I'm starting in .net and wcf services, sorry if what i'm asking is wrong or has nosense. By the way, sorry for my english too.
I'm trying to build several WCF services hosted on IIS where the internet clients can login with their username / password (info stored in db). When they are logged, they can access their info, see their private documents, change their profile and more actions related to their account.
Well, in asp.net if I get the session after success login, i can build services like "GetMyDocs" and i know "who is", just checking the session username stored with the session ID when he calls the login and his session don't timed-out. But i've noticed that WCF Services are stateless, so this seems i have to send in all requests the username / pwd and check them in the DB before executing the service... always!?
Later, if i want to build a client desktop / Android / iOS application, i will use those services. They then can manage their personal and private data through those apps after a success login.
How should i handle this?
Are WCF Services the way to go or WCF aren't a good choice for that?
How can i handle the user identification with WCF? Because all my services are linked to a user and "GetMyDocs", "SaveNewConfig", "PayItem"... needs to identify who is calling.
Thanks in advance!! Regards!
But i've noticed that WCF Services are stateless
This statement is kind of wrong. Because you could easily create a "WCF-based" web service with state enabled. Furthermore, state is such a broad term that is not worth covering here. For example, you could use session state with a WCF service, or you could set the InstanceContextMode property of a service to one of the following:
PerCall
PerSession
Single
and of course, it all depends on how you configure the service itself.
If your service needs to be consumed by different clients, you should consider at implementing a RESTful service along with OAuth 2.0 or something similar where you can authenticate a request using the Basic Authentication header or by issuing an access token after a successful authentication.
There are a number of ways to provide authentication to a WCF service. One of them is by using a session (basicHttp does not support session, you have to use wshttp, or any of several other transports that support session). However, enabling session is a huge amount of overhead simply to avoid sending credentials on each request.
Session reduces scalability by quite a bit, but if you aren't worried about it... it's an option.
Related
I am moving from ASMX web services across to WCF. With ASMX, for security purposes I passed a password as a parameter to my web methods. I'd like to introduce a better layer of security going forward. Theoretically an attacker could decompile my application that consumes the web service, extract the password and consume the web service maliciously. Can I make it in some way so that the web service can only be consumed by my client application and not by any other means including a decompiled version of its executable? Does WCF introduce any any superior security methods? I notice that the client object that consumes the web services has properties for credentials. What exactly are these properties and how are they implemented?
A good way to add security, when using WCF, is through message security (WCF also supports transport security but this has some quirks) which is configured in the binding on an endpoint, very straightforward. With this security you authenticate clients via a username or password or even a SQL membership store (with the correct configuration)
Check this example out:
http://dotnetmentors.com/wcf/wcf-message-level-security-by-example.aspx
Biggest benefits are quick bolting on of secure messaging and not having username and password parameters on your operations!
I have a client, which calls a service (passing it a user id and password). The first service can validate these credentials against users in a database. The first service then needs to call another service, but this second service cannot be passed the user id and password given to the first service (this is a requirement outside of my control).
The services will most likely be on different domains and both exposed to the internet (so security is a big issue here).
I am therefore looking at options for how the second service should check/validate that it is being called by my first service (and not by someone else trying to impersonate it).
One idea I've had is to add an additional service that acts as an authentication service, this could issue a token that is then passed to the second service which in turn calls the authentication service to check the token. Another idea (from a colleague) has been to assign an SSL certificate to each service, and check the certificate when the call comes into Server B - I haven't seen certificates used in this way though so am not sure if it's viable.
This is still at the design stage, so I am open to alternative ideas/approaches.
If you need an easy fix, then creating an extra set of credentials for service A so that service B can be sure it's called from an authorized party without knowing the clients credentials might be enough.
In the long run, something like Windows Identity Foundation sounds exactly like your plans with the authentication service.
So, both A and B parties are exposed to the internet (distrusted environment). Taking into account security requirements what you need is mutual WCF authentication. Certificates are the easiest way to achieve the goal - your server has to ensure that proper client calls it and the client has to be sure it calls proper server (DNS attacks, etc.). That means each party must have public key of the other to authenticate. Check this article for the details on how to configure your server and client.
