Posts Tagged ‘IIS’Securing your WSDLMonday, October 4th, 2010This is a short follow-up to my previous post on Securing Web Services with Sitecore Authentication Providers in 5 easy steps. ASP.Net helpfully generates documentation pages for your web services automatically. This is the HTML that is served when you browse to an asmx file. It gives you a list of all the methods connected to the web service. Clicking into any one of these methods provides information on the parameters and return values, as well as the request methods that are allowed, generally SOAP and HTTP POST, but sometimes also HTTP GET. It also provides a link to the auto-generated WSDL file with a complete list of types, properties and method signatures provided by your web service. That’s great if you’re creating a web service designed to be consumed by the public, but a bit too much information to publish on your corporate internet site. At least that’s what I think. It’s more than enough information for a potential attacker to craft a well though out attack on your site and blind-side you. Frankly it’s the equivalent of hiding the key under the front door mat and leaving a note with directions to the key posted on the door. The Broadsword WayUsing the web.config file it’s possible to disable all documentation functions for all web services simultaneously. Noice. <configuration> This way you just get a “Request format is unrecognised” error. The Scalpel WayIt’s possible you don’t want to nuke everything. That’s OK. You can replace the standard auto-generated help pages without affecting the WSDL file by leaving the Documentation protocol alone and specifying a custom help page like so: <configuration> Note that the href is a file path and not a URL. Also you can use absolute or relative paths, but if you specify a relative path then it should be relative to the web.config file. You can also replace the WSDL file but that’s a bit harder. In your asmx class file, add one or more WebServiceBindingAttribute decorations to the class. This allows you to arbitrarily define multiple sets of metadata for use with your web service. So, for example, you could have a different WSDL file for each of several namespaces, or you could split the methods in the class across several namespaces. You can set the Name arbitrarily as it’s just an internal reference. Set the Location property to the URL of your WSDL file. This can be relative or absolute and if relative is in relation to the asmx file. On each method you can then specify a SoapDocumentationMethodAttribute passing in the name of a binding you set earlier. This tells the system which method should be emitted (and documented) against which binding. Noice. So by way of example straight from MSDN: using System.Web.Services; // Binding is defined in this XML Web service and uses the default namespace. // Binding is defined in this XML Web service, but it is not a part of the default namespace. [WebMethod] [WebMethod] Incidentally you can also use the SoapDocumentationMethodAttribute to specify element names in the request/response too. Noice.
Securing Web Services with Sitecore Authentication Providers in 5 easy stepsSaturday, October 2nd, 2010[Credits to http://keithelder.net/blog/] During a complicated project involving several 3rd party system systems I discovered that I had a need to expose some Sitecore functionality to external applications. The obvious model to go with was web services, since I could readily make use of the Sitecore context system to access and alter the environment. In the many articles that I read on the subject none seemed to address the matter of security. Not so much securing the web service from access by the outside world, but providing a properly authenticated Sitecore user for the Context object, rather than simply elevating privileges through the Sitecore.SecurityModel.SecurityDisabler class. In may particular case I had a Windows application that would call into the Sitecore web service (a simple asmx file within the website) using the .Net 3.5 service reference model. This required a number of fiddly configuration steps and I thought I would share these with the community. This is my first Sitecore article so please bear with me if I have made some beginner errors or assumptions – feedback via comments is always welcome! [ Let’s examine a plausible scenario. You have a page that allows users to sign up to your site. Posting the form calls a web service by AJAX to do the work of creating the user in Sitecore. If I look at your AJAX code I will be able to see the URL of the web service. From there I can query the web service’s WSDL file and discover all the methods you provide. Some of them will do interesting things. If I’m of malintent I could create 100,000,000,000 users in your system and attempt a denial-of-service. Or much worse depending on what other methods your web service exposes. You simply can’t rely on people not finding your file. They will. Google will. A colleague once described it as “security through obscurity” and it’s a fool’s defence. Incidentally you can prevent your web service from displaying the auto-generated WSDL (as you only need that for consumer web services once your site is live. See here for more information on protecting your WSDL. Step 1: Configure HTTPSSitecore authentication is performed with usernames and passwords being transmitted in the clear, a side-effect of Forms-based authentication. It is therefore imperative that you configure https to ensure the credentials cannot be trapped in transit. There are a million articles on configuring this for a production environment, but for a dev environment I’ll save you the trouble and describe them here.
