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

OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CTERA/Analytic Rules/MassDeletions.yaml
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  
description: This analytic rule detects and alerts when large amount of deletion operations generated by the CTERA Edge Filer
severity: High
requiredDataConnectors:
- dataTypes:
  - Syslog
  connectorId: CTERA
incidentConfiguration:
  groupingConfiguration:
    lookbackDuration: PT5H
    reopenClosedIncident: false
    enabled: false
    matchingMethod: AllEntities
  createIncident: true
eventGroupingSettings:
  aggregationKind: SingleAlert
name: CTERA Mass Deletions Detection Analytic
triggerThreshold: 5000
version: 1.0.0
customDetails:
  EdgeFiler: EdgeFiler
  Share: Share
  UserName: UserName
  RootPath: RootPath
  TenantName: TenantName
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: UserName
    identifier: Name
- entityType: File
  fieldMappings:
  - columnName: EdgeFiler
    identifier: Name
tactics:
- Impact
alertDetailsOverride:
  alertnameFormat: CTERA Batch Access Denied Detection
  alertDescriptionFormat: |
        Detected {{Count}} denied access attempts by user {{UserName}} on Edge Filer  {{EdgeFiler}} within 5 minutes. Please investigate unauthorized access attempts or misconfigurations.
relevantTechniques:
- T1485
triggerOperator: GreaterThan
kind: Scheduled
id: 5365f294-0c67-432a-bacf-b1282a3b6c46
status: Available
suppressionEnabled: false
queryFrequency: 5m
queryPeriod: 5m
suppressionDuration: PT5H

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"
    }
  ]
}