Identify MERCURY powershell commands

(union isfuzzy=true
(SecurityEvent
| where EventID == 4688
| where Process has_any ("powershell.exe","powershell_ise.exe","pwsh.exe") and CommandLine has_cs "-exec bypass -w 1 -enc"
| where CommandLine  contains_cs "UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA"
| extend timestamp = TimeGenerated, AccountCustomEntity = Account, HostCustomEntity = Computer, ProcessCustomEntity = Process
),
(DeviceProcessEvents
| where FileName =~ "powershell.exe" and ProcessCommandLine has_cs "-exec bypass -w 1 -enc"  
| where ProcessCommandLine contains_cs "UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA" 
| extend timestamp = TimeGenerated, AccountCustomEntity = AccountName, HostCustomEntity = DeviceName, ProcessCustomEntity = InitiatingProcessFileName
),
(imProcessCreate
| where Process has_any ("powershell.exe","powershell_ise.exe","pwsh.exe") and CommandLine has_cs "-exec bypass -w 1 -enc"
| where CommandLine  contains_cs "UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA"
| extend timestamp = TimeGenerated, AccountCustomEntity = ActorUsername, HostCustomEntity = DvcHostname, ProcessCustomEntity = Process
)
)

severity: High
triggerThreshold: 0
metadata:
  source:
    kind: Community
  support:
    tier: Community
  categories:
    domains:
    - Security - Threat Intelligence
  author:
    name: Ajeet Prakash
queryFrequency: 1d
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceProcessEvents
id: ce74dc9a-cb3c-4081-8c2f-7d39f6b7bae1
version: 1.0.1
name: Identify MERCURY powershell commands
kind: Scheduled
query: |
  (union isfuzzy=true
  (SecurityEvent
  | where EventID == 4688
  | where Process has_any ("powershell.exe","powershell_ise.exe","pwsh.exe") and CommandLine has_cs "-exec bypass -w 1 -enc"
  | where CommandLine  contains_cs "UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA"
  | extend timestamp = TimeGenerated, AccountCustomEntity = Account, HostCustomEntity = Computer, ProcessCustomEntity = Process
  ),
  (DeviceProcessEvents
  | where FileName =~ "powershell.exe" and ProcessCommandLine has_cs "-exec bypass -w 1 -enc"  
  | where ProcessCommandLine contains_cs "UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA" 
  | extend timestamp = TimeGenerated, AccountCustomEntity = AccountName, HostCustomEntity = DeviceName, ProcessCustomEntity = InitiatingProcessFileName
  ),
  (imProcessCreate
  | where Process has_any ("powershell.exe","powershell_ise.exe","pwsh.exe") and CommandLine has_cs "-exec bypass -w 1 -enc"
  | where CommandLine  contains_cs "UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA"
  | extend timestamp = TimeGenerated, AccountCustomEntity = ActorUsername, HostCustomEntity = DvcHostname, ProcessCustomEntity = Process
  )
  )  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/MultipleDataSources/powershell_mercury.yaml
queryPeriod: 1d
relevantTechniques:
- T1570
triggerOperator: gt
tactics:
- LateralMovement
tags:
- Mercury
- Schema: ASIMFileEvent
  SchemaVersion: 0.1.0
description: |
  'The query below identifies powershell commands used by the threat actor Mercury.
  Reference:  https://www.microsoft.com/security/blog/2022/08/25/mercury-leveraging-log4j-2-vulnerabilities-in-unpatched-systems-to-target-israeli-organizations/'  
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: AccountCustomEntity
- entityType: Host
  fieldMappings:
  - identifier: FullName
    columnName: HostCustomEntity
- entityType: Process
  fieldMappings:
  - identifier: ProcessId
    columnName: ProcessCustomEntity

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/ce74dc9a-cb3c-4081-8c2f-7d39f6b7bae1')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/ce74dc9a-cb3c-4081-8c2f-7d39f6b7bae1')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "Identify MERCURY powershell commands",
        "description": "'The query below identifies powershell commands used by the threat actor Mercury.\nReference:  https://www.microsoft.com/security/blog/2022/08/25/mercury-leveraging-log4j-2-vulnerabilities-in-unpatched-systems-to-target-israeli-organizations/'\n",
        "severity": "High",
        "enabled": true,
        "query": "(union isfuzzy=true\n(SecurityEvent\n| where EventID == 4688\n| where Process has_any (\"powershell.exe\",\"powershell_ise.exe\",\"pwsh.exe\") and CommandLine has_cs \"-exec bypass -w 1 -enc\"\n| where CommandLine  contains_cs \"UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA\"\n| extend timestamp = TimeGenerated, AccountCustomEntity = Account, HostCustomEntity = Computer, ProcessCustomEntity = Process\n),\n(DeviceProcessEvents\n| where FileName =~ \"powershell.exe\" and ProcessCommandLine has_cs \"-exec bypass -w 1 -enc\"  \n| where ProcessCommandLine contains_cs \"UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA\" \n| extend timestamp = TimeGenerated, AccountCustomEntity = AccountName, HostCustomEntity = DeviceName, ProcessCustomEntity = InitiatingProcessFileName\n),\n(imProcessCreate\n| where Process has_any (\"powershell.exe\",\"powershell_ise.exe\",\"pwsh.exe\") and CommandLine has_cs \"-exec bypass -w 1 -enc\"\n| where CommandLine  contains_cs \"UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA\"\n| extend timestamp = TimeGenerated, AccountCustomEntity = ActorUsername, HostCustomEntity = DvcHostname, ProcessCustomEntity = Process\n)\n)\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "LateralMovement"
        ],
        "techniques": [
          "T1570"
        ],
        "alertRuleTemplateName": "ce74dc9a-cb3c-4081-8c2f-7d39f6b7bae1",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "columnName": "AccountCustomEntity",
                "identifier": "FullName"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "columnName": "HostCustomEntity",
                "identifier": "FullName"
              }
            ],
            "entityType": "Host"
          },
          {
            "fieldMappings": [
              {
                "columnName": "ProcessCustomEntity",
                "identifier": "ProcessId"
              }
            ],
            "entityType": "Process"
          }
        ],
        "tags": [
          "Mercury",
          {
            "Schema": "ASIMFileEvent",
            "SchemaVersion": "0.1.0"
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/MultipleDataSources/powershell_mercury.yaml",
        "templateVersion": "1.0.1"
      }
    }
  ]
}