PulseConnectSecure - CVE-2021-22893 Possible Pulse Connect Secure RCE Vulnerability Attack

let threshold = 3;
PulseConnectSecure
| where Messages contains "Unauthenticated request url /dana-na/"
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), count() by Source_IP
| where count_ > threshold

relevantTechniques:
- T1190
name: PulseConnectSecure - CVE-2021-22893 Possible Pulse Connect Secure RCE Vulnerability Attack
requiredDataConnectors:
- dataTypes:
  - Syslog
  connectorId: PulseConnectSecure
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: Source_IP
  entityType: IP
triggerThreshold: 0
id: d0c82b7f-40b2-4180-a4d6-7aa0541b7599
tactics:
- InitialAccess
version: 1.0.2
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/PulseConnectSecure/PulseConnectSecureVPN-CVE_2021_22893_Exploit.yaml
queryPeriod: 1h
kind: Scheduled
metadata:
  categories:
    domains:
    - Security - Threat Intelligence
  author:
    name: Sittikorn S
  support:
    tier: Community
  source:
    kind: Community
queryFrequency: 1h
severity: High
description: |
    'This query identifies exploitation attempts using Pulse Connect Secure(PCS) vulnerability (CVE-2021-22893) to the VPN server'
query: |
  let threshold = 3;
  PulseConnectSecure
  | where Messages contains "Unauthenticated request url /dana-na/"
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), count() by Source_IP
  | where count_ > threshold  
triggerOperator: gt

{
  "$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/d0c82b7f-40b2-4180-a4d6-7aa0541b7599')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/d0c82b7f-40b2-4180-a4d6-7aa0541b7599')]",
      "properties": {
        "alertRuleTemplateName": "d0c82b7f-40b2-4180-a4d6-7aa0541b7599",
        "customDetails": null,
        "description": "'This query identifies exploitation attempts using Pulse Connect Secure(PCS) vulnerability (CVE-2021-22893) to the VPN server'\n",
        "displayName": "PulseConnectSecure - CVE-2021-22893 Possible Pulse Connect Secure RCE Vulnerability Attack",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "Source_IP",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/PulseConnectSecure/PulseConnectSecureVPN-CVE_2021_22893_Exploit.yaml",
        "query": "let threshold = 3;\nPulseConnectSecure\n| where Messages contains \"Unauthenticated request url /dana-na/\"\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), count() by Source_IP\n| where count_ > threshold\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "High",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1190"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}