Detectionhightest

Exchange PowerShell Snap-Ins Usage

Detects adding and using Exchange PowerShell snap-ins to export mailbox data. As seen used by HAFNIUM and APT27

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FPT.EagleEye, Nasreddine Bencherchali (Nextron Systems)Created Wed Mar 03Updated Fri Mar 2425676e10-2121-446e-80a4-71ff8506af47windows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic
Detection Logic4 selectors
detection:
    selection_img:
        - Image|endswith:
              - '\powershell.exe'
              - '\pwsh.exe'
        - OriginalFileName:
              - 'PowerShell.EXE'
              - 'pwsh.dll'
    selection_cli:
        CommandLine|contains: 'Add-PSSnapin'
    selection_module:
        CommandLine|contains:
            - 'Microsoft.Exchange.Powershell.Snapin'
            - 'Microsoft.Exchange.Management.PowerShell.SnapIn'
    filter_msiexec:
        # ParentCommandLine: C:\Windows\System32\MsiExec.exe -Embedding C9138ECE2536CB4821EB5F55D300D88E E Global\MSI0000
        ParentImage: 'C:\Windows\System32\msiexec.exe'
        CommandLine|contains: '$exserver=Get-ExchangeServer ([Environment]::MachineName) -ErrorVariable exerr 2> $null'
    condition: all of selection_* and not 1 of filter_*
False Positives
Unknown

False positive likelihood has not been assessed. Additional context may be needed during triage.

Rule Metadata
Rule ID
25676e10-2121-446e-80a4-71ff8506af47
Status
test
Level
high
Type
Detection
Created
Wed Mar 03
Modified
Fri Mar 24
Path
rules/windows/process_creation/proc_creation_win_powershell_snapins_hafnium.yml
Raw Tags
attack.executionattack.t1059.001attack.collectionattack.t1114
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