Scenario: We have an Azure cloud environment that contains three (Prod,Test,Dev) PaaS database servers (PostgreSQL Flexible Servers). Each server exists in its own VNet. The SQL data tables found in each server contain sensitive information. Let's say we require an external user (eg. a contractor, consultant) to access the data tables in a secure way, with MFA enabled. What would be a secure & simple way of enabling this?
Some options I can think of:
Share database server credentials with external user (high risk of credentials being misplaced. No MFA option?):
Whitelist user IP address against Azure firewalls
Send PaaS server credentials to external user via email or SMS.
They connect using an SQL client on their machine.
External user to use VM via Bastion:
Add external user to Azure AD
Turn on MFA for user in AD
Create VM in Azure, with SQL client software installed (ie. pgAdmin for PostgreSQL)
Configure access to the 3 PaaS servers (Prod, test, dev) from the VM
Set up Bastion server with access to VM
Enable user to access VM via Bastion server
Second option incurrs extaa costs for the VM and Bastion of course. Are there any other methods I should consider?
Related
I'm deploying my first VM in azure but I can only connect from Azure Joined devices, and I have some external users without company laptops that need to connect,
To increase the security, I'm deploying access control with MFA for this machine.
Thanks.
When connecting a .net application to a local database we have always used a trusted connection connection string.
We are porting our platform over to Azure with:
Apps on Virtual Machines
Azure Domain Services
Sql Managed Instance
We have multiple Apps each run as a specific domain user and use trusted connection to the corresponding database on SQL Managed instance.
Attempting to use trusted connection from a domain joined virtual machine however (for example via SSMS results in the erro 'Azure Active Directory - Integrated' gives the error:
'Integrated Windows authentication supported only in federation flow.'
Looking at the Microsoft documentation it suggests it is possible to have trusted connections to SQL Managed Instance with 'seamless single sign-on' however the documentation only talks about an on premise domain connecting to Azure Active Directory.
Can anyone steer me in the right direction? are trusted connections possible in this setup? If not what is 'best practice' around connection strings to a SQL Managed Instance?
Thanks in advance
The best practice for Azure-native applications is to use Managed Identities to connect to Managed Instance. See eg: Connecting from your application to resources without handling credentials
Each Azure Virtual Machine, App Service App, Function App, etc can be provisioned with an AAD identity. Code running then can generate access tokens for resources (like Managed Instance) without ever touching a password or client secret.
Several Authentication strategies have been added to the SQL Client libraries to facilitate this. Or you can use Azure.Identity, or the local managed identity token endpoint library to fetch your own access token, and leverage that in the SQL Server client.
An alternative for lift-and-shift apps is to use Domain-joined VMs and use Windows Authentication for Managed Instance. This lets you continue to use traditional "Trusted Connection=true" from your VMs running in Azure to Managed Instance.
For security concerns I'm planning to not allow Azure services to communicate with Azure services but the services it is only working with.
For example, I've some web apps that uses Azure SQL Databases. Should I only add the outbound IP addresses of Azure Web Apps in the Azure SQL server firewall?
or I need to do something else?
This is not as easy as it should be. SQL Azure is not designed to be virtual network friendly so your only options are "Allow all Azure services" or hard-coded IPs. Unless your web apps have static IPs however, this won't be possible without writing a custom updater for the database which picks up IP address changes.
You could install a SQL server onto a VM and use virtual private networks, otherwise, make sure the login credentials are secure and accept the fact that an Azure client from anyone could attempt to connect to your database server.
The best way to lock down your SQL Database is with AAD Integration, and Managed Service Identities. Azure will provision an AAD identity for your application, and only code running in that application will be able to generate an Access Token for that Identity. Then you can provision it as an AAD user in your SQL Server.
This has the (large) added benefit of removing the secrets from the application, so you don't have to configure your application with a Client Secret, or a SQL Login/Password.
You can also run your App on a VNet, and configure your SQL firewall to only permit access from that VNet using Virtual Network service Endpoints For Azure SQL Database.
Or use the newer and much better Private Link for Azure SQL Database.
