writing. The service will be hosted internally and will perform checks against Active Directory and a third party database.
The service will be called by a public-facing webpage on a different server (a sign up page) and nothing else will be able to access it (due to firewall rules). The web page will NOT require credentials to access it.
The service will take a username and another field and check to see if they're an existing AD user. If they are, it will check to see if they have a personal (non-work) email address in the third-party database. If not, it will ask them to specify one.
Website <-> Service <-> AD/Database.
If these firewall rules are in place, do I need to go about securing the service?
These codeplex application scenarios might help you configure what you're trying to achieve:
Internet – Web to Remote WCF Using Transport Security (Trusted Subsystem)
Intranet – Web to Remote WCF Using Transport Security (Trusted Subsystem, HTTP)
This guide is well put together defiantly something to look into it covers all situations including yours.
http://wcfsecurityguide.codeplex.com/releases/view/15892

hosting wcf service on localhost iis

I am working on an Asp.Net application which will interact with WCF services that will be hosted on local machines on IIS.
In order to make these wcf services be hosted, what rights does user have to have when they log in? Do they have to have Admin rights on the machine?
P.S.: I know that WCF services should not be hosted on individual local machines so please do not start the discussion on that. All i want to know is what rights logged in user needs to have in order to make WCF services available to the application.
It really depends on how you set up the service. You can configure the website to allow anonymous access and set up your WCF binding to basicHttp binding with a security mode of None. That should allow any logged in user to run the site. This would NOT restrict users to only the one(s) logged in to the local machine, if that is what you are looking for.
You are dealing with two levels of security here. You will define your access in IIS to allow users to use the site. Then you will set up WCF service to allow the IIS site to access it. If you are using pass through authentication then you will need to authorize the individual users, perhaps with a local group?? Otherwise you need to authorize the identity that IIS is running the site under. So users do not need to be administrators, unless you specifically demand that role in IIS or WCF.

Active Directory authentication for SaaS product

After some theoretical help on the best approach for allowing a SaaS product to authenticate users against a tenant's internal Active Directory (or other LDAP) server.
The application is hosted, but a requirement exists that tenants can delegate authentication to their existing user management provider such as AD or OpenLDAP etc. Tools such as Microsoft Online's hosted exchange support corporate AD sync.
Assuming the client doesn't want to forward port 389 to their domain controller, what is the best approach for this?
After doing some research and talking to a few system admins who would be managing this, we've settled on an two options, which should satisfy most people. I'll describe them here for those who were also interested in the outcome.
Authentication Service installed in the origanisation's DMZ
If users wish to utilise authentication with an on-premises active directory server they will be required to install an agent in their DMZ and open port 443 to it. Our service will be configured to hit this service to perform authentication.
This service will sit in the DMZ and receive authentication requests from the SaaS application. The service will attempt to bind to active directory with these credentials and return a status to indicate success or failure.
In this instance the application's forms based authentication will not change, and the user will not be aware of the authentication behind the scenes.
OpenId
Similar to the first approach, a service will be installed in the client's DMZ, and port 443 will be opened. This will be an OpenId provider.
The SaaS application will be an OpenId consumer (already is for Facebook, Twitter, Google etc login).
When a user wishes to log in, the OpenId provider will be presented, asking them to enter their user name and password. This login screen would be served from the client's DMZ. The user would never enter their username or password into the SaaS application.
In this instance, the existing forms based authentication is replaced with the OpenId authentication from the service in the client's DNZ.
A third option that we're investigating is Active Directory Federated Services, but this is proprietary to Active Directory. The other two solutions support any LDAP based authentication across the internet.
Perhaps this might help…
This vendor, Stormpath, offers a service providing: user authentication, user account management, with hookups to your customers’ on-premise directories.
What about an LDAPS connection to the customer's user directory? They can firewall this off so that only your servers have access if they're concerned about it being public. Since it's SSL it's secure end to end. All you need from them is the certificate from their issuing CA (if it's not a public one). I struggled to get this working for an internal web project in the DMZ and there's a real lack of any guides online. So I wrote one up when I'd got it working:
http://pcloadletter.co.uk/2011/06/27/active-directory-authentication-using-ldaps/
Your best bet is to implement a SAML authentication for your SaaS application, and then sign up with identity providers like Okta or OneLogin. Once that's done then you can also connect it with ADFS to provide Single Sign On for your web application through Active Directory.
I'm just doing this research myself and this is what I've came across of, will have more updates once implementation is done. Hope this gives you enough keywords to do another google search
My understanding is that there are three possible solutions:
Installing something on the domain controller to capture all user changes (additions, deletions, password changes) and send updates to the remote server. Unfortunately there's no way for the website to know the initial user passwords - only new ones once they are changed.
Provide access for the web server to connect to your domain controller via LDAP/WIF/ADFS. This would probably mean opening incoming ports in the company's firewall to allow a specific IP.
Otherwise, bypass usernames/passwords and use email-based authentication instead. Users would just have to authenticate via email once every 3-6 months for each device.
I have to begin implementing this for an upcoming project and I'm seriously leaning towards option #3 for simplicity.