You should now be able to access Sitecore using https, though you will likely get certificate errors from your browser because the certificate isn’t signed by a trusted authority. Don’t worry about that for now, in production you will use a properly signed certificate, won’t you! Step 2: Configure your Service ReferenceI’m going to assume you already have a Visual Studio project to house the code that will call your web service (the caller). I’m also going to assume you’ve already created your web service (the callee). Mine is called HelloWorld().
When you’ve done that you should see an app.config file appear in your project, or if you had one it now has some new content. If you are in a web project you will likely have guessed to look in the web.config instead. There is a <system.serviceModel> section in there. This specifies binding and endpoint information for your auto-generated service classes. There are a few things you will need to change – the important bits are below: <bindings> Step 3: Creating the Web Service extensionsIdeally the integration of the authentication doesn’t interfere with the business logic of our methods. We can use a series of attributes and supporting service extensions to help here. SitecoreAuthenticationHeader – a custom header that will transport our credentialsusing System.Web.Services.Protocols; public class SitecoreAuthenticationHeader : SoapHeader internal SitecoreAuthenticationHeader() { } public static bool Validate( SitecoreAuthenticationHeader soapHeader ) SitecoreAuthentication – a SoapExtension class that will detect the header and pass it on for validationNote that this raises an exception when validation fails since there is no elegant way to return values with a declarative syntax. using System.Web.Services.Protocols; public class SitecoreAuthentication : SoapExtension public override void ProcessMessage( SoapMessage message ) if ( !validated ) throw new AuthenticationException( “SOAP authentication failed. Credentials not specified.” ); SitecoreAuthenticationAttribute – a SoapExtensionAttribute that tells the infrastructure to include the SitecoreAuthentication extension into the processing stackusing System.Web.Services.Protocols; public class SitecoreAuthenticationAttribute : SoapExtensionAttribute public override int Priority Step 4: Integrating Sitecore Authentication DeclarativelyWe need to add a field to the WebService class. This will receive the header but importantly it will tell the framework that there is a header of a particular type that it needs to watch out for, which triggers the rest of the wiring. using System.ServiceModel; public class WebServiceAPI : System.Web.Services.WebService [WebMethod] If you were paying attention you would also have noticed the two additional attributes on the WebMethod itself. The SoapHeaderAttribute connects up the field and the header from the soap message, while the SitecoreAuthenticationAttribute provides the connection to the SitecoreAuthentication SoapExtension that will process the header and ultimately perform the validation. The FaultException is raised by the framework and contains the message from our AuthenticationException as a subset of some other messages. Step 5: Calling the web serviceHere is some sample code for actually making a call to the HelloWorld web service method. Note that I have already configured all the other stuff as described above. public class TestClass //create an instance of the service class //specify Sitecore credentials for executing the method //execute the method passing in the credentials Of note is the first line, that overrides the systems native server certificate validation with a lambda expression that simply always evaluates to true. This gets us around the fact our certificate is self-signed, but obviously don’t put that into production code (I use an app setting to disable it usually). Also of note here, the code generator has added the header as the first parameter to my method – it will do that. It ensures you don’t forget to supply the credentials. You can re-use the header object you’ve created by storing it somewhere convenient. I’d also be inclined not to hard-wire the credentials into the code, but that is up to your particular scenario. 1, 2, 3, 4, 5…DoneOnce you’ve got all that you will notice that you have a properly validated Sitecore.Context.User and you can use code, or add more extensions, to decide whether the user that is logged in has sufficient rights to perform the action.
