I study microsoft explanation about Service Credentials Negotiation.. but i don't understand What is Service Credentials Negotiation and when we should use it?
Negotiation is the process of establishing trust between a client and
a service by exchanging credentials. The process is performed
iteratively between the client and the service, so as to disclose only
the information necessary for the next step in the negotiation
process. In practice, the end result is the delivery of a service's
credential to the client to be used in subsequent operations. With one
exception, by default the system-provided bindings in WCF negotiate
the service credential automatically when using message-level
security. (The exception is the BasicHttpBinding, which does not
enable security by default.) To disable this behavior, see the
NegotiateServiceCredential and NegotiateServiceCredential properties.
http://msdn.microsoft.com/en-us/library/ms733836(v=vs.110).aspx
So, by default the system-provided bindings in WCF negotiate the service credential automatically when using message-level security with exception of BasicHttpBinding and you only need to worry about it if you need to change this default behavior and provision credentials at the client instead of letting the service take care of that for you through process called negotiation...
Related
I would like to know the difference between TransportWithMessageCredential Vs Message in terms of WCF security.
What I know is:
Transport security: Is used to provide point-to-point security between the two endpoints.
Message security: It provides end-to-end security. Because message security directly encrypts and signs the message, having intermediaries does not break the security.
If we use TransportWithMessageCredential mode, is the SOAP message (Header and Body) encrypted?
My concern is that I want to have the application data to be encrypted between WCF server and my WinForms client.
If we use TransportWithMessageCredentials mode , Is SOAP message(
Header and Body) encrypted?
Yes, since with TransportWithMessageCredential security mode it is transport security which is providing confidentiality and integrity protection for the messages that are transmitted over the wire. Transport security also provides service authentication in this case. For example, with HTTP, Secure Sockets Layer (SSL) is used for encrypting and signing the contents of the packets sent over Secure HTTP (HTTPS).
With TransportWithMessageCredential security mode, client authentication is provided by means of SOAP message security where the client credential is put directly in the message.
When the SOAP message leaves the client for the service it is encrypted. However, as with transport security it provides point-to-point (not end-to-end) security between the two endpoints (service and client). So if there are intermediary systems between the client and the service, each intermediate point must forward the message over a new secure connection.
Update Per Comments
you said "When the SOAP message leaves the client for the service it
is encrypted' Then it should be end -end security. why it is only
point -to-point.
Transport security is point-to-point because a message is encrypted when it leaves one endpoint and remains so until it reaches the other endpoint of the secure transport where the message is then decrypted. In deployments where the client and server are talking directly to each other, then this provides encryption the whole way through. However, if your service endpoint is going to forward that message onto the intended recipient, then your message is no longer guaranteed to be encrypted from that point onward.
Message security directly encrypts and signs the message so that only the intended recipient can decrypt and read the actual contents of the message. Therefore security is guaranteed between sender and recipient and not just between endpoints. Therefore, message security provides end-to-end security.
Can i conclude TransportWithMessageCredential provide security point
-to-point and message Level security provide End-to-End Security. then Why WCF security Guide is suggesting to use
TransportWithMessageCredential with UserName When we are using WCF
with Windows form client in internet.
Yes, that is correct. TransportWithMessageCredential security provides point-to-point and Message security provides end-to-end security. The WCF Security Guide is suggesting to set the client credential to UserName because this will be used to authenticate the client. In the UserName case, we have the username and password pair being put directly in the SOAP message. Unless the client provides some sort of credential such as a UserName or Certificate to authenticate themselves to the service you will have an anonymous client. An anonymous client means that anyone can access your service since the client is not being authenticated.
If message body is not encrypted with TransportWithMessageCredential
then why Microsoft says TransportWithMessageCredential is a
combination of both Transport and Message security
As with my original answer: The SOAP messages are encrypted and signed by the transport layer (e.g. HTTPS). TransportWithMessageCredential is a combination of both transport and message security since transport security encrypts and signs the messages as well as authenticates the service to the client and message security is used to authenticate the client to the service.
i want to encrypt messages in a WCF scenario where the binding is tcp.NetBinding and the security is bound on transport.