Some of the ways to secure the connection to the sql database that could be considered in this case are -
As you mentioned you are already thinking of configuring a firewall to whitelist the allowed IP addresses. The firewall could be configured both on the sql server level and the database level(we can use SSMS to configure the firewall at the database level).
We can encrypt data. Of course this would be encryption at rest. And the good news is the application connecting to the database need not change to query encrypted data.
The third way would be the traditional way(even if we were not using azure db) we would prevent unauthorized access by creating users/roles/permissions.
A very nice feature I found Azure db provides is the Threat Detection Capability. If you turned that on we would be notified of the possible vulnerabilities of the current db/server setup. And also where can we make improvements to fix those issues.
Connect your Azure function with your SQL DB using private endpoints and VNET integration. Your app service will need to be standard or premium. Even Premium function plan will do. This LINK talks about it.
Authenticate your azure function on your SQL DB using managed identities. See this link for info on how to do that. Managed identities
In short yes.
You can possibly make this more secure by creating vnet connection from the web app and creating a service endpoint for SQL. I'm not sure that will work, but worth a try.
I work in a small startup that is only hosted in Azure and I was wondering the best way to secure everything.
I use the below services
Web Apps (public facing)
Virtual machines - Running apps and services
Sql Sever
Service Bus
Storage Account.
The web apps and the Vms need to communicate with the other three services.
Below is what we are currently doing. Is this correct and if not can you provide any resources to work from?
Service bus - This is currently accessed using the connection string and is stored in the app settings of the web app and VM.
Storage Account - This is currently accessed using the connection string and is stored in the app settings of the web app and VM.
Sql server - This is currently using the firewall to Allow access to Azure Services plus restricting it to client machines that need to access the DB's through SSMS
VM - this is restricted using Network Security Groups to only allow client machines to RDP on.
I would appreciate any help that can be provided.
Edit
Things that i am worried about are:
Sql Server allow access to azure. I can turn this off but then the website will need to be added to the firewall and as i understand it the ip address is not static. Is it a security concern to leave this on?
Storage accounts, the connection string allows unlimited access to the account. You can lock this down with SAS to ip addresses but it has the same issues as the sqlsvr when connecting from the website. Also the SAS is time based how is it renewed?
Sql Server allow access to azure. I can turn this off but then the website will need to be added to the firewall and as i understand it the ip address is not static. Is it a security concern to leave this on?
By default, “Allow access to Azure services” is turned on, enabling this feature would allow any traffic from resources/services hosted in Azure to access the database.
Storage accounts, the connection string allows unlimited access to the account. You can lock this down with SAS to ip addresses but it has the same issues as the sqlsvr when connecting from the website. Also the SAS is time based how is it renewed?
A shared access signature can take one of two forms: Ad hoc SAS and SAS with stored access policy. We could re-specify the start time, expiry time, and permissions to get a new ad hoc SAS. When we associate a SAS with a stored access policy, the SAS inherits the constraints - the start time, expiry time, and permissions - defined for the stored access policy, we could modify the stored access policy to revoke the SAS or get a new SAS based on new stored access policy.
For more information about Shared Access Signatures (SAS), you could read this article.
Regarding access to the SQL server from your web apps:
They are using up to four outbound IP addresses when connecting to external services. You could limit the SQL server access to those.
Read this article to find them.
That won't completely close down foreign access to the SQL server, other people's web apps are using the same four outbound IP addresses.
Is there a way to connect from a web app (azure app service) to a SQL Server VM in Azure using Windows authentication? I'm not exactly sure if I need to impersonate or if the app needs to run under the identity that has access to the DB on the SQL Server.
I believe that you can do this - but you will need to share a Active Directory between the two - or have then in a private network together so that they are in the same broadcast subnet.
If you need to use your own Active Directory the create a network and a VPN to your site.
If you don't need to use Active Directory then use SQL Auth.
Looks like it is not possible, although it may be with Azure SQL. But not a VM running MSSQL. Ref links below.
SQL Server Integrated Security from an Azure Web Site
https://azure.microsoft.com/en-us/documentation/articles/sql-database-aad-authentication/