I'm currently developing a web api, with WCF web api, which allows me to write restful apis. One concern I have is security. For this reason I decided to protect my api with the OAuth protocol which works very good. However, the team got to the conclusion that our own applications shouldn't be authorized by oauth, instead they sould be authorized by http basic, meaning that the client application should send username and password.
So I have 2 questions:
How can I set up WCF Web Api to work with SSL, I'm using Web Api preview 6, and the project is a MVC3 application?
I have an operation handler which takes care of the creation of IPrincipal from the client access token, and then injects it into the operation parameters, so I can access the user's info. I would like to have in the same operation handler a condition where I could check if the authorization scheme is OAuth or http basic, and then in the case of http basic extract the user's credentials and authenticate that specific user against my data base, if authentication is successful create an IPrincipal and inject it to the operation parameters. However, as I see it, everytime an application using http basic requests something to the api, I would have to go to the data base and authenticate. So my question is: Am I in the right path, or this could be accomplished in some other way?
Any answers would be appreciate it. Thank you in advanced!
You setup SSL for WCF Web API just like you would any other WCF service exposed over HTTPS. If you are hosted in IIS, then you need to configure a site binding for HTTPS. If you are self hosted, then the configuration is bit more involved. See http://msdn.microsoft.com/en-us/library/ms733768.aspx for all of the details.
To handle basic auth against a custom identity provider you would typically use a custom authz module when hosted in IIS. See [http://custombasicauth.codeplex.com/] for an example of how to do this. If you are self hosted then you can use a custom username passworld validator. See http://msdn.microsoft.com/en-us/library/aa702565.aspx for details.
Yes, I believe you are correct that every request will require authentication unless you establish some sort of session-like semantics.
Hope this helps.
Currently I am looking at securing our web services. At the moment we are not using WCF so this is not an option. One approach I have seen and implemented locally fairly easily was the approach described in article:
http://www.codeproject.com/KB/aspnet/wsFormsAuthentication.aspx
Which describes adding a HttpModule which prompts for user credentials if the user browses to any pages (web services) which are contained in a services folder. Does anyone see any way that this security could fall down and could be bypassed etc. I'm really just trying to decide whether this is a valid approach to take or not?
thanks
Seems a bit clumsy to have a person browse to a page in order to use a web service, which is typically done programmatically.
You can simply hide your web services behind formsauthentication, and have an authentication endpoint that sets the forms ticket.
The service client would then just hang on to the CookieContainer and use it for subsequent requests.
Whatever you do, you must ensure that any pipe that has credentials going through it is secured via SSL.
let's say we have a WCF service like the one from msdn examples -- c#, calculatorservice, with all the service settings on default.
if i were a hacker and i knew that calculatorservice was something important, that i want to make it stop working, i could simply hack the code for service references and make an application of my own that creates 10 clients. these clients would call a random (nonterminating) method on calculatorservice every now on then, to keep the session alive, and never close.
now obviously, since all 10 sessions are taken (or whatever the number of maximum sessions is), noone can access the calculatorservice, it is completely blocked!
how can we protect our services from that?
If you're afraid a malicious hacker will clog up your service with bogus sessions, then don't use sessions! Use the "per-call" approach, and authenticate your users, e.g. make sure they're either in your Windows/AD domain, or they do have knowledge of a username/password to make calls to your service.
Should a malicious hacker get a valid username/password combination for your service, then you cannot do much to stop him from constantly sending you 10 or 20 concurrent requests and clogging up your service - at least not at the WCF service level. WCF provides service throttling behaviors to prevent 1'000s of malicious concurrent calls in order to protect your server from being flooded and crashed.
If you need to keep away specific IP's or ranges of IP's, you'll have to approach that earlier on - in your routers/firewalls - the WCF service can't really help you there.
The best thing to do would be to secure your WCF service:
In this article I will show you how
you can implement security on a WCF
service. There are many options and
extensibility points for implementing
security in WCF. You can also use
specific products, such as the Windows
2003 Server Authorization Manager,
together with WCF to implement the
authorization requirements of a
solution. Out of the box, WCF supports
Windows credentials, Username Tokens
and X.509 Digital Certificates as
security credentials.