I found out, that if i dont encrypt the messages, i dont have to make client credentialhandling between client and server.
But if i want to encryt, it seems that there has to be some kind of
client-authentication (Windows credentials, Certificate ...).
The WCF server wont start with credentials are set to Null and encryption is on.
Is it possible to encrypt messages between the client and the server without authenticating the client?
Thanks a lot
Yes, the scenario is called Transport Security with an Anonymous Client:
This Windows Communication Foundation (WCF) scenario uses transport
security (HTTPS) to ensure confidentiality and integrity. The server
must be authenticated with a Secure Sockets Layer (SSL) certificate,
and the clients must trust the server's certificate. The client is not
authenticated by any mechanism and is, therefore, anonymous.
The bare bones binding is setup as follows:
var binding = new NetTcpBinding();
binding.Security.Mode = SecurityMode.Transport;
binding.Security.Transport.ClientCredentialType = TcpClientCredentialType.None;
Also in this particular scenario, the security is provided by TLS over TCP to ensure confidentiality and integrity. Again all that is required is to have the client trust the certificate provided by the server. The client is not authenticated by the server and is therefore known as an anonymous client.
What's the easiest security mode for implementation in WCF when:
Both client and service are .NET applications.
Client and service are negotiating over internet.
SSL in not available.
Port 80 (web) is preferred for communication.
And Using a x 509 certificate should be the last option (same credentials in configuration file at both sides is preferred, if possible)
Security means a lot of things:
Authentication
Authorization
Confidentiality
Integrity
To name a few. You need to decide what are your requirements for each.
Since SSL is not available you must use message level security. But assuming machines do not necessarily live on the same windows domain you cannot use windows authentication and must use x.509 certificate, at least on the serve side. So:
<customBinding authenticationMode="usernameForCertificate" />
where the client authenticates with a username and the server with a certificate (client need to install this certificate).
You could also use a WSHttpBinding with all default settings except:
messageClientCredentialType=UserName
In which case client does not need to install the certificate, it gets it automatically in runtime via negotiation.
Both client and service are .NET applications.
Take a look here http://msdn.microsoft.com/en-us/library/ee707353(v=vs.91).aspx
I'm looking into WCF & Security.
There are several security modes but the big picture is that there are 2 main "layers" you can secure : Transport or Message.
Can someone explain this in more depth please?
What do I have to imagine when I'm securing Transport, how does it work, etc.
it is pretty much as you'd expect, transport security secures the transport - e.g. SSL over HTTP, whereas message security secures messages. Here's an msdn overview for reasons to use message security:
http://msdn.microsoft.com/en-us/library/ms733137.aspx
and an overview for transport:
http://msdn.microsoft.com/en-us/library/ms729700.aspx
(From the message security link):
Windows Communication Foundation (WCF) has two major modes for providing security (Transport and Message) and a third mode (TransportWithMessageCredential) that combines the two. This topic discusses message security and the reasons to use it.
What Is Message Security?
Message security uses the WS-Security specification to secure messages. The WS-Securityspecification describes enhancements to SOAP messaging to ensure confidentiality, integrity, and authentication at the SOAP message level (instead of the transport level).
In brief, message security differs from transport security by encapsulating the security credentials and claims with every message along with any message protection (signing or encryption). Applying the security directly to the message by modifying its content allows the secured message to be self-containing with respect to the security aspects. This enables some scenarios that are not possible when transport security is used.
Reasons to Use Message Security
In message-level security, all of the security information is encapsulated in the message. Securing the message with message-level security instead of transport-level security has the following advantages:
• End-to-end security. Transport security, such as Secure Sockets Layer (SSL) only secures messages when the communication is point-to-point. If the message is routed to one or more SOAP intermediaries (for example a router) before reaching the ultimate receiver, the message itself is not protected once an intermediary reads it from the wire. Additionally, the client authentication information is available only to the first intermediary and must be re-transmitted to the ultimate receiver in out-of-band fashion, if necessary. This applies even if the entire route uses SSL security between individual hops. Because message security works directly with the message and secures the XML in it, the security stays with the message regardless of how many intermediaries are involved before it reaches the ultimate receiver. This enables a true end-to-end security scenario.
