Security of WCF endpoints - wcf

For the sake of argument, lets say that I've got a basicHttp WCF service. Besides implementing authentication (login/logout methods), what is stopping someone from just cracking open Visual Studio, adding a web reference to my website's service, and then playing playing around with my service? I'm not familiar with a method of stopping someone from doing this. The idea of someone downloading all of my Data/Operation contracts and then start playing around is keeping me up at night, and I like my sleep!

Discoverability is the driving factor behind Web Services and especially SOAs. The ability of anyone at all who can reach the service to pull up the WSDL, generate a proxy in Visual Studio (or some other tool), and start using the service is one of the main reasons to create a web service!
I suppose you could generate all the client proxies and then disable the mex endpoint, but that pretty much cripples WCF, and even then it's only security through obscurity.
If you don't want any miscreant to start hitting your web service then either don't use the basicHttpBinding (which is designed for the express purpose of immediate and anonymous consumption) or host the service on a private network which only trusted clients can reach.

Some form of authentication or encryption is the only thing that can prevent this. You have to distinguish between those you want give access to, and those you don't. Give the ones you want to have access the certificate necessary to do encryption, or the username and password.
Don't give anything to the others.

Related

Is a WCF service open for method calls for any computer in the network by default?

I have a silverlight web application and I am loading data to the client side using a wcf service. Should I secure the WCF service? Can anyone who's on the network call methods of the service?
Yeah they can see and access the service if they know the url.
And if they can see it, they only need to do a "Add Service reference" and they can see all methods available.
And since silverlight uses the basichttpbinding, it can work through firewalls (they typically allow http traffic).
You should secure it if it contains sensitive info.
By default you'll have security through obscurity, so if you're not broadcasting your WCF service's presence, it's not likely to be found or called. Additionally, it would be very hard to use it without having an appropriate client proxy configured. If you do not have the MEX endpoint set up, you are again pretty safe.
All that said though, you haven't really authorized the calls. It's theoretically possible to locate your WCF service and create a proxy to call it. So if you want to be safe, which I recommend, look into WCF authorization. It's fairly easy to set up, and you can use various options such as username-password, Windows accounts, or X.509 certificates. Each has its pros and cons.
This article goes into great detail, and there are others. http://msdn.microsoft.com/en-us/magazine/cc948343.aspx

How to conceal WCF service address in Silverlight?

We have silverlight application which consume WCF services. During penetration test we found few issues. One of the suggestion is to scramble / encrypt the WCF service address in silverlight side.
Is this a standard practice or does it have any value? Will the user be able to gain any information by knowing the WCF service location if the serivce is secured. Because the user can always decompile the silverlight xap and understand how we have encrypted WCF address.
Hiding secrets in data that you give out (e.g. in client-side code) is a notoriously difficult problem. Basically, this is what DRM systems try to do, and none of them are hacker-proof. If you give someone both the secret and the code that retrieves that secret, someone will figure the secret out. And as JeffN825 pointed out, you could always use wire monitoring tools to figure out the address (a bit more difficult with HTTPS addresses, but still possible). So, I would not put much effort into hiding the address, it's just security-by-obscurity that only delays a would-be attacker. If the service requires user authentication, I would just focus on making that part secure. If you're trying to authenticate the app, not the user, it's a much more difficult problem that requires a whole separate discussion, but it's not solved by address hiding.

Are WCF Web Service suitable for non-microsoft SOAP client?