What restrictions does transport security with Windows authentication require?

I'm investigating using a WSHttpBinding in WCF with transport security and Windows authentication. However I'm having problems finding information on what restrictions using this applies to the server and client, i.e. domain membership of the machines or users and any restrictions that might apply in other areas.
If you use Windows Authentication then your service will authenticate against a single domain and it is fairly simple to setup. I believe you can setup a trust with other domains to allow them to windows authenticate as well but then you are opening up a door into a whole other level of complexity and/or security concerns.
Without knowning more about what the purpose of this service or how many domains (and how they are configured for access). I would probably consider using UserName Authentication which is also fairly simple to setup. This is a good link to get started on Custom Authentication.

What is the best suited authentication technique for this scenario?

Please suggest me the best authentication way to implement in the scenario mentioned below:
The requirement is I have to deploy a WCF web service in multiple countries across the world.
NOTE : All the machines on which the service is deployed are on the same domain.
1.The clients that access this service should fall in the same domain else the authentication should fail.
Currently I am using Message Security mode using "Windows"
I am curous why you would want the domain to be the same if it needs to be deployed in different countries around the world. Unless you are talking about hosting the service on an internal network that is not publicly exposed, enforcing the same domain name might be difficult. Different countries have different domain standards. America has a much richer set of domain roots to choose from. Other countries often have a country specific root, possibly with a regional subroot.
I would not couple your service to the domain that hosts it, nor would I recommend using the domain as a factor in authentication. If your service needs to be publicly exposed on the internet in each of these countries, I would recommend using something other than Windows security. A Claims-based security mechanism might work best. Internally inside the service implementation, claims can be checked, and if necessary, the windows identity can be authenticated separately from WCF authentication. Claims also allow you to utilize more than just a username/password or certificate to fully authenticate and authorize a client request. You can request the callers domain, country, region, and other evidence be included in the claim, allowing you to verify that calls are being made from the appropriate location and by the appropriate clients with much more flexibility than with Windows authentication (and if you publicly expose your service, Windows authentication will likely not be available anyway.)
Since you are running on an intranet and assuming that your Windows application will connect directly to the service, I would go with Transport Security using Windows authentication.
For some guidance consult patterns & practices Improving Web Services Security Guide.
I still question whether or not you need authorization. If you go with Windows authentication without any authorization it will simplify your service but will allow any domain user to access your service whether or not they are using the Windows application. Granted, they would have to have knowledge of the endpoint and the message structure but it would still be possible for them to do.
If Windows authentication is really all that is required, I would still raise the authorization issue and document it (and get sign off if applicable). On the one hand this covers you but also makes people explicitly aware of the decision and the possible risks.