I'm trying to get value from Azure Key Vault. It's working well in localhost but when we deploy to Azure App Service. it shows CORS Error:
Access to XMLHttpRequest at 'https://xxxxxxxx.azure-api.net/xxxxxx/api/xxx/xxxx' from origin 'https://xxxxxxx.azurewebsites.net' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
I'm using below code in my .Net Core Web API:
const string secretName = "XXXXXXXXXXXXXX";
var kvUri = $"https://xxxxxxxx.vault.azure.net";
var client = new SecretClient(new Uri(kvUri), new DefaultAzureCredential());
var secret = client.GetSecretAsync(secretName).GetAwaiter().GetResult().Value;
conString = secret.Value;
Thanks in advance
CORS isn't permitted for Key Vault at this time because it's not designed to be used by browsers. I spoke with the KV product team about this a good while back and created a UserVoice submission for this feature a few years ago: https://feedback.azure.com/forums/906355-azure-key-vault/suggestions/34753195-enable-cors-for-key-vault
Were you logged in to Azure when you tested this application locally?
Also for app service to access key vault you would need some authentication mechanism
like service principal or managed Identity.
You can check this link for your reference:
Access key vault from app service
Related
I got a blob storage which I use as website.
This blob has a system assigned managed identity.
This identity is added to a key vault as access policy.
So actually it should be able to access the secrets.
But when I try it the way microsoft documented it I got an error.
const getSecret = async () => {
var credential = new DefaultAzureCredential({
ManagedIdentityClientId: "<blob-id>",
} as DefaultAzureCredentialOptions)
const keyVaultName = "<key-vault-name>"
const url = "https://" + keyVaultName + ".vault.azure.net"
const client = new SecretClient(url, credential)
const secret = await client.getSecret("function-key")
}
I got the error
Error: DefaultAzureCredential is not supported in the browser. Use InteractiveBrowserCredential instead.
at Module.60308 (defaultAzureCredential.browser.js:5:34)
Is this even possible?
Thanks!
Please check this azure-sdk-for-js issue according to which ,
interactive credentials is recommended instead of default
credentials.And for client side applications that run in the browser,
the InteractiveBrowserCredential is the only credential type that is
supported.Please check this github reference
So for interactive credentials for Node.js, if a clientId is
provided, the Azure AD app need to be configured to have a "Mobile and desktop applications" as redirect endpoint instead of web. See
set up redirect uri
See DefaultAzureCredential and examples
Also according to DefaultAzureCredential Class | Microsoft Docs
The following credential types if enabled will be tried, in order:
EnvironmentCredential >ManagedIdentityCredential >
SharedTokenCacheCredential > VisualStudioCredential >
VisualStudioCodeCredential > AzureCliCredential>
AzurePowerShellCredential >InteractiveBrowserCredential: uses browser to auth users - not enabled by default. Pass true to the DefaultAzureCredential to enable it.
I'm experimenting with various Azure features and currently want to retrieve a secret from KeyVault.
Straight to the case:
I'm using this nuget package to interact with my azure resources.
I've developed a simple .NET Core console app and run it locally.
I have a KeyVault resource with one secret defined which is active and not expired.
I've registered an App in AAD so my locally shipped .NET Core console app has an identity within AAD.
Than I've created a "client secret" within this registered app in AAD to use it to authenticate myself as an app.
After that I've added access policy in my KeyVault resource to allow GET operation for secrets for this registered app:
Then I've developed a small piece of code which should retrieve the desired secret:
public class AzureAuthentication
{
public async Task<string> GetAdminPasswordFromKeyVault()
{
const string clientId = "--my-client-id--";
const string tenantId = "--my-tenant-id--";
const string clientSecret = "--my-client-secret--";
var credentials = new ClientSecretCredential(tenantId, clientId, clientSecret);
var client = new SecretClient(new Uri("https://mykeyvaultresource.vault.azure.net"), credentials);
var secret = await client.GetSecretAsync("admincreds");
return secret.Value.Value;
}
}
However when I'm trying to do this I'm getting an AccessDenied error:
Am I missing something painfully obvious here? Or there is some latency (>30 min for this moment) for which changes from Access policies screen in KeyVault resource are applied?
I test your code and Get permission, it works fine.
From your screenshot, it looks you didn't add the correct service principal related to the AD App to the Access policies.
If you add the service principal related to the AD App, it will appear as APPLICATION, not COMPOUND IDENTITY.
So when you add it, you could search for the client Id(i.e. application Id) or the name of your App Registration directly, make sure you add the correct one.
Make sure your AD App(service principal) has the correct permission in your keyvault -> Access policies
I'm working with Azure Key Vault and I'm testing the "Managed Identities" for Azure Resource. Long story short: with this feature we can easily access to a KeyVault secrets from (e.g.) VM, App Service... I wrote this simple code:
private void GetKeyVaultSecrets()
{
AzureServiceTokenProvider azureServiceTokenProvider = new AzureServiceTokenProvider();
var akvCallback = new KeyVaultClient.AuthenticationCallback(azureServiceTokenProvider.KeyVaultTokenCallback);
var keyVaultClient = new KeyVaultClient(akvCallback);
var secret = keyVaultClient.GetSecretAsync("https://mykeyvault.vault.azure.net/secrets/mySecret").GetAwaiter().GetResult();
string superSecret = secret.Value;
}
And I'm able to access my "Secret" without any kind of Authorization. Is it safe? Am I missing something? It looks so strange that with those 7 lines of code you have access to all your secrets. Thanks for your attention.
