Released: February 2023 Exchange Server Security Updates

Nino_Bilic

Thank you for the workaround. But will it be necessary to revert the workaround after the fix is installed? Or are there any side effects, which can be caused by this in the future? What will be recommended?

Just in case: Would this small script be enough to undo the workaround? (Is the ordering right?) Thanks in advance.

# Load all Exchange Server names
$servers = (Get-ExchangeServer).Name

# On all Exchange-Servers...
Invoke-Command -ComputerName $servers -ScriptBlock {
  # Delete item from registry
  Remove-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\ExchangeServer\v15\Diagnostics' -Name 'DisableBaseTypeCheckForDeserialization' -Confirm:$false -ErrorAction SilentlyContinue
}

$servers | ForEach-Object { 
  # "Refresh" configuration, so that the workaround won't be used anymore
  Get-ExchangeDiagnosticInfo -Process Microsoft.Exchange.Directory.TopologyService -Component VariantConfiguration -Argument Refresh -Server $_ 
}

# Restart IIS on all Exchange Servers
Invoke-Command -ComputerName $servers -ScriptBlock { iisreset }

# Remove Setting Override (will delete object from AD)
Remove-SettingOverride -Identity "Adding learning location ClientExtensionCollectionFormatter" -Confirm:$false