Excessive Failed Authentication from Invalid Inputs

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Id	c775a46b-21b1-46d7-afa6-37e3e577a27b
Rulename	Excessive Failed Authentication from Invalid Inputs
Description	Creates an incident in the event that a user generates an excessive amount of failed authentications due to invalid inputs, indications of a potential brute force.
Severity	Medium
Tactics	CredentialAccess
Techniques	T1110
Required data connectors	SyslogAma
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Symantec VIP/Analytic Rules/ExcessiveFailedAuthenticationsfromInvalidInputs.yaml
Version	1.0.4
Arm template	c775a46b-21b1-46d7-afa6-37e3e577a27b.json

KQL

let threshold = 15;
SymantecVIP
| where isnotempty(RADIUSAuth)
| where RADIUSAuth =~ "Reject"
| summarize Total = count() by bin(TimeGenerated, 15m), User, ClientIP
| where Total > threshold

YAML

kind: Scheduled
triggerThreshold: 0
requiredDataConnectors:
- datatypes:
  - Syslog
  connectorId: SyslogAma
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: User
    identifier: FullName
- entityType: IP
  fieldMappings:
  - columnName: ClientIP
    identifier: Address
relevantTechniques:
- T1110
status: Available
tactics:
- CredentialAccess
name: Excessive Failed Authentication from Invalid Inputs
queryFrequency: 1h
id: c775a46b-21b1-46d7-afa6-37e3e577a27b
severity: Medium
queryPeriod: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Symantec VIP/Analytic Rules/ExcessiveFailedAuthenticationsfromInvalidInputs.yaml
version: 1.0.4
description: |
    'Creates an incident in the event that a user generates an excessive amount of failed authentications due to invalid inputs, indications of a potential brute force.'
query: |
  let threshold = 15;
  SymantecVIP
  | where isnotempty(RADIUSAuth)
  | where RADIUSAuth =~ "Reject"
  | summarize Total = count() by bin(TimeGenerated, 15m), User, ClientIP
  | where Total > threshold  
triggerOperator: gt

ARM