Microsoft Exchange 2003 Direct Push and the Apple iPhone 3GWednesday, July 16th, 2008Like any good technophile I picked up a new iPhone 3G on Friday the 11th and the very first thing I did when getting back to the office was to try to get my Exchange Server to do Direct Push. I have had some small frustrations from the wide distribution of documentation on the subject so hopefully this post will save someone some time. For the sake of simplicity this article will deal with the simple case of:
Frankly if your setup is more complicated than that you probably already know how to do this and aren’t reading this anyway. Moving right along… This is what you’ll need before you get started:
Background Direct Push works because the internet is slow. That’s the headline. Basically the iPhone will make an HTTPS connection to your Exchange Server’s “Microsoft-Server-ActiveSync” virtual folder (most likely on the default web site). It will hold each connection open as long as possible, or until some pre-configured timeouts occur. Should you receive an email during this open connection, Exchange will send notification down to the iPhone which will tell you that you have new mail. Simple as that. The reason it works is because the internet protocols were designed to not receive an instant response from the server when making a request (see “slow” above). Direct Push takes advantage of this extended open connection. To prevent your battery from draining in 25 minutes flat the chatter on the connection is kept to a minimum. It’s very clever. Before You Start If you have a Wi-Fi connection active on the phone it won’t work. Direct Push only works over the air (the 3G connection). This is because the Wi-Fi radio will kill your battery. With Wi-Fi enabled I believe the phone reverts to a pull model, based on observation, but I can’t confirm that. Setup Is your iPhone’s Wi-Fi off? Step 1. Router/Firewall Setup
Step 2. Domain Name Setup
Step 3. Exchange 2003 SP2 Setup
Step 4. Configure Your Users
Step 5. Configure IIS
Step 6. Test Your Server Setup
Step 7. Setup your iPhone
That’s it – should be up and running now. Send yourself an email and see. Troubleshooting In my brief time setting this up here are the places where you might come unstuck:
Helpful Links Some of the pages that helped me: Microsoft – Enterprise firewall configuration for Exchange ActiveSync Direct Push Technology Exchange Team Blog – Direct Push is just a heartbeat away Brian M Posey (Exchange MVP) – Microsoft Exchange Direct Push Technology (seems to be broken) Apple’s less that complete instructions (don’t worry, it’s Apple, it just works! Right?)
Public proxied access to SharePoint (WSS or MOSS)Wednesday, April 30th, 2008We use Microsoft Office SharePoint 2007 internally to manage all kinds of work and share documents. It’s a very effective tool. We also use it to manage our software registration database. To facilitate customer software registrations we have a public-facing web service that uses SharePoint APIs to communicate with our registration site. The configuration of SharePoint required some fiddling to make this work. The problem was that we had SharePoint configured with no anonymous access, and obviously the users of our software that would be registering would not have credentials for our network – we didn’t really want to enable anonymous access so a creative solution was required. In order to achieve this we used the web.config <identity /> element in our public-facing website to set the identity of the thread to a fixed user account created just for the task. The web service application pool is configured in IIS to run as “Network Service”. The SharePoint API seemed to pick up the user from the HttpContext.Current.User object, rather than from the thread which means that all our communications were failing with 401.5 errors. I was a little surprised to discover that despite the <identity userName=“user” password=“pass” impersonate=“true” /> in the web.config file, the HttpContext.Current.User was still anonymous. The two tricks that made it work were:
The Global.asax trick ensures that the context carries the same user account as the impersonated thread. The AllowUnsafeUpdates is required when impersonating.
Flash FLV over IISWednesday, April 4th, 2007Recently I was deploying a web site with Flash video on. The Flash SWF files and associated FLV files (these are the ones containing the video that is streamed back to the user) were all in the correct directories however the videos still would not play. Instead I simply saw a blank screen. Windows IIS only serves files for which a MIME type is configured. There are several levels you can configure these including for the whole server (right-click server > Properties > MIME types) for a particular site (right-click site > Properties > HTTP Headers > MIME Types) or even for a folder beneath the site. You will notice that the settings are inherited, so specifying the value for the server negates the need to specify it for each site, and so on. Set the MIME type as follows: Extension: .flv MIME Type: video/x-flv (other MIME type settings may also work) If you altered the MIME setting on the server you will need to restart with “iis_reset” but if you only altered the setting for a given site then simply stopping and starting that site is enough.
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