Base64 encoded Windows process command-lines (Normalized Process Events)

imProcessCreate
  | where CommandLine contains "TVqQAAMAAAAEAAA"
  | where isnotempty(Process)
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Dvc, ActorUsername, Process, CommandLine, ActingProcessName, EventVendor, EventProduct
  | extend timestamp = StartTimeUtc, AccountCustomEntity = ActorUsername, HostCustomEntity = Dvc

queryFrequency: 1d
triggerOperator: gt
tactics:
- Execution
- DefenseEvasion
description: |
  'Identifies instances of a base64 encoded PE file header seen in the process command line parameter.
  To use this analytics rule, make sure you have deployed the [ASIM normalization parsers](https://aka.ms/ASimProcessEvent)'  
relevantTechniques:
- T1059
- T1027
- T1140
name: Base64 encoded Windows process command-lines (Normalized Process Events)
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimProcess/imProcess_base64_encoded_pefile.yaml
severity: Medium
triggerThreshold: 0
version: 1.1.1
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: AccountCustomEntity
- entityType: Host
  fieldMappings:
  - identifier: FullName
    columnName: HostCustomEntity
tags:
- version: 1.0.0
  Id: ca67c83e-7fff-4127-a3e3-1af66d6d4cad
- Schema: ASIMProcessEvent
  SchemaVersion: 0.1.0
id: f8b3c49c-4087-499b-920f-0dcfaff0cbca
requiredDataConnectors: []
kind: Scheduled
query: |
  imProcessCreate
    | where CommandLine contains "TVqQAAMAAAAEAAA"
    | where isnotempty(Process)
    | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Dvc, ActorUsername, Process, CommandLine, ActingProcessName, EventVendor, EventProduct
    | extend timestamp = StartTimeUtc, AccountCustomEntity = ActorUsername, HostCustomEntity = Dvc  
queryPeriod: 1d

{
  "$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/f8b3c49c-4087-499b-920f-0dcfaff0cbca')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/f8b3c49c-4087-499b-920f-0dcfaff0cbca')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "Base64 encoded Windows process command-lines (Normalized Process Events)",
        "description": "'Identifies instances of a base64 encoded PE file header seen in the process command line parameter.\nTo use this analytics rule, make sure you have deployed the [ASIM normalization parsers](https://aka.ms/ASimProcessEvent)'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "imProcessCreate\n  | where CommandLine contains \"TVqQAAMAAAAEAAA\"\n  | where isnotempty(Process)\n  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Dvc, ActorUsername, Process, CommandLine, ActingProcessName, EventVendor, EventProduct\n  | extend timestamp = StartTimeUtc, AccountCustomEntity = ActorUsername, HostCustomEntity = Dvc\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Execution",
          "DefenseEvasion"
        ],
        "techniques": [
          "T1059",
          "T1027",
          "T1140"
        ],
        "alertRuleTemplateName": "f8b3c49c-4087-499b-920f-0dcfaff0cbca",
        "customDetails": null,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "AccountCustomEntity"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "HostCustomEntity"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimProcess/imProcess_base64_encoded_pefile.yaml",
        "tags": [
          {
            "Id": "ca67c83e-7fff-4127-a3e3-1af66d6d4cad",
            "version": "1.0.0"
          },
          {
            "Schema": "ASIMProcessEvent",
            "SchemaVersion": "0.1.0"
          }
        ],
        "templateVersion": "1.1.1"
      }
    }
  ]
}