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
queryPeriod: 5m
triggerOperator: GreaterThan
eventGroupingSettings:
  aggregationKind: SingleAlert
name: CTERA Mass Deletions Detection Analytic
id: 5365f294-0c67-432a-bacf-b1282a3b6c46
suppressionEnabled: false
customDetails:
  TenantName: TenantName
  UserName: UserName
  Share: Share
  RootPath: RootPath
  EdgeFiler: EdgeFiler
version: 1.0.0
tactics:
- Impact
triggerThreshold: 5000
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
queryFrequency: 5m
severity: High
requiredDataConnectors:
- connectorId: CTERA
  dataTypes:
  - Syslog
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    matchingMethod: AllEntities
    lookbackDuration: PT5H
    reopenClosedIncident: false
    enabled: false
status: Available
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CTERA/Analytic Rules/MassDeletions.yaml
relevantTechniques:
- T1485
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
kind: Scheduled
suppressionDuration: PT5H

ARM