Potential Password Spray Attack

let FailureThreshold = 15;
let FailedEvents = Okta_CL
| where eventType_s =~ "user.session.start"and outcome_reason_s in ("VERIFICATION_ERROR","INVALID_CREDENTIALS")
| summarize dcount(actor_alternateId_s) by client_ipAddress_s, bin(TimeGenerated, 5m)
| where dcount_actor_alternateId_s > FailureThreshold
| project client_ipAddress_s, TimeGenerated;
Okta_CL
| where eventType_s =~ "user.session.start"and outcome_reason_s in ("VERIFICATION_ERROR","INVALID_CREDENTIALS")
| summarize Users = make_set(actor_alternateId_s) by client_ipAddress_s, City = column_ifexists('client_geographicalContext_city_s', ""), Country = column_ifexists('client_geographicalContext_country_s', ""), bin(TimeGenerated, 5m)
| join kind=inner (FailedEvents) on client_ipAddress_s, TimeGenerated
| sort by TimeGenerated desc
| extend timestamp = TimeGenerated, IPCustomEntity = client_ipAddress_s

queryFrequency: 1h
entityMappings:
- entityType: IP
  fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
severity: Medium
triggerThreshold: 0
relevantTechniques:
- T1110
query: |
  let FailureThreshold = 15;
  let FailedEvents = Okta_CL
  | where eventType_s =~ "user.session.start"and outcome_reason_s in ("VERIFICATION_ERROR","INVALID_CREDENTIALS")
  | summarize dcount(actor_alternateId_s) by client_ipAddress_s, bin(TimeGenerated, 5m)
  | where dcount_actor_alternateId_s > FailureThreshold
  | project client_ipAddress_s, TimeGenerated;
  Okta_CL
  | where eventType_s =~ "user.session.start"and outcome_reason_s in ("VERIFICATION_ERROR","INVALID_CREDENTIALS")
  | summarize Users = make_set(actor_alternateId_s) by client_ipAddress_s, City = column_ifexists('client_geographicalContext_city_s', ""), Country = column_ifexists('client_geographicalContext_country_s', ""), bin(TimeGenerated, 5m)
  | join kind=inner (FailedEvents) on client_ipAddress_s, TimeGenerated
  | sort by TimeGenerated desc
  | extend timestamp = TimeGenerated, IPCustomEntity = client_ipAddress_s  
id: e27dd7e5-4367-4c40-a2b7-fcd7e7a8a508
triggerOperator: gt
version: 1.0.2
requiredDataConnectors:
- connectorId: OktaSSO
  dataTypes:
  - Okta_CL
description: |
    'This query searches for failed attempts to log into the Okta console from more than 15 various users within a 5 minute timeframe from the same source. This is a potential indication of a password spray attack'
queryPeriod: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Okta Single Sign-On/Analytic Rules/PasswordSpray.yaml
status: Available
name: Potential Password Spray Attack
tactics:
- CredentialAccess
kind: Scheduled

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/e27dd7e5-4367-4c40-a2b7-fcd7e7a8a508')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/e27dd7e5-4367-4c40-a2b7-fcd7e7a8a508')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "Potential Password Spray Attack",
        "description": "'This query searches for failed attempts to log into the Okta console from more than 15 various users within a 5 minute timeframe from the same source. This is a potential indication of a password spray attack'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let FailureThreshold = 15;\nlet FailedEvents = Okta_CL\n| where eventType_s =~ \"user.session.start\"and outcome_reason_s in (\"VERIFICATION_ERROR\",\"INVALID_CREDENTIALS\")\n| summarize dcount(actor_alternateId_s) by client_ipAddress_s, bin(TimeGenerated, 5m)\n| where dcount_actor_alternateId_s > FailureThreshold\n| project client_ipAddress_s, TimeGenerated;\nOkta_CL\n| where eventType_s =~ \"user.session.start\"and outcome_reason_s in (\"VERIFICATION_ERROR\",\"INVALID_CREDENTIALS\")\n| summarize Users = make_set(actor_alternateId_s) by client_ipAddress_s, City = column_ifexists('client_geographicalContext_city_s', \"\"), Country = column_ifexists('client_geographicalContext_country_s', \"\"), bin(TimeGenerated, 5m)\n| join kind=inner (FailedEvents) on client_ipAddress_s, TimeGenerated\n| sort by TimeGenerated desc\n| extend timestamp = TimeGenerated, IPCustomEntity = client_ipAddress_s\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CredentialAccess"
        ],
        "techniques": [
          "T1110"
        ],
        "alertRuleTemplateName": "e27dd7e5-4367-4c40-a2b7-fcd7e7a8a508",
        "customDetails": null,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "IPCustomEntity"
              }
            ]
          }
        ],
        "status": "Available",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Okta Single Sign-On/Analytic Rules/PasswordSpray.yaml",
        "templateVersion": "1.0.2"
      }
    }
  ]
}