UniFi Site Manager IPS signature count dropped 50

Unifi_SiteManager_Sites_CL
      | where TimeGenerated > ago(7d)
| extend rulesCount = toint(SiteStatistics.gateway.ipsSignature.rulesCount)
      | where isnotnull(rulesCount)
      | summarize MaxCount = max(rulesCount), arg_max(TimeGenerated, rulesCount) by SiteId, SiteName
      | where MaxCount > 100 and toreal(rulesCount) / MaxCount < 0.5
      | extend DropPct = round(100.0 * (1 - toreal(rulesCount) / MaxCount), 1)
      | extend Activity = strcat('IPS rules dropped to ', rulesCount, ' (from ', MaxCount, ', -', DropPct, '%)')
      | project TimeGenerated, SiteId, SiteName, Activity, CurrentRules = rulesCount, PeakRules = MaxCount, DropPct

version: 1.0.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/UniFi%20Site%20Manager%20%28CCF%29/Analytic%20Rules/UniFiCloudIPSsignaturecountdropped50.yaml
triggerThreshold: 0
requiredDataConnectors:
- dataTypes:
  - Unifi_SiteManager_Sites_CL
  connectorId: UniFiSiteManagerConnectorDefinition
tactics:
- DefenseEvasion
relevantTechniques:
- T1562
kind: Scheduled
incidentConfiguration:
  groupingConfiguration:
    matchingMethod: AllEntities
    lookbackDuration: PT12H
    reopenClosedIncident: false
    enabled: true
  createIncident: true
entityMappings:
- fieldMappings:
  - identifier: HostName
    columnName: SiteId
  - identifier: DnsDomain
    columnName: SiteName
  entityType: Host
description: |
  Identifies when the IPS signature ruleset count drops by more than half versus the 7-day maximum, indicating broken threat-intel feeds or rollback.
triggerOperator: gt
status: Available
subTechniques:
- T1562.001
queryFrequency: 6h
id: aa188a24-783a-76a1-cd11-3bcac0e97de9
name: 'UniFi Site Manager: IPS signature count dropped >50%'
severity: Medium
query: |
  Unifi_SiteManager_Sites_CL
        | where TimeGenerated > ago(7d)
  | extend rulesCount = toint(SiteStatistics.gateway.ipsSignature.rulesCount)
        | where isnotnull(rulesCount)
        | summarize MaxCount = max(rulesCount), arg_max(TimeGenerated, rulesCount) by SiteId, SiteName
        | where MaxCount > 100 and toreal(rulesCount) / MaxCount < 0.5
        | extend DropPct = round(100.0 * (1 - toreal(rulesCount) / MaxCount), 1)
        | extend Activity = strcat('IPS rules dropped to ', rulesCount, ' (from ', MaