Microsoft releases Out-of-Band Patch for Exchange Server

Update: If you clicked on the links that go over how to test if you have been impacted and thought to yourself “None of this is PowerShell”. You would be right, I apologize, there is now a PowerShell solution so let’s link those here and, I don’t know….here?

Microsoft Exchange has multiple zero-day exploits right now. There are Remote code executions, Server-Side Request Forgeries, and Post-Authentication Arbitrary File Writes. Any one of these should send you to patch your Exchange immediately.  

Below is a list of the CVE’s that need to be patched. The patch is already available, so you might want to jump onto this as soon as possible.

CVE-2021-26855

CVE-2021-26857

CVE-2021-26858

CVE-2021-27065

These have already been exploited by a group called HAFNIUM, so knowing it is already out in the wild elevates the risk. If you want to dive into patching your exchange, check here. If you would like to read up on how the attack works and check if you are a victim of it, read here and here.

I can hear you, though. Ah, man! I don’t want to download and update these manually; there has to be a better way! I have some excellent news for you. PDQ Deploy and PDQ Inventory Can help you patch your exchange systems. In no time, we have a scanner that will let you know the last time your system patched or if you have an update pending. If you are looking to skip the information and get right to the installation, the following PowerShell should work for you.

This does require the pswindowsupdate module to work. Reading this should help you get that done.