Deleting messages org-wide with Exchange Online PowerShell
Why
Don’t have Defender P2 (so you can’t Threat Explore or manually delete messages) and need to get rid of some phishing messages batched out to your users? Not a problem (while Exchange Online PowerShell is around.)
How
PowerShell 7.4.2
$sender = "sender@domain.com"
$upn = "exchangeadmin@company.com"
$searchname = "${sender} spam"
Install-Module ExchangeOnlineManagement
Import-Module ExchangeOnlineManagement
Connect-ExchangeOnline -UserPrincipalName $upn
Connect-IPPSSession -UserPrincipalName $upn
New-ComplianceSearch -Name $searchname -ExchangeLocation All -ContentMatchQuery "(From:${sender})"
Start-ComplianceSearch -Identity $searchname
New-ComplianceSearchAction -SearchName $searchname -Purge -PurgeType harddelete
Optionally, block the sender’s address:
New-TenantAllowBlockListItems -ListType Sender -Block -Entries $sender -NoExpiration