VMware PowerCLI

VMSA-2022-0001 CD-ROM vulnerability patch workaround and Locked CD-ROM error

VMSA-2022-0001 CD-ROM vulnerability patch workaround and Locked CD-ROM error. See how to patch the CD-ROM vulnerability and CD-ROM locked

Highlights

  • The dangerous aspect of this vulnerability is an attacker able to access a virtual machine with the CD-ROM device emulation attached to the VM may be able to execute code at the hypervisor level, from the virtual machine.
  • If you can’t patch to a patch-released version, or if a patched version is not yet available as in the case of ESXi 7, first, let’s deploy the workaround for VMSA-2022-0001.
  • Let’s take a closer look at the VMSA-2022-0001 CD-ROM vulnerability patch workaround and discuss the details of how the various solutions are vulnerable, patches available, and workaround that can be put in place.

Well, closely on the heels of the Log4j vulnerability, we have started 2022 with a new VMSA-2022-0001 released from VMware. The new vulnerability affects a wide range of products, including VMware Workstation, Fusion, and ESXi. Let’s take a closer look at the VMSA-2022-0001 CD-ROM vulnerability patch workaround and discuss the details of how the various solutions are vulnerable, patches available, and workaround that can be put in place.

What is the new VMSA-2022-0001 CD-ROM vulnerability?

The new vulnerability comes from the built-in CD-ROM device emulation found in the following products:

  • VMware Workstation
  • VMware Fusion
  • VMware ESXi

It specifically relates to CVE-2021-22045 on VMware ESXi Hosts. You can find the KB that is linked in the table below here:

It is described as a heap-overflow vulnerability and is described as in the important category of criticality. The maximum CVSSv3 score is 7.7.

The dangerous aspect of this vulnerability is an attacker able to access a virtual machine with the CD-ROM device emulation attached to the VM may be able to execute code at the hypervisor level, from the virtual machine. VMware mentions, the exploit to be in conjunction with other issues to exploit. So, it is not clear exactly the attack path needed to carry out the exploit.

The TLDR; of this is that if your virtual machine looks like the below, it is vulnerable:

Vulnerable virtual machine in VMware vSphere to VMSA 2022 0001
Vulnerable virtual machine in VMware vSphere to VMSA 2022 0001

VMSA-2022-0001 CD-ROM vulnerability patch workaround and locked CD-ROM error

Note the following matrix of affected products and the links posted by VMware for workarounds and relevant patches that have already been released.

ProductVersionRunning OnCVE IdentifierCVSSv3SeverityFixed VersionWorkaroundsAdditional Documentation
ESXi7.0AnyCVE-2021-220457.7Important Patch PendingKB87249None
ESXi6.7AnyCVE-2021-220457.7Important ESXi670-202111101-SGKB87249None
ESXi6.5AnyCVE-2021-220457.7Important ESXi650-202110101-SGKB87249None
Workstation16.xAnyCVE-2021-220457.7Important 16.2.0KB87206None
Fusion12.xOS XCVE-2021-220457.7Important 12.2.0KB87207None

VMware Cloud Foundation is also affected, since it deploys ESXi as part of the solution:

ProductVersionRunning OnCVE IdentifierCVSSv3SeverityFixed VersionWorkaroundsAdditional Documentation
VMware Cloud Foundation (ESXi)4.xAnyCVE-2021-220457.7Important Patch PendingKB87249None
VMware Cloud Foundation (ESXi)3.xAnyCVE-2021-220457.7Important Patch PendingKB87249None

Deploying the workaround for VMSA-2022-0001

If you can’t patch to a patch-released version, or if a patched version is not yet available as in the case of ESXi 7, first, let’s deploy the workaround for VMSA-2022-0001. What does the workaround involve? It is actually pretty simple to work around the vulnerability. it involves the process of disconnecting your CD-ROM drive and setting this to the Client Device.

Thankfully, we have PowerCLI that is our best friend when it comes to performing manual, tedious tasks such as removing the CD-ROM drive from every single virtual machine in your inventory.

First, to see the virtual machine that ISO images or other CD-ROM configuration in place, run the following PowerCLI command:

Get-VM | Get-CDDrive | Where {$_.extensiondata.connectable.connected -eq $true} | Select Parent

To actually remove and disconnect an attached CD-ROM/DVD device, including an ISO image, run the following:

Get-VM | Get-CDDrive | Where {$_.extensiondata.connectable.connected -eq $true} | Set-CDDrive -NoMedia -confirm:$false
Running the PowerCLI commands to see which VMs are vulnerable to VMSA 2022 0001 and remove CD ROMs
Running the PowerCLI commands to see which VMs are vulnerable to VMSA 2022 0001 and remove CD ROMs

Problem with running PowerCLI on VMs to remove Locked CD-ROM

When you run the PowerCLI one-liner to remove the CD-ROM from all your VMs, you may run into a situation where some Linux VMs fail with the following message:

Operation failed to remove the CD ROM drive from your vSphere VMs
Operation failed to remove the CD ROM drive from your vSphere VMs

If you try to remove manually, you will see the underlying reason, the operating system has the CD-ROM locked:

CD ROM drive locked by the operating system
CD ROM drive locked by the operating system

Is there a way to prevent your VMs from waiting on the message to force the override of removing the CD-ROM? Yes, actually we can do this with a VM advanced setting, documented in the following VMware KB:

To set these advanced settings with PowerCLI, run:

$vms =  Get-VM
 
foreach ($vm in $vms) {
 
New-AdvancedSetting -Entity $vm -Name cdrom.showIsoLockWarning -Value False -Confirm:$false -Force:$true
New-AdvancedSetting -Entity $vm -Name msg.autoanswer -Value TRUE -Confirm:$false -Force:$true
 
}

After running the command to set the settings on your VMs, you can run your PowerCLI script to remove the CD-ROM drives.

Wrapping Up

The new VMSA-2022-0001 bulletin from VMware is certainly one that we need to give attention to and is a CVSSv3 7.7 scale vulnerability, so in the important range. Currently, there is not a patched version for vSphere 7, so will definitely need to employ the workaround of removing the CD-ROM drives from your vSphere 7 VMs. This will come in handy as well for environments that do have patched versions but that will need to schedule the time for maintenance.

As shown, the VMSA-2022-0001 CD-ROM vulnerability patch workaround requires running the PowerCLI script to remove devices. You may see issues with locked CD-ROM drives in Linux VMs. Using the advanced settings for the VMs to workaround this and PowerCLI one again to implement the fix, will allow getting around this roadblock to scripting out the workaround to remove the vulnerability until the environment is patched.

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Brandon Lee

Brandon Lee is the Senior Writer, Engineer and owner at Virtualizationhowto.com and has over two decades of experience in Information Technology. Having worked for numerous Fortune 500 companies as well as in various industries, Brandon has extensive experience in various IT segments and is a strong advocate for open source technologies. Brandon holds many industry certifications, loves the outdoors and spending time with family.

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