In application gateway "Backend certificate is invalid", Do really require by app gateway to monitored the validity of backend server certificate?
As because we have seen due to this human error can be encounter, whereas application owner and Azure administrator should be aware of the working flow of the application. But although the certificate is invalid to-and-fro communication would be secure, hence its worthless of mentioning "HTTPS connection won't be secure unless the server's TLS/SSL certificate is valid" in Azure portal.
However now a days every organization looking for cost saving, whereas Administrators are working in shared model and if any production application missed to update certificate in-between, can cause the business loss.
Rather MS has to introduce server certificate profile in http setting, which accepts the default certificate no matter valid or invalid and monitoring only the secure connection for end-to-end encryption.
https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-backend-health-troubleshooting
Currently, for the TLS connection to work in Application gateway, you need to ensure that the TLS/SSL certificate meets the following conditions:
That the current date and time is within the "Valid from" and "Valid
to" date range on the certificate.
That the certificate's "Common Name" (CN) matches the host header in the request. For example, if the client is making a request to https://www.contoso.com/, then the CN must be www.contoso.com.
Refer : https://learn.microsoft.com/en-us/azure/application-gateway/ssl-overview
If the Trusted Root Certificate uploaded is expired or backend server certificate’s Common Name (CN) does not match with the Hostname entered in HTTP Settings, the probe (default or custom) will start marking the backend servers as Unhealthy so that the requests won’t be routed to them.
There is no other way available to get this working at the moment. If you wish you may leave your feedback in the below forum requesting the desired feature. All the feedback you share in these forums will be monitored and reviewed by the Microsoft engineering teams responsible for building Azure.
https://feedback.azure.com/d365community/forum/8ae9bf04-8326-ec11-b6e6-000d3a4f0789
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I'm using Angular 14 and the ngx-mqtt front-end lib.
Here's my connection string which works fine:
getEmqxCloudConnection(): IMqttServiceOptions {
return {
hostname: 'xx.xx.xx.182',
port: 8083,
path: '/mqtt',
clean: true, // retain
connectTimeout: 4000,
reconnectPeriod: 4000,
clientId: 'HarBrowserTest1',
username: 'myUser',
password: 'myPass',
protocol: 'ws',
connectOnCreate: false,
};
}
As per their Broker dashboard the available ports are:
Ports: 1883(mqtt), 8883(mqtts), 8083(ws), 8084(wss)
I have already imported our SSL Certificate into the EMQX Dashboard, yet when I change my conn string to port: 8084 and protocol: 'wss' - IT DOESN'T CONNECT !
They have some screenshots here showing their Client Tool, but for reason every one shows port=1883 (a mistake maybe). https://docs.emqx.com/en/cloud/latest/connect_to_deployments/mqttx.html#connection-configuration
In my Chrome browser network tab, here's what I see for the std insecure ws - A successful ws conn to the Mqtt Broker.
Here is the certificate UI which I used to imported the PEM-Encoded cert body and key:
This will most likely be down to the certificate you have used for the broker.
First unless you have created the certificate just right (using the correct SAN entries) that include the IP address as the principal for the certificate, then the connection will get rejected because the certificate doesn't match the hostname/IP address the broker is using to connect.
Second, if it is a self signed certificate then the browser will just reject it, unless you have manually imported the CA (or if it really is self signed the cert it's self) into the browsers trust store and marked it as trusted. The browser will NOT show you a warning and ask to accept for a WebSocket connection like it does with a webpage, it will just fail with an error in the console and nothing else.
P.S. - You should not hard code the client id in web apps, this is because client ids must be unique across ALL clients, so hardcoding it means that everybody that visits the page will use the same client id and each new connection will kick off the last one (and probably end up in a reconnect fight)
If you check the logs of EMQX, maybe you can get more helpful information.
The following are possible reasons for common TLS connection failures.
First of all, as mentioned in the previous answer, your certificate may have a domain name or IP address set as CN or SAN when it is issued, but the address you specified when connecting does not match the values of the CN and SAN fields.
In this case, the TLS client will think that the server you are connecting to may not be what you really expect, so it will refuse the connection.
We have three ways to solve it:
Turn off the verification of the peer certificate, if your client has this option. However, we do not recommend this as it increases the security risk.
