Tag: Blob

Automate and Deploy Microsoft Defender Advanced Threat Protection (MDATP) via PowerShell

A few days ago, I needed to on-board Azure Windows Server VMs with Microsoft Windows Defender Advanced Threat Protection, or in short, MDATP. Sometimes Azure Security Center (ASC) has issues with on-boarding VMs and deploying the MDATP agent. As a result, I wrote the following PowerShell script that will download the MDATP.cmd file from my Azure Blob container and install it locally to the VM. This script allows you to automate it for many VMs to the scope of a Resource Group.

Now there are a few assumptions here…

  1. Download the MDATP.cmd file from the Defender Security Center portal
  2. Remove the requirement for user consent for the MDATP execution
  3. Upload the modified MDATP file to an Azure Blob container
  4. Generated a SAS URI for the MDATP file

There are many examples on the Internet on how to go step #4. Maybe in time I will do another post.

To remove the requirement of the MDATP agent to execute based on user interaction/consent can be done by removing, or commenting out the following lines of code. Launch the MDATP.cmd file within Notepad, and add a “:” before each line of code from lines 9 through 19, except line 14. Should look something like this.

Now, update and run the following PowerShell code. You can validate the VM is calling back to the Defender Security Center portal or by running the MDATPClientAnalyzer on the VM.

#update resource as needed
$resourcegroup = "YOUR_RESOURCE_GROUP"
#get only Windows Server VMs
$vms = Get-AzVM -ResourceGroupName $resourcegroup | Where-Object {$_.StorageProfile.OSDisk.OSType -eq "Windows"} | Select-Object Name
foreach ($vm in $vms)
{
    #friendly start message to indicate which server has started
    Write-Host "Server $vm has started..."
    #create folder, do not display error if folder already exists
    New-Item -Path "C:\" -Name "MDATP" -ItemType "directory" -ErrorAction SilentlyContinue
    #download MDATP.cmd file from Storage Account with SAS URI. Execute the cmd file. Passing "Y" to continue with installation.
    Invoke-WebRequest -Uri "YOUR_URI_SAS" -OutFile WindowsDefenderATPLocalOnboardingScript.cmd; Start-Process -FilePath "C:\MDATP\WindowsDefenderATPLocalOnboardingScript.cmd" -Verb RunAs
    #sleep for 5 seconds
    Start-Sleep -Seconds 5
    #restart-server
    Restart-Computer -ComputerName $vm
    #friendly finished message to indicate which server has completed and will now reboot
    Write-Host "Server $vm has completed, reboot initiated..."
}

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Deploy an Azure Cloud Witness for your Failover Cluster Quorum for Windows Server 2016 & 2019

For the longest time, when deploying a cluster with Windows Server, you only had the two options,

  1. Using a dedicated disk for the quorum, or
  2. Configuring an SMB file-share as the quorum witness

With Server 2016 and 2019, there is now a third option, Cloud Witness. The Cloud Witness leverages Azure Blob storage to provide that additional cluster/quorum vote.

Before showing you how this is done, one should understand the purpose of a witness/quorum is with respect to a failover cluster.

When one or more members of a cluster stops reporting to the other cluster members, there is a vote. The vote ensures that there is no split-vote, and ensures the cluster has a true owner. For example, in a two node cluster, if each node believe it is the owner, then this will cause a “split-brain”. In short, neither node will ever agree it is the owner (or not). This is where a quorum is required to determine who is the owner by providing the third vote, ie. majority. This ensures the cluster has a true owner by having the majority of votes. Each member gets a vote, plus the quorum.

Why this matters, in the even there is no quorum, a node from the cluster can be evicted and as a result will suspend all application services to prevent data corruption by more than one system writing data without the cluster services coordinating data writes and access. Depending on policies, VMs running on the ejected cluster member will either suspend operations or be migrated to other nodes before being ejected.

Below is a step-by-step guide on how to configure the Azure Blob storage as the Cloud Witness.

Assumptions:

  • The Azure Blob storage account has already been created,
  • The cluster with at least 2 nodes already exists.

Launching the Failover Manager within Windows Server manager, connect to the cluster, and do the following. Right click the cluster object and select More Actions > Configure Cluster Quorum Settings…

Next select the Advanced Quorum configuration..

Ensure we have all the nodes selected, as seen below.

Next, select the Configure a Cloud Witness:

Now we need to get our Azure Blob storage account name, and its primary account key. This can be retrieved from the Azure portal.

Now validate the settings and complete the configuration.

Now if we go back to the Failover Manager console we can see we have successfully configured cluster with a Cloud Witness.

In conclusion, deploying a Cloud Witness for a Failover Cluster is very simple, and in case of power outage in one datacenter, maintenance on a node, etc. then the entire cluster and its members (nodes) are all given an equal opportunity. Not only is it recommended and a requirement for 2-node clusters, but for any number of nodes, having a quorum is key ensuring high-availability.  As mentioned, there are the traditional options such as using a dedicated disk or a file-share (SMB) as the cluster witness. However with Azure Blob storage with its 16×9 uptime, we can always ensure the quorum witness is online and available.