CTERA Mass Deletions Detection Analytic

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Id	5365f294-0c67-432a-bacf-b1282a3b6c46
Rulename	CTERA Mass Deletions Detection Analytic
Description	This analytic rule detects and alerts when large amount of deletion operations generated by the CTERA Edge Filer
Severity	High
Tactics	Impact
Techniques	T1485
Required data connectors	CTERA
Kind	Scheduled
Query frequency	5m
Query period	5m
Trigger threshold	5000
Trigger operator	GreaterThan
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CTERA/Analytic Rules/MassDeletions.yaml
Version	1.0.0
Arm template	5365f294-0c67-432a-bacf-b1282a3b6c46.json

KQL

Syslog
| where ProcessName == 'gw-audit'
| extend
    TenantName = extract("\"vportal\":\"([^\"]*)\"", 1, SyslogMessage),
    UserName = extract("user=([^|]*)", 1, SyslogMessage),
    Permission = extract("op=([^|]*)", 1, SyslogMessage),
    EdgeFiler = extract("\"client\":\"([^\"]*)\"", 1, SyslogMessage),
    RootPath = extract("rootPath=([^|]*)", 1, SyslogMessage),
    Share = extract("share=([^|]*)", 1, SyslogMessage),
    LocalPath = extract("path=([^|]*)", 1, SyslogMessage),
    Timestamp = todatetime(extract("\"@timestamp\":\"([^\"]*)\"", 1, SyslogMessage))
| where Permission == 'delete'
| summarize Count = count() by UserName, bin(Timestamp, 5m)
| where Count > 5000

YAML

entityMappings:
- fieldMappings:
  - columnName: UserName
    identifier: Name
  entityType: Account
- fieldMappings:
  - columnName: EdgeFiler
    identifier: Name
  entityType: File
triggerThreshold: 5000
severity: High
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    lookbackDuration: PT5H
    enabled: false
    matchingMethod: AllEntities
    reopenClosedIncident: false
queryFrequency: 5m
status: Available
suppressionEnabled: false
customDetails:
  TenantName: TenantName
  RootPath: RootPath
  Share: Share
  UserName: UserName
  EdgeFiler: EdgeFiler
relevantTechniques:
- T1485
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CTERA/Analytic Rules/MassDeletions.yaml
triggerOperator: GreaterThan
version: 1.0.0
id: 5365f294-0c67-432a-bacf-b1282a3b6c46
requiredDataConnectors:
- connectorId: CTERA
  dataTypes:
  - Syslog
alertDetailsOverride:
  alertDescriptionFormat: |
        Detected {{Count}} denied access attempts by user {{UserName}} on Edge Filer  {{EdgeFiler}} within 5 minutes. Please investigate unauthorized access attempts or misconfigurations.
  alertnameFormat: CTERA Batch Access Denied Detection
name: CTERA Mass Deletions Detection Analytic
suppressionDuration: PT5H
eventGroupingSettings:
  aggregationKind: SingleAlert
description: This analytic rule detects and alerts when large amount of deletion operations generated by the CTERA Edge Filer
query: |
  Syslog
  | where ProcessName == 'gw-audit'
  | extend
      TenantName = extract("\"vportal\":\"([^\"]*)\"", 1, SyslogMessage),
      UserName = extract("user=([^|]*)", 1, SyslogMessage),
      Permission = extract("op=([^|]*)", 1, SyslogMessage),
      EdgeFiler = extract("\"client\":\"([^\"]*)\"", 1, SyslogMessage),
      RootPath = extract("rootPath=([^|]*)", 1, SyslogMessage),
      Share = extract("share=([^|]*)", 1, SyslogMessage),
      LocalPath = extract("path=([^|]*)", 1, SyslogMessage),
      Timestamp = todatetime(extract("\"@timestamp\":\"([^\"]*)\"", 1, SyslogMessage))
  | where Permission == 'delete'
  | summarize Count = count() by UserName, bin(Timestamp, 5m)
  | where Count > 5000  
tactics:
- Impact
queryPeriod: 5m
kind: Scheduled

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/5365f294-0c67-432a-bacf-b1282a3b6c46')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/5365f294-0c67-432a-bacf-b1282a3b6c46')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "Detected {{Count}} denied access attempts by user {{UserName}} on Edge Filer  {{EdgeFiler}} within 5 minutes. Please investigate unauthorized access attempts or misconfigurations.\n",
          "alertnameFormat": "CTERA Batch Access Denied Detection"
        },
        "alertRuleTemplateName": "5365f294-0c67-432a-bacf-b1282a3b6c46",
        "customDetails": {
          "EdgeFiler": "EdgeFiler",
          "RootPath": "RootPath",
          "Share": "Share",
          "TenantName": "TenantName",
          "UserName": "UserName"
        },
        "description": "This analytic rule detects and alerts when large amount of deletion operations generated by the CTERA Edge Filer",
        "displayName": "CTERA Mass Deletions Detection Analytic",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "UserName",
                "identifier": "Name"
              }
            ]
          },
          {
            "entityType": "File",
            "fieldMappings": [
              {
                "columnName": "EdgeFiler",
                "identifier": "Name"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "SingleAlert"
        },
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": false,
            "lookbackDuration": "PT5H",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CTERA/Analytic Rules/MassDeletions.yaml",
        "query": "Syslog\n| where ProcessName == 'gw-audit'\n| extend\n    TenantName = extract(\"\\\"vportal\\\":\\\"([^\\\"]*)\\\"\", 1, SyslogMessage),\n    UserName = extract(\"user=([^|]*)\", 1, SyslogMessage),\n    Permission = extract(\"op=([^|]*)\", 1, SyslogMessage),\n    EdgeFiler = extract(\"\\\"client\\\":\\\"([^\\\"]*)\\\"\", 1, SyslogMessage),\n    RootPath = extract(\"rootPath=([^|]*)\", 1, SyslogMessage),\n    Share = extract(\"share=([^|]*)\", 1, SyslogMessage),\n    LocalPath = extract(\"path=([^|]*)\", 1, SyslogMessage),\n    Timestamp = todatetime(extract(\"\\\"@timestamp\\\":\\\"([^\\\"]*)\\\"\", 1, SyslogMessage))\n| where Permission == 'delete'\n| summarize Count = count() by UserName, bin(Timestamp, 5m)\n| where Count > 5000\n",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT5M",
        "severity": "High",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT5H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "techniques": [
          "T1485"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 5000
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}