I need to create a web service to collect data from my customer’s applications.
Those applications are programmed with different technologies and they all have one thing in common: they can consume plain SOAP Web Service.
I already have a WCF Service that could be exposed but as it was built for internal purpose only, I never had to secure it.
I did read a lot of articles on how to secure WCF service and how to consume it from a Microsoft client application. However, I'm really concern about the customer’s non-microsoft applications abilities to implement a standard WCF Service security. I must keep in mind that some of them might be stateless and unable to hold on to a session or anything that might be required by a secure WCF Service.
So here are the options I have right now.
1) Add username/password parameters to each WCF function and perform a credential check on every call. (I do have an SSL certificate... is it enough to consider this option as secured?)
2) Drop my WCF Service and create a plain SOAP Web Service with username/password parameters as mentioned in option #1 to be closer to my customer’s applications capabilities.
3) Implement standard WCF security and let the customers find a way to deal with it on their own. (The real question here: is WCF security simple enough to be implemented by any SOAP client?)
4) Change my name and move to Jamaica with my customer’s money before they find out that I’m a Web Service security noob.
5) Something else…
So what is the my best option here?
Yes, I can offer the option we use. It sounds like you want basicHttpBinding.
We have a WCF web service using basicHttpBinding and set IIS to use basic http authentication.
Therefore non-.NET clients can consume it easily (basicHttpBinding) and we can give them an Active Directory domain account that allows them access via IIS. No usernames / passwords to constantly send back and forth through the web service and it runs over HTTPS for security.
It's currently being consumed by PHP, Java and .NET clients. Yes, .NET clients can still import this as a service reference which makes thing like trapping FaultExceptions easier.
No solution is perfect for everyone but works great for our needs.
Yes, but certain configurations favour certain vendors. See the WCF Express Interop Bindings project on CodePlex:
http://wcf.codeplex.com/wikipage?title=WCF%20Express%20Interop%20Bindings
They offer settings for interop with:
Oracle WebLogic
Oracle Metro
IBM WebSphere
Apache Axis2
The Oracle Metro (previously known as SUN WSIT) stack is by far the most advanced as regards the WS-*/Oasis standards.

Securing a WCF service so that it can only be called by a Silverlight application

I am writing a Silverlight application that will be both reading and writing data to a serverside database via some WCF web services.
What is the best way to secure these web services?
My goal is to make sure the services can't be called by other applications and potentially spammed with requests to add items to the database. Only the Silverlight application needs to be able to access them.
Don is absolutely right that there's no foolproof way of making sure that the client is a Silverlight application.
However, I think you're asking more about the following: Can I make sure that only people I trust connect to the service.
The answer here is (basically) a yes, or at least we have standardized ways of doing this.
You're typically going to want to consider a couple of different approaches:
Transport level security. Has somebody tampered with the traffic? We use SSL for this.
Authentication. Am I talking to someone I trust? Here, we'll typically use one of the authentication mechanisms (Forms Auth, say). You can use Forms Authentication to secure both Silverlight (actually the page that Silverlight resides on) and the WCF services. Confusingly, SSL can be used (though rarely is because it's a pain in the neck) for authentication.
In general, you can't assume anything about the client. If you try to keep non-Silverlight apps from hitting your site, a malicious client can easily pretend to be a Silverlight app, and you're back to square one.
That is to say, this is not an effective way to secure a server. To secure your server, assume that any and all clients will hit your site, and start from there.
Edit:
Let me amend that to say that if you want to get into the world of mutual authentication, you can set up a PKI to manage certs, issue user certs for all your users, and then you know who your users are. Still, one of them might be malicious (and talented) and inject a cert into another client.

What are my binding options for a self hosted cross domain WCF service with remote thick clients?

I'm trying to build a WCF self hosted service (eventually in a windows service) that will receive binary and text base messages from remote thick clients that have no accounts on my hosted machine. I'm trying to figure out both my binding options and security options, and in reading the patterns and practices guides, my head has completely spun around at least once.
The clients would be authenticated against a custom SQL based method, so I'd like to be able to pass that info in the initial login request and then set an authorization token of some kind. (This part of the problem is probably outside the scope of the question, but I included it in case it might make a difference.)
Any thoughts at all would be very helpfull.
Ryan
The choice of binding and security option depends on the usage of your WCF service. Is it just for your rich client or are you planning to expose it to the world as API? If it's just for your rich app, does it run on LAN or over untrusted, unreliable Internet?
With WCF you can configure the service to expose multiple endpoints with different bindings, for example both SOAP and REST. In general, I'd start with something stateless and lightweight like basicHttpBinding and webHttpBinding, passing user and password on every request. Once you have that up and running you can optimize cache authentication, provide binary endpoint etc.. only if it actually helps.
There's no need to have just one binding. Having said that if it's self hosted you're "on your own" here. I've never looked at what's involved.