If you are running this on a service with a system-assigned Managed Identity, here's what actually happens (example for App Service, VM is slightly different):
Your app reads IDENTITY_ENDPOINT and IDENTITY_HEADER environment variables
HTTP call to IDENTITY_ENDPOINT using the IDENTITY_HEADER as authentication
This endpoint cannot be called from the outside, only from within the instance.
Its port is also random
In the call, your app specifies it wants a token for Key Vault (resource https://vault.azure.net)
The Managed Identity endpoint uses the certificate it has created to authenticate to Azure Active Directory with the Client Credentials flow
Azure AD verifies the request and issues a token
Managed Identity endpoint returns the token to your app
KeyVaultClient uses the token to authorize the call to Key Vault
On Virtual Machines, the Instance Metadata Service is used to get tokens.
The main thing to understand is that any process running on the instance itself is capable of getting tokens from the Managed Identity.
Though if you were to get malicious code running on your instance,
other approaches could be in trouble as well :)
If you run that code locally, it can work as well.
AzureServiceTokenProvider also attempts Visual Studio authentication as well as Azure CLI authentication.
So if you are logged in to e.g. AZ CLI, it is able to get an access token for your user to Azure Key Vault and access it.
Reference: https://learn.microsoft.com/en-us/azure/app-service/overview-managed-identity?context=azure%2Factive-directory%2Fmanaged-identities-azure-resources%2Fcontext%2Fmsi-context&tabs=dotnet#rest-protocol-examples
Example request done in VMs: https://learn.microsoft.com/en-us/azure/active-directory/managed-identities-azure-resources/tutorial-windows-vm-access-nonaad#access-data
I am trying to protect my backing services to my frontend webapp using MSI and AAD auth.
I keep getting a 401 when I call my backing services form the public facing webapp. I have added the public webapp as a reader in the IAM section of the backing services.
What I can't figure out is how to obtain the access token, it seems that no matter which endpoint I use for obtaining the access token, it says that it is not found.
Here is my code:
{
var azureServiceTokenProvider = new AzureServiceTokenProvider();
string accessToken = azureServiceTokenProvider.GetAccessTokenAsync("https://<mywebapi>.azurewebsites.net").GetAwaiter().GetResult();
var httpClient = new HttpClient();
httpClient.DefaultRequestHeaders.Authorization = new
AuthenticationHeaderValue("Bearer", accessToken);
RemoteIp = httpClient.GetStringAsync("https://<mywebapi>.azurewebsites.net/api/default/remoteIp").GetAwaiter().GetResult();
LocalIp = httpClient.GetStringAsync("https://<mywebapi>.azurewebsites.net/api/default/localIp").GetAwaiter().GetResult();
ConnectionId = httpClient.GetStringAsync("https://<mywebapi>.azurewebsites.net/api/default/connectionId").GetAwaiter().GetResult();
}
And here is the error message:
Parameters: Connectionstring: [No connection string specified], Resource: https://<mywebapi>.azurewebsites.net, Authority: .
Exception Message: Tried to get token using Managed Service Identity.
Unable to connect to the Managed Service Identity (MSI) endpoint.
Please check that you are running on an Azure resource that has MSI setup.
UPDATE:
<mywebapi> is obviously the actual endpoint value, but not exposed here on stackoverflow. Furthermore I should mention that calling the API endpoints directly works fine, after I have authorized with my personal credentials xxx#xxx.xxx. The issue is related to the webapp trying to identify itself to the webapi, even though it is a registered application which has been assigned the necessary IAM rights on the webapi resource.
The error says it tried to use MSI, but could not. Are you sure you are running this code on the Web App with MSI enabled?
Also, you need to replace "https://<mywebapi>.azurewebsites.net" with the App Id URI or Application Id of your API in Azure AD.
In other words, this needs to match the valid audience that you have configured for the API.
I have a Function App with Managed service identity (MSI) enabled.
I'm trying to use this Function App to access a secret from my Key Vault.
I have added the code into my Function App to retrieve the secret.
AzureServiceTokenProvider azureServiceTokenProvider = new AzureServiceTokenProvider();
var keyVaultClient = new KeyVaultClient(new KeyVaultClient.AuthenticationCallback(azureServiceTokenProvider.KeyVaultTokenCallback));
var secret = await keyVaultClient.GetSecretAsync("https://test-prototype-vault.vault.azure.net/secrets/batman/guidhere").ConfigureAwait(false);
I receive the following error:
Microsoft.Azure.WebJobs.Script: One or more errors occurred. Microsoft.Azure.KeyVault: Access denied.
I think this is because I need to (as described in the link above).
You may need to configure the target resource to allow access from
your application. For example, if you request a token to Key Vault,
you need to make sure you have added an access policy that includes
your application's identity.
I don't know how to do that. I have gone to my Key Vault and tried to add an Access Policy - I can't find the application to Select Principle option.
Setup of Azure Function.
What happens when I try to add the principal.
This blog has details but you need to go into key vault and give the function app access to secrets in a new access policy
https://medium.com/#jeffhollan/getting-key-vault-secrets-in-azure-functions-37620fd20a0b
The name of your function app should show in list of users