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.
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So i'm tasked with implementing SSO for our Windows application. Currently, after a user logs into the machine, he or she has to re-log in to our app when he or she loads the application. The application validates the user by querying a LDAP server.
What we're looking to have is for the user to automatically be logged into the app when they click on it. My understanding is that the LDAP authentication must still happen, but Im not exactly sure what the workflow would be, and how exactly we can validate a user without requiring them to re-enter a username / password. Note that this is not a web application so I can't use tools like SAML or OAuth (unless i'm mistaken about this too..?)
So my specific question is as follows:
Is it possible to use LDAP for SSO, and if so, how? Is it possible for me to authenticate a user with just his or her username, or is a password also required?
Any guidance would be appreciated, and am happy to provide further clarification if needed.
First of all, LDAP is a protocol, which you use to communicate with databases that implement this protocol.
So LDAP databases (commonly called directories) are ... databases and so do not provide SSO functionality.
To deploy a SSO solution, you need a SSO service. All your applications will have to be "compliant" with this service in a way or another.
The only way I can think of to make a "Windows SSO" without adding a third party application is that the applications can retrieve NTLM informations in requests made by the client and uses the user data to identify him. (but in term of security, I let you judge what you think about it ;) ) . See this php example
Some LDAP implementations, including OpenLDAP, provide some level of support the Generic Security Service Application Program Interface (GSSAPI) or SPNEGO (a specific GSSAPI implementation)
Although not trivial, it is possible to perform SSO from a "browser" that supports GSSAPI. AFIK, IE, Firefox, Safari and Chrome all provide some level of support for GSSAPI although each browser requires specific configuration (typically whitelisting of Servers).
There are many SSO Products that implement these features in a "probably" more secure and easier process than doing it yourself.
There are many known vulnerabilities details that have been exploited with GSAPPI/SPNEGO typically due to implementation issues.
There is a lot of discussion about microservice architecture. What I am missing - or maybe what I did not yet understand is, how to solve the issue of security and user authentication?
For example: I develop a microservice which provides a Rest Service interface to a workflow engine. The engine is based on JEE and runs on application servers like GlassFish or Wildfly.
One of the core concepts of the workflow engine is, that each call is user centric. This means depending of the role and access level of the current user, the workflow engine produces individual results (e.g. a user-centric tasklist or processing an open task which depends on the users role in the process).
In my eyes, thus a service is not accessible from everywhere. For example if someone plans to implement a modern Ajax based JavaScript application which should use the workflow microservice there are two problems:
1) to avoid the cross-scripting problem from JavaScript/Ajax the JavaScript Web application needs to be deployed under the same domain as the microservice runs
2) if the microservice forces a user authentication (which is the case in my scenario) the application need to provide a transparent authentication mechanism.
The situation becomes more complex if the client need to access more than one user-centric microservices forcing user authentication.
I always end up with an architecture where all services and the client application running on the same application server under the same domain.
How can these problems be solved? What is the best practice for such an architecture?
Short answer: check OAUTH, and manage caches of credentials in each microservice that needs to access other microservices. By "manage" I mean, be careful with security. Specially, mind who can access those credentials and let the network topology be your friend. Create a DMZ layer and other internal layers reflecting the dependency graph of your microservices.
Long answer, keep reading. Your question is a good one because there is no simple silver bullet to do what you need although your problem is quite recurrent.
As with everything related with microservices that I saw so far, nothing is really new. Whenever you need to have a distributed system doing things on behalf of a certain user, you need distributed credentials to enable such solution. This is true since mainframe times. There is no way to violate that.
Auto SSH is, in a sense, such a thing. Perhaps it may sound like a glorified way to describe something simple, but in the end, it enables processes in one machine to use services in another machine.
In the Grid world, the Globus Toolkit, for instance, bases its distributed security using the following:
X.509 certificates;
MyProxy - manages a repository of credentials and helps you define a chain of certificate authorities up to finding the root one, which should be trusted by default;
An extension of OpenSSH, which is the de facto standard SSH implementation for Linux distributions.
