PulseConnectSecure - Potential Brute Force Attempts

let threshold = 20;
PulseConnectSecure
| where Messages contains "Login failed"
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), count() by User, Source_IP
| where count_ > threshold

tactics:
- CredentialAccess
name: PulseConnectSecure - Potential Brute Force Attempts
id: 34663177-8abf-4db1-b0a4-5683ab273f44
requiredDataConnectors:
- connectorId: SyslogAma
  datatypes:
  - Syslog
query: |
  let threshold = 20;
  PulseConnectSecure
  | where Messages contains "Login failed"
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), count() by User, Source_IP
  | where count_ > threshold  
relevantTechniques:
- T1110
description: |
    'This query identifies evidence of potential brute force attack by looking at multiple failed attempts to log into the VPN server'
triggerOperator: gt
queryPeriod: 1h
severity: Low
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: User
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: Source_IP
  entityType: IP
version: 1.0.4
triggerThreshold: 0
kind: Scheduled
queryFrequency: 1h
status: Available
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Pulse Connect Secure/Analytic Rules/PulseConnectSecureVPN-BruteForce.yaml

{
  "$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/34663177-8abf-4db1-b0a4-5683ab273f44')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/34663177-8abf-4db1-b0a4-5683ab273f44')]",
      "properties": {
        "alertRuleTemplateName": "34663177-8abf-4db1-b0a4-5683ab273f44",
        "customDetails": null,
        "description": "'This query identifies evidence of potential brute force attack by looking at multiple failed attempts to log into the VPN server'\n",
        "displayName": "PulseConnectSecure - Potential Brute Force Attempts",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "User",
                "identifier": "FullName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "Source_IP",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Pulse Connect Secure/Analytic Rules/PulseConnectSecureVPN-BruteForce.yaml",
        "query": "let threshold = 20;\nPulseConnectSecure\n| where Messages contains \"Login failed\"\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), count() by User, Source_IP\n| where count_ > threshold\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Low",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CredentialAccess"
        ],
        "techniques": [
          "T1110"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}