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Detection rules › Kusto

Mimecast Audit - Logon Authentication Failed

Severity
high
Time window
30m
Source
github.com/Azure/Azure-Sentinel

Detects threat when logon authentication failure found in audit

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1110 Brute Force

Rule body kusto

id: f00197ab-491f-41e7-9e22-a7003a4c1e54
name: Mimecast Audit - Logon Authentication Failed
description: Detects threat when logon authentication failure found in audit
displayName: Mimecast Audit - Logon Authentication Failed
severity: High
requiredDataConnectors:
  - connectorId: MimecastAuditAPI
    dataTypes:
      - MimecastAudit  
enabled: true
query: |
  MimecastAudit 
  | where ['Source IP'] !="" and ['Audit Type'] == "Logon Authentication Failed"
  | extend   SourceIp = ['Source IP'] 
queryFrequency: 30m
queryPeriod: 30m
triggerOperator: gt
triggerThreshold: 3
suppressionDuration: 5h
suppressionEnabled: false
tactics:
- Discovery
- InitialAccess
- CredentialAccess
relevantTechniques:
- T1110
alertRuleTemplateName:
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: true
    reopenClosedIncident: false
    lookbackDuration: P7D
    matchingMethod: AllEntities
eventGroupingSettings:
  aggregationKind: SingleAlert
alertDetailsOverride:
customDetails:
entityMappings:
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SourceIp
- entityType: Mailbox
  fieldMappings:
  - identifier: MailboxPrimaryAddress
    columnName: User
- entityType: CloudApplication
  fieldMappings:
  - identifier: AppId
    columnName: Application
version: 1.0.1
kind: Scheduled

Stages and Predicates

Stage 1: source

MimecastAudit

Stage 2: where

| where ['Source IP'] !="" and ['Audit Type'] == "Logon Authentication Failed"

Stage 3: extend

| extend   SourceIp = ['Source IP']

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Audit Typeeq
  • Logon Authentication Failed transforms: cased

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
SourceIpextend