OAUTH is perhaps what you need. It is a way provide authorization with extra restrictions. For instance, imagine that a certain user has read and write permission on a certain service. When you issue an OAUTH authorization you do not necessarily give full user powers to the third party. You may only give read access.
CORS, mentioned in another answer, is useful when the end client (typically a web browser) needs single-sign-on across web sites. But it seems that your problem is closer to a cluster in which you have many microservices that are managed by you. Nevertheless, you can take advantage of solutions developed by the Grid field to ensure security in a cluster distributed across sites (for high availability reasons, for instance).
Complete security is something unattainable. So all this is of no use if credentials are valid forever or if you do not take enough care to keep them secret to whatever received them. For such purpose, I would recommend partitioning your network using layers. Each layer with a different degree of secrecy and exposure to the outside world.
If you do not want the burden to have the required infrastructure to allow for OAUTH, you can either use basic HTTP or create your own tokens.
When using basic HTTP authentication, the client needs to send credentials on each request, therefore eliminating the need to keep session state on the server side for the purpose of authorization.
If you want to create your own mechanism, then change your login requests such that a token is returned as the response to a successful login. Subsequent requests having the same token will act as the basic HTTP authentication with the advantage that this takes place at the application level (in contrast with the framework or app server level in basic HTTP authentication).
Your question is about two independent issues.
Making your service accessible from another origin is easily solved by implementing CORS. For non-browser clients, cross-origin is not an issue at all.
The second problem about service authentication is typically solved using token based authentication.
Any caller of one of your microservices would get an access token from the authorization server or STS for that specific service.
Your client authenticates with the authorization server or STS either through an established session (cookies) or by sending a valid token along with the request.
I am working on a security component to use with an ESB for a client with very concrete high level requirements:
Integrate into an existing IWay service manager version 5.5 ESB (there is no security system in the existing set up).
Provide authentication and authorisation level information from source data stored in an existing active directory server used for another system (preferably using LDAP).
Authentication and authorisation should be performed in the ESB as the interface for the ESB will be exposed to both internal and external clients so total control over the client is not possible.
The client can not be relied up to have a certificate to allow bilateral SSL authentication, however unilateral authentication, where the client checks to see he is hitting the correct server is possible, so HTTPS connections can be established.
The service should sit on Weblogic (but I will be happy to take suggestions regardless)
Further information:
IWay ESB is a commercial, closed and fairly poor solution, in version 5.5 it provides no out of the box solution which fits the requirements. it is also stateless so no sessions can be maintained other than using a cookie or some method similar to store information.
Current ideas:
To implement a SSO service that is added to the messaging bus which provides a identity provider, service provider functionality, so an initial authentication will provide a token, which can then be stored by the client and passed with each subsequent request to be authenticated and an authorisation level passed (which i believe to be a fairly standard design pattern).
Research has been carried out on SSO + SAML implementation, openAM, Shibboleth, CAS all seem to provide a too complete solution which caters more for a portal type architecture (like CAS) or from a system where the initial SAML identity token is received from another sever altogether and then brought to the system (like googles implementation of SAML for some of its services).
I have also looked into JBossESB, openESB and service mix solutions which seem to use a bespoke implementation of SAML which can't be ported onto Weblogic and Zxid which has limited documentation.
It is a complex undertaking so I am expecting more high level architectural styles and library/project suggestions rather than complete solutions. I am under the impression that this should be a reasonably common requirement, a authentication and authorisation service for a ESB which uses a token system to prevent credentials having to be continually entered or stored in plain text but I am unable to find much information, what am I missing?
Any further questions I would be more than happy to elaborate.
It seems a solution using SAML is a valid solution for when users potentially/do require to access a third party service on an ESB but don't want the third party service to be aware of the security specifics of the ESB and the credentials information of the user. This way the ESB may provide a SAML token provider where the user can get the ticket and transport it to different services for authentication, the services then check back with the token for authentication and possible authorisation information (with SAML2 only). In addition to this SAML could be used like open ID where users are managed externally and users go to the external token provider to get SAML tickets.