Reissue a certificate that matches your server address
Set the SNI field (full name Server Name Indication) when the client connects, so that TLS will check whether the SNI matches the CN and SAN fields of the certificate, instead of your actual connection address.
The second possible reason is that your certificate path is incomplete, such as the lack of intermediate certificates, or the client does not specify a trusted root certificate, its keyword in the EMQX log is unknown_ca.
For more TLS error reasons, you can refer to SSL Connection Error.
In a browser environment, you should use a server certificate issued by a CA Signed than a self-signed certificate.
Self-Signed SSL Vs Trusted CA Signed SSL Certificate， see the https://cheapsslsecurity.com/blog/self-signed-ssl-versus-trusted-ca-signed-ssl-certificate/
I have configured mutual authentication on an Azure Application Gateway. Currently all client certificates issued by the intermediate CA (as configured on SSL profile) are accepted, but I only want a specific certificate to be granted access, ideally based on the subject of the client certificate. Making changes to the CA that issues the client certificate is not feasible in my case.
Options explored:
Use leaf certificate when configuring SSL profile: app gateway seems to ignore the leaf certificate; all client certificates issued by the intermediate CA are accepted.
Configure a rewrite rule action to pass a server variable (e.g. client_certificate_subject) to backend in a custom request header. This would require changing the backend to interpret the request header, which I’m trying to avoid.
Configure a rewrite rule condition to check server variable (e.g. client_certificate_subject) and conditionally take some action. Ideally the action should set the HTTP response code (without forwarding the request to backend) or rewrite to an error page generated by the app gateway (e.g. HTTP 401 unauthorized / 403 forbidden). Can this be done somehow?
WAF rules don’t seem like a viable option as they don’t have access to server variables
Hoping to find a way of configuring this requirement on the app gateway. Thanks.
I understand that you want to be able to allow specific certificates only based on their subject names etc., to be granted access by the Application Gateway.
You can't use a rewrite rule because in order to "get to" a rule in the first place you have to get through the listener and you can't get through the listener if you can't authenticate with mutual authentication.
At this point, the best way to avoid people from accessing App GW would be to not give the Leaf certificate so they cannot access the same.
Also please note that Application Gateway Mutual Authentication is in preview right now and therefore, it is intended for "Evaluation" and testing, and not production currently. Once it is GA, there will be options to have revocation lists and checks.
Hope this helps. Please do let us know if you have further questions. Thank you!
I have generated a self signed certificate .This self signed certificate is stored in server and accepts request only from clients which is having this self signed certificate is this acceptable. since this HTTPS endpoint is supposed to be used only from our custom HTTPS client I strongly feel that CA signing is not required .
But my colleagues are warning that Self signed certificate should not be used in production environment no matter what .what should I do ??
There is a whole infrastructure in place to manage the life-cycle of the certificates, it is called PKI (Public Key Infrastructure). The CA's are part of it, and help you manage the certificate issuance and revocation.
It is not advised to use self-signed certificates in production environment, because you loose the life-cycle management of the certificate. Lets say if the client is compromised, any one in possession of that self-signed certificate can talk to the server. There is no way you can manage to revoke that certificate or maintain the CRL.
The ideal solution/implementation in your case, will actually be issuing the clients their own PKCS12 from the CA as well, which means they will have their own private key (this might get expensive, if you have many clients). But this is most secure way of doing it. If you know a client is compromised, you can revoke that client's certificate from the CA, and if the client does certificate validation (ideally should), it should no longer be able to communicate with the server. You can simply decommission that client.
Just an idea
But if you are looking for cost effective way (since you mentioned internal calls), you could have your server issue P12's to the clients, and your server maintaining a record of which client has what certificate. This gives you little control of managing the clients. You could enable certificate based authentication on the server side for those services (the server will receive the subjectDN of the client), and by referring to the stored record, you can identify which client is trying to communicate. And if you want to disable that client from being served by the server, simple update the record.
But to answer your concern, it is not ideal to use self-signed certificate because, in real world, you should be able to manage the certificates in real time or near to real time, which will not be possible if you use self-signed certificates.
I have an asp.net mvc web app that has been running in production for about 4 years. Suddenly since about a week ago, I am getting this error being returned for all calls to 3rd-party secure API's:
System.Net.WebException: The underlying connection was closed: Could
not establish trust relationship for the SSL/TLS secure channel. --->
System.Security.Authentication.AuthenticationException: The remote
certificate is invalid according to the validation procedure.