• Increased flexibility. Parts of the message, instead of the entire message, can be signed or encrypted. This means that intermediaries can view the parts of the message that are intended for them. If the sender needs to make part of the information in the message visible to the intermediaries but wants to ensure that it is not tampered with, it can just sign it but leave it unencrypted. Since the signature is part of the message, the ultimate receiver can verify that the information in the message was received intact. One scenario might have a SOAP intermediary service that routes message according the Action header value. By default, WCF does not encrypt the Action value but signs it if message security is used. Therefore, this information is available to all intermediaries, but no one can change it.
• Support for multiple transports. You can send secured messages over many different transports, such as named pipes and TCP, without having to rely on the protocol for security. With transport-level security, all the security information is scoped to a single particular transport connection and is not available from the message content itself. Message security makes the message secure regardless of what transport you use to transmit the message, and the security context is directly embedded inside the message.
• Support for a wide set of credentials and claims. The message security is based on the WS-Security specification, which provides an extensible framework capable of transmitting any type of claim inside the SOAP message. Unlike transport security, the set of authentication mechanisms, or claims, that you can use is not limited by the transport capabilities. WCF message security includes multiple types of authentication and claim transmission and can be extended to support additional types as necessary. For those reasons, for example, a federated credentials scenario is not possible without message security. For more information about federation scenarios WCF supports, see Federation and Issued Tokens.
Transport security, such as Secure Sockets Layer (SSL) only secures
messages when the communication is point-to-point. If the message is
routed to one or more SOAP intermediaries (for example a router)
before reaching the ultimate receiver, the message itself is not
protected once an intermediary reads it from the wire.
Misleading. A network router or switch (OSI Layer 2 and 3) will not have access to the message content if encrypted with Transport layer security (Server side SSL certificate) since the service side SSL certificate is needed to decrypt the message. Transport layer security secures the message between the client and intended destination IP address since only the destination service provider is assumed to have the SSL private certificate which is required to decrypt the message. A SOAP intermediary would only be able to read the content if the SOAP intermediary (i.e. ESB) was in fact the intended message destination that actually establishes the encrypted transport channel with the client, ensuring a secure channel from client to server regardless of the number of network hops, routers and switches, etc (OSI layers 2 and 3).
Message Level security would add security to the message and could encrypt parts of a message if a middleware ESB (intended SOAP Intermediary) needed to read parts of a message to make routing decisions (Content Based Routing) but shouldn't be able to read other parts of a message that should only be accessed by downstream systems.
With transport use are securing the channel you are using, and with message the message (content) you are sending.
I have read in Training Kit of MS -WCF that all the bindings by default provide network security that is developer has to do nothing for implementing security.
I have one query over this :- I have used netTcpBinding and i send various objects from client to server. When sending objects we send a special guid in one of the properties of object which we again verify at Server before processing the request.
I will like to know what all vulnerabilities are involved, if do not do anything explicitly for Security, that is no transport level security is applied.
One more point we are using NetTcpBinding at Internet.
netTcpBinding is normally used for Intranet where you are likely to have point to point comms so transport security is probably adequate.
If you are operating over the web then you will want to enable Message level security to secure the end to end traffic (transport security will only secure the content for 1 hop). The default security for netTcpBinding is transport security so you need to change this.
In both cases message privacy (encryption), integrity(against tampering) and partial authentication is achieved.
NetTcpBinding I believe defaults to Windows authentication - so you will need an account in a domain or actually on the Service machine (if operating in a Workgroup) matching the Windows credentials of the client.
Note that you can programmatically change request the credentials from the client and set them programmatically before opening the client proxy if need be.
Also enable reliable messaging.