Revocation of the SSL certificate failed for AAD authentication

by Contributed | Apr 20, 2021 | Technology

This article is contributed. See the original author and article here.

User may get the following security alert on certificate resigning SSL when trying to connect with any of the AAD options from SSMS:

“Revocation information for the security certificate for this site is not available. Do you want to proceed?”

Yes No View Certificate
 

This happens when a client using Internet Explorer (IE) sends a request to an Online Certificate Status Protocol (OCSP ) server to verify if the certificate has been revoked. If the IE browser is configured to expect an OCSP response and it’s not able to determine the revocation status of the certificate, the user gets prompted with the above security alert.  Chrome is not affected because it disabled OCSP checks by default in 2012, due to latency and privacy issues.

Mitigation steps:

To fix Server certificate revocation failed problems, a workaround is to turn off this setting – “Check for server certification revocation” in IE options, which will disable this for all OAUTH negotiations system-wide. To disable this option, perform the following steps.

• Type gpedit.msc in windows search and click OK.


• Navigate to Computer Configuration > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Advanced Page or Internet Explorer > Tools > Internet options > Advanced
  check for server certificate revocation
  


• Uncheck “Check for server certificate revocation”. 


• Reboot the server.  *IMPORTANT: It takes effect after you restart your computer.


• Remove CRL/OCSP disk cache entries on the client machine. From the Windows command line run:
  

  > certutil -urlcache CRL delete
  > certutil -urlcache OCSP delete​



• Perform “Clear SSL state” in Internet Explorer > Internet Options > Content.


• 
  

  On the client machine run gpupdate /force in the CMD window to force update the group policy. You can apply the GPO under user configuration, so the corresponding registry change will be under HKEY_CURRENT_USER.

  
  


• 
  

  Open Registry Editor and go to the path HKEY_CURRENT_USERSOFTWAREPoliciesMicrosoftWindowsCurrentVersionInternet SettingsCertificateRevocation with REG_DWORD 0

  
  


• 
  

  Open IE and check the setting, it should be disabled.

  
  

Troubleshooting connectivity with AAD options:

Open a PowerShell with administrative rights from the troublemaking machine and run below commands.

#OPTION 1 – bypass SQL Azure DB to see if your communication works with Azure AD from your machine

> Install-Module MSOnline > Import-Module MSOnline > $Msolcred = Get-credential 
# use your federated credenaials (i.e john@contoso.com + password) 

> Connect-MsolService -Credential $MsolCred

and check the federated authentication group

> Get-MsolGroup -MaxResults 10 –Searchstring  mygroup@contoso.com | format-list   
# displays group info as it is represented in Azure AD (i.e. mygroup or check the individual user) 

> Get-MsolUser -UserPrincipalName john@contoso.com | format-list

You should see what is stored in Azure AD under a specific user or group alias/name.

#OPTION 2 – Check the minimum connectivity requirement

Check connectivity to AAD endpoint for Password and Integrated authentication:

> tnc login.windows.net  -port 443

Check connectivity to AAD endpoint for Universal with MFA authentication: 

> tnc login.microsoftonline.com -port 443

Note that additional endpoints might be required, depending on AAD and on-premises AD setup. Capturing and debugging network or Fiddler traces is what usually helps in those situations.

Additional points to check – Make sure the firewall configuration is correctly set up

• Check your firewall settings and make sure it allows communication with the above AAD endpoints: login.windows.net and login.microsoftonline.com.


• Ensure the AAD required ports are not blocked by the firewall.
  
  

Note: The above error is mostly triggered when using SSMS. Azure Data Studio doesn’t have this issue because it has a custom MFA implementation that doesn’t use an old embedded IE browser.

SecretManagement and accessing Linux VMs in Azure

by Contributed | Apr 20, 2021 | Technology

This article is contributed. See the original author and article here.

Hello folks,

A couple weeks ago I wrote about how I leveraged PowerShell SecretManagement to generalize a demo environment.  In that article I only talked about Windows virtual machines running in Azure.  However, my colleague Thomas Maurer revisited the topic in his article,  Stop typing PowerShell credentials in demos using PowerShell SecretManagement.  Thomas really concentrated on how the local Secret Store can help when you have demos of local scripts that need secrets, versus my article that concentrated more on how the SecretManagement module paired with the Az.KeyVault module can help manage not only demo environment but help manage local accounts across production environments.

In response to both these articles we got a lot of questions, so I decided to address one of them here.

Will it work for linux?

Absolutely, you can have PowerShell on Linux, and import the modules mentioned in the articles. 

• Microsoft.PowerShell.SecretManagement


• Microsoft.PowerShell.SecretStore

One of the differences that in most case we use SSH keys to access a VM running in Azure. And Azure has a couple ways of storing that information.  When creating a VM you can Generate one at deployment, upload your own, or use an existing one already in azure.

When using “Use existing one stored in Azure” it refers to a separate repo in azure different than Azure Key Vault.  It actually saves the key in a portal service SSK Keys.