This is for calls to SendGrid for sending emails, calls to Azure Blob Storage for uploading of documents, calls to Connect.io for logging.
I have managed to resolve the Azure Blob Storage problem temporarily by changing the connection string to use http instead of https.
Clearly something has broken on my app server, and I have no idea where to start looking.
Please help.
Edit:
Turns out I was using a sample library provided by one of my (lesser-used) 3rd party API's, and this library had an override of
System.Net.ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors)
which had it's own logic about what constitutes a valid certificate!!! AARGH!
This part become key information for your problem:
I am getting this error being returned for all calls to 3rd-party
secure API's
According to MSDN blog:
This error message is caused because the process is not being able to
validate the Server Certificate supplied by the Server during an HTTPS
(SSL) request. The very first troubleshooting step should be to see
if the server supplied certificate and every certificate in the chain
is trouble free.
Because it seems that one or more third party certificates are rejected, you may configure Trusted Roots part of your certificate trust lists to include all required third party CA as part of chain to work with secure APIs from trusted sources, including reissued certificates if any.
Further details: https://technet.microsoft.com/en-us/library/dn265983.aspx
NB (Optional):
As temporary measure, you can implement this certificate validation handler in WebRole.cs until all related third-party certificates has reissued (remember this setting will trust all issued certificates, hence it's not recommended for long term usage):
System.Net.ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;
Additional reference: http://robertgreiner.com/2013/03/could-not-establish-trust-relationship-for-the-ssl-tls-secure-channel/
Similar thing happened in our system. Our problem was TLS version. The SSL offload appliance was configured to accept only TLS 1.2. One week ago this configuration accepted all TLS versions 1.0 to 1.2.
We had to reconfigure .NET's SecurityProtocol settings like:
System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls12;
You can use this site to test which TLS version you are using: https://www.ssllabs.com/ssltest/index.html
Try to get some information about the certificate of the servers and see if you need to install any specific certs.
The server(s) may had a cert signed by a 3rd party CA which you hadn't trusted yet. The solution is to add that CA to the Trusted Root CA list.
The Application i am working on needs to connect to a webservice over https, The certificate is trusted and valid.
I have used NSURLConnection is previous projects to use soap over http
Can anybody please point the difference between the two above mentioned scenarios,
I also need to understand what exactly happens when connecting over https, is the certificate stored automatically on the device, how does ssl handshake happen.
Any Pointers in this direction will be really helpful.
Regards,
Ishan
I need some clarification. Is the certificate signed by Apple for use with notifications or is it signed by an SSL root certificate authority (like VeriSign)?
Apple signed certificates are only to be used with WebServer to Apple Server communications like the Apple Push Notification Service. They are not intended for iOS device to WebServer.
A SSL certificate signed by a SSL root certificate authority should just work.
I think you are looking for an HTTP over SSL/TLS primer. So, here it goes.
HTTP is an unencrypted channel. The request and response are in a plain text data stream. HTTPS is an encrypted channel. The request and response are in a data stream encrypted using a shared master key. The magic of SSL/TLS is how this encrypted channel is created.
First, the client and server say hello to each other (in a clear channel).
Next, the client downloads the server's public certificate (in a clear channel).
At this point, the client has some work to do. It needs to verify the certificate. It needs to know that it understands the certificate, that the date range is valid, that the certificate is signed by a trusted certificate authority, and that the certificate has not been revoked.
Now, the client knows that it can trust the server.
Next, It sends a few short messages encrypted with the public key of the server (which is in the server's public certificate). These messages can only be decrypted by the server's private key (which only the server knows about). These messages allow the client and the server to negotiate a master key.
Finally, the client and the server begin the normal HTTP request and response using the newly created encrypted channel.
I hope this is what you are looking for. For a more detailed description see: http://www.moserware.com/2009/06/first-few-milliseconds-of-https.html
If the certificate was issued by a chain of certificate authorities whose root is trusted by Apple, then there is nothing to do. The iOS device will accept the certificate, as long as it is otherwise valid (ie not expired, not revoked, etc).
If the CA chain's root is not trusted by Apple, you will need to download the root's certificate to the phone. This can be done (I think) via the iPhone Configuration Utility. Enterprise provisioning scenarios undoubtedly support this also.