To force a filter update we have a dedicated script:
Update-MalwareFilteringServer.ps1

This wraps the Forefront cmdlet Start-EngineUpdate that we already met when discussing Enable-AntimalwareScanning.ps1

Sometimes we may need to check if the automatic updating service is working. This is when we need the Forefront cmdlet:
Get-EngineUpdateInformation

Most importantly it provides us with the last update date/time and the current update version.

Another cmdlet encountered on enabling/disabling the filter was:
Get-AntiVirusScanSettings
Set-AntiVirusScanSettings

You may find the Enabled property useful when verifying the enablement status of the filter.

Malware Filtering Policy

The Malware Filtering Policy discussed in Exchange 2013 Malware Protection - Part 1 is configurable using the MalwareFilterPolicy Exchange cmdlets:
Get-MalwareFilterPolicy
Set-MalwareFilterPolicy

Again this is an Exchange cmdlet so loading the Forefront snap-in is not necessary. Looking closely at the returned properties we can see that almost all of them are configurable at: Exchange Administrative Centre | Protection | Malware | Default Policy, with the exception of:
BypassInboundMessages
BypassOutboundMessages

These allow us to disable filtering for inbound and outbound messages.

Final Tips

Although many would have preferred Microsoft to continue providing on-premises Forefront, others will be happy to get an important piece of this product out-of-the-box in Exchange 2013.

Today we used the shell to manage the Malware Filter. This is the administrative interface of choice whenever managing updates. Amongst others we saw how to enable/disable the filter, start an immediate filter update, configure the updating frequency and verify the current update version.

References

Exchange 2013 Malware Protection - Part 1