The SSH Keys portal service does give you the ability to get the public key so you can connect to the appropriate VMs. 

In the production environment that I’m currently involved we do not allow public IP assigned to VMs without a proper business case.  I actually agree with this policy.  So, we use Azure Bastion.  Connecting  using Azure Bastion offers the possibility to use one of several ways to authenticate to the VMs. 

• Password


• SSH Private Key


• SSH Private Key from Local File


• SSH Private Key from Azure Key Vault

By using Azure Key Vault you can also manage the SSH keys by setting expiration dates, apply proper versioning, assign tags AND have them available to the Azure Bastion with the option of requesting the Passphrase.

Just like my previous article.  You can even schedule an Azure Automation task, or an Azure Function to monitor the expiration dates and renewregenerate the SSH Keys for you.

I used the same Azure automation as the last article with a new runbook to create the SSH keys for my environment and store them in Azure Key Vault

param(

    [string]$ResourceGroupName = "Secret-Demo",
    [string]$vaultname = "SecretDemoVault"

)
Disable-AzContextAutosave -Scope Process

$VERSION = "1.0"
$SecretStoreName = "AzKeyVault"
$currentDay = (get-date).ToString("dMyyyyhhmmtt")
$ExpirationDate = (GET-DATE).AddMonths(2)

Write-Output "Runbook started. Version: $VERSION at $currentDay"
Write-Output "---------------------------------------------------"

# Authenticate with your Automation Account
	$connection = Get-AutomationConnection -Name AzureRunAsConnection
    # Wrap authentication in retry logic for transient network failures
    $logonAttempt = 0
    while(!($connectionResult) -and ($logonAttempt -le 10))
    {
        $LogonAttempt++
        # Logging in to Azure...
        $connectionResult = Connect-AzAccount `
                                -ServicePrincipal `
                                -Tenant $connection.TenantID `
                                -ApplicationId $connection.ApplicationID `
                                -CertificateThumbprint $connection.CertificateThumbprint

        Start-Sleep -Seconds 30
    }

# Set Azure Context

    $AzureContext = Get-AzSubscription -SubscriptionId $connection.SubscriptionID
    $SubID = $AzureContext.id
    Write-Output "Subscription ID: $SubID"
    Write-Output "Resource Group: $ResourceGroupName"
    Write-Output "VaultName: $vaultname"
    Write-Output "Local store name: $SecretStoreName"

#Create Password

    $Length = 24
    $characters = @([char[]]@(48..57),[char[]]@(65..90),[char[]]@(97..122),@('!','#','%','^','*','(',')','-','+','/','{','}','~','[',']'))
    $SSH_KEY_PASSWORD = ($Characters | Get-Random -Count $Length ) -join ''

# Register keyvault

Register-SecretVault -Name $SecretStoreName -ModuleName Az.KeyVault -VaultParameters @{ AZKVaultName = $vaultname; SubscriptionId = $SubID }

# create key and set it in Key Vault

$KeyPath = $env:TEMP
Write-Output "Key File path: $KeyPath"


New-RSAKeyPair -Length 2048 -Password $password -Path $KeyPathid_rsa -Force

$SSH_PRIVATE_KEY = Get-Content $KeyPath/id_rsa
$SSH_PUBLIC_KEY = Get-Content $KeyPath/id_rsa.pub
$SSH_PUBLIC_PEM = Get-Content $KeyPath/id_rsa.pem


Write-Output "SSH Passphrase: $SSH_KEY_PASSWORD"
Write-Output "SSH private Key: $SSH_PRIVATE_KEY"
Write-Output "SSH public Key - pub: $SSH_PUBLIC_KEY"
Write-Output "SSH public Key - pem: $SSH_PUBLIC_PEM"


Set-Secret -Name "SSH-Passphrase-demo" -Secret $SSH_KEY_PASSWORD -Vault $SecretStoreName
Set-Secret -Name "SSH-PrivateKey-demo" -Secret $SSH_PRIVATE_KEY -Vault $SecretStoreName
Set-Secret -Name "SSH-PublicKey-demo" -Secret $SSH_PUBLIC_KEY -Vault $SecretStoreName
Set-Secret -Name "SSH-PublicKeypem-demo" -Secret $SSH_PUBLIC_PEM -Vault $SecretStoreName

Please note that this runbook uses the New-RSAKeyPair cmdlet from the  PEMEncrypt module imported in my Automantion environment from the PowerShell Galery.

Now, again this is a proof-of-concept piece of code. For production use a lot of changes would be required (not an exhaustive list)

• Expiration dates you be set.


• A function to validate that the afore mentioned expiration is not imminent.


• A function to update the key on each Linux VM in a set environment.


• …

So, in conclusion,  yes,  you can use these new module on a Linux VM of you can use these new modules to help you manage the access to these VMs.

I hope this helps.

Cheers!

CSI: Redmond Episode 1 “Mistaken Identity”

by Contributed | Apr 19, 2021 | Technology

This article is contributed. See the original author and article here.

CSI: Redmond –  Episode 1 “Mistaken Identity”