This was a valid solution for us as the the client wanted to be very aware of the users accessing the ESB and there was to be no plan to access third party services as it was a completely closed system.
We subsequently implemented a more custom SAAS (security as a service) mechanism for internal authentication and authorisation inside the ESB (I know it sounds bad but with iWay there are limited options) using spring security libraries and the remember me functionality which in our case met the requirements.
Low and behold our clients then changed their requirements and asked for integration with share point. This did however simplify the security model in our system because we then designed of the following:
iWay's primary security model is based around SSL certificates, it is possible to implement an SSL Provider which will manage certificates, you should therefore be able to supply share point with your SSL certificate and iWay with the public certificate and secure up the channels between the 2 servers, you can then manage users within iWay who can access the ESB on a system level and specify a share point user even specifying it's ip, this information is sent in plain text but over SSL and in our case sent between servers in the same network.
We are then leaving it to share point to authenticate users on a finer level so access to applications is managed at the share point 'portal' level and the only thing the ESB is vaguely aware of is the authorisation information which is passed with the client SOAP message and defines to what level the services can be accessed (this information is used on a service level).
Downsides to this solution are:
For each new client application developed to access the ESB interfaces a new ESB user must be configured so it is not possible for clients to be developed which can freely consume certain services on the ESB.
New clients have to implement the authorisation logic so the correctly formated authorisation string can be sent and understood by services.
Other points:
I am aware that the newer version of iWay provides a LDAP adaptor which should be able to communicate with AD so you can have your LDAP server attached to the ESB through this way so it could possibly be consumed by another client or services in the ESB but you would have to customise share point to access the information through the iWay business provider.
I also believe iWay 6 provides a SAML token provider which you could utilize (going back to what I said previous about the use of SAML) but I don't believe this fits in with a share point solution.
I would like to share more ideas seen as we are both doing the same thing, can you find me through my twitter account which is specified in my blog?
We are currently working with iWay Server Manager 6.0.1 and are also having difficulties identifying HOW to handle security for web services within this tool.
We want to build web services with it that have AD security in them like if we were using .NET Web Services and haven't found a solution. Even discussing this with the iWay staff did not clear it in our minds.
Now we have to connect to SharePoint web services and the issue will definitely be there.
Have you progressed with your situation? We would like some feedback from people using the tool on how they actually implement security with iWay.
Sorry for the delay... been quite busy over here...
Basically we've done many tests between iWay and SharePoint and we are not able to set it up to sent the NTLM credentials required by SharePoint. We've tried setting up channels, proxies and various other solutions within the tool...
We've placed a call to them to hopefully get some help...
Pascal
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.
We are developing an app that consists of a web server that hosts a web service (amongst other things) and a client that will be communicating with that web service. Both the client app and the server are expected to be used within a corporate firewall. This application will be packaged up and deployed to organizations across the world—so it needs to be flexible enough to work in multiple types of environments.
My question revolves around web service authentication and what is appropriate for real world scenarios. I know some companies have proxy servers that require a separate authentication. How often is this a requirement across organizations? When does the proxy server force the user to authenticate (can you access internal sites without authenticating.. is the authentication for only external sites)?
Reason I ask these questions, is I’m not sure what kind of capability we should build into our client application for authentication to the web service. By default, we are taking the current user credentials and passing that up to the server. Do you think this is sufficient? In a case where a company will require some form of alternate authentication for internal access, this will not work. My question revolves around this last case—how often does it happen? Why would a company force alternate credentials for internal access?
Thanks!
Why not make it configurable? Further, use WCF and you have the ability to configure just about anything you might need, in most cases without changing your code.
If Internet Explorer can reach a site through the proxy server without prompting the user, your call to the web service should "just work". If the user is prompted by IE, you'll need to put together a way to fill in the proxy server authentication information.
I've run into quite a few problems getting web services rock solid, but never had a proxy server authentication issue.