I could not find any information on the safety of the Remote Desktop client ActiveX control AxMsRdpClient11NotSafeForScripting from mstsax.dll.
E.g. can a malicious RDP server execute code on the client or otherwise mess with the client state (e.g. pollute clipboard)?
If it can, is there a set of settings, that ensures client security against malicious server?
P.S. In my scenario the authenticity of the server is not important. All I need is the video stream of the remote desktop.
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I am creating simple application where I need get and fetch data to DB. As I find out from Xamarin app is standard using of HTTP request to DB instead of directly connect to DB.
I create Azure SQL DB, I create application with connection to this DB. But I cant really find out how it now should works.
There is no many tutorials or they are not fully described.
I read this one https://learn.microsoft.com/en-us/azure/app-service-mobile/app-service-mobile-xamarin-forms-get-started#download-and-run-the-xamarinforms-solution
I find many references on this one but it seems out of date. Everybody recommended download the project from section
Run the Xamarin.Forms solution
On the settings blade for your Mobile App, click Quickstart (under Deployment) > Xamarin.Forms. Under step 3, click Create a new app if it's not already selected. Next click the Download button.
Under this tab I have only references to next tutorials but not any to Project Download. (screenshot below)
https://imgur.com/THCdUE1
Can you give me some advice if I do something wrong? Or link to updated tutorials? I am little desperate from this
Many Thanks
Azure SQL is not an HTTP/s service-- it runs proprietary SQL Server protocol on port 1433, just like on-premise versions of SQL Server.
If you are trying to connect directly to SQL Server from a Xamarin App, you are almost certainly making a mistake. Doing so would require providing credentials to your Xamarin app that can connect directly to your database, which opens your database up for a malicious user to do pretty much whatever they want to. The reason this kind of 2-tier application is dangerous is because the Xamarin app runs on an untrusted device (your user's mobile device), and a malicious user can intercept any data that your application has in memory, including your database credentials. They can then use those credentials to gain access to your database. Unless you were to use unique database credentials for each user (very impractical) and setup very stringent security roles in SQL Server, it'd be impossible to keep a malicious user from accessing the database for all of your other users (which is very, very bad). The other problem is that many networks block traffic on port 1433, or only allow access via an HTTPS proxy server, so your application would not function on many networks if it tried to connect directly to SQL.
This is the answer to your question, but please don't do this:
If you are certain that you have taken care of the security correctly, you should be able to install the System.Data.SqlClient nuget package and use that to communicate with SQL Server as you would with any .NET application. Here's a code example from Microsoft.
This is my opinion on what you should do instead:
The correct way for most Xamarin applications to communicate with Azure SQL database would be via an intermediary application server.
If your application access data specific to a user, should have per-user credentials in it (username and password that get exchanged for an authorization token when the user logs in is a common technique). The Xamarin app would then use HTTPS to make requests to your application server using those user credentials. The application server would validate the user credentials (authenticate that they are legitimate and authorize the data being requested based on who the user is) and make requests to Azure SQL.
If your application only access public data anonymously, then you can make unauthenticated requests to your application server which will blindly request that data from Azure SQL and return it to your client (though it would also return the same data to any attacker on the internet, so be sure if you use this approach you intend all data served to be public to the world).
In both cases, your application server would be the only piece that communicates with Azure SQL. For a .NET application this would typically be done via System.Data.SqlClient or perhaps indirectly through an ORM like Entity Framreworks. The advantage to this 3-tier approach is that the untrusted client tier does not have unrestricted access to your database tier. Only the middle application server tier has the credentials for SQL Server, and it is trusted and runs in a secure environment (a server you manage, not an end-user's mobile device). This means that an attacker cannot intercept the database credentials and misuse them. It also means that your application only requires HTTPS data access to function, so your application will work on almost any network.
This is probably not the answer you are looking for, since it involves authoring an entire application server that has to be hosted by you (Azure App Service would be my recommendation, if you are already using Azure SQL). It also requires you to implement an API on the server, and then write an API client for your Xamarin application. This is no small amount of work.
I have purchased an SSL certificate and installed it using IIS on my remote system. So I can therefore access my remote system using https://myremotesite.co.uk. All is fine, it seems to work; users can register and login to my remote site and download my GUI to run my application which stores and retrieves data from my SQL Server database.
When a user runs my GUI to access my application it prompts them for their login-id and password and, if they are authenticated, my application pops up on their screen. All is well, it all seems to work fine.
However, I have read that access to the SQL Server database itself can be restricted with an SSL certificate and to do this I would need "Encrypt=yes" in the connection string which my GUI uses to check authentication.
Is it necessary for me to do this? Or is safe to just rely on the IIS HTTPS service? So my question is ... do I need to register my SSL certificate with BOTH IIS AND SQL Server or just ONE of them, and if so, which ONE?
Thanks for the answers thus far .. to explain further, the GUI connects to an IIS controlled website which has specific handlers written to perform a restricted set of database queries. So my database DOES reside on my server, but it only allows my server's (local) IIS to 'login' and insert, update and extract data.
Once the IIS website service has extracted data, it then returns the same to the GUI. So the GUI has no DIRECT access to the database. What I am concerned about is if - by some malicious means - the database was copied in its entirety ... could/should I use my SSL certificate to encrypt sensitive data in this event?
Silverlight application is sitting on a server which is accessible from internet and WebApi is sitting on a server behind firewall which is not accessible via internet but can be accessible via intranet. Both Silverlight Application Server and WebApi Server can talk in intranet. Is it possible for Silverlight application which is accessed from internet to talk to WebApi?
You simply need to add a firewall rule that allows Green Server to access Red Server at a given port. You can add MAC filters, IP filters, use an ad-hoc IP in a different subnet in the Red Server, expose the API in an unusual port (not 80), use client certificates, expose the API through SSL, and many other things to protect the server inside the firewall and the communication between servers.
That's the mission of the firewall. If not, you'd simply didn't connect the networks through the firewall.
Is there way to make the vb6 desktop application which is not on client network to communicate with sql server which is in the client premises?
A far better option (a necessity if the app is for general distribution) is to use an intermediary service, either over web/HTTP or some other (possibly custom) protocol.
If you app is specific to your company/employer for their internal use, then you will need to use a VPN or similar to allow it to work as if it was on the same internal network.
Note that opening up a database server to the wider internet is asking for trouble and should be avoided at all costs.
Easiest would be to use port forwarding on border router to SQL server.
Better would be to encrypt traffic to/from SQL Server like this: IPSec through NAT: Securing SQL Server remote connections
I need to transfer data daily from SQL Server (2008) to SQL Server (2005). One of the servers is located at our web host so the data will be transferred over the Internet. On the same network I would use SSIS to transfer the data, but over the Internet this is not a secure option. Is there a secure way of achieving this?
You can use SSL with SQL Server (2000/2005 Instructions / 2008 Instructions) and then force protocol encryption on the connection between both machines. You don't have to use a purchased SSL certificate either, you can use Windows Server Certificate Services to generate one - however if you do so then the CRL must be on a machine that both servers can connect to. An easy way to do this is install Certificate Services on a stand alone machine, perhaps just a VM and the configure it to embed a public DNS name for it's CRL. This doesn't have to be a machine running Certificate Services, just something you own and can upload to. Then you can generate the certificates and publish the CRL and tada, all done.
You will need to ensure the service account SQL is running as has access to the private key of the certificate it is using.
Generally it isn't recommended to have your SQL Servers exposed to the Internet, although that may be out of your control in this case. In your position I would investigate developing some separate Web Services that would perform the transfer of the data. These can then be secured using a variety of methods, such as SSL and WS-Security and other custom user permissions. If that isn't possible then blowdart's answer seems like the way to go.
You can use Service Broker:
Built into SLQ Server engine itself, no need for external process to drive communication.
Compatible protocol SQL 2005 and SQL 2008 communicate over Service Broker out-of-the box.
No need to expose either server to the internet. Through Message Forwarding you can expose
just a SQL Express, with no data on it, to the internet to act as a gateway that lets messages into the back end target.
Communication is encrypted.
Speed, the sample in the link shows how you can exchange over 5000 1k payload messages per second between commodity machines.
Unlike SSIS or replication Service Broker is a general communication framework so it won't provide support to extract the changes and to apply the changes, with conflict resolution and the like. You would have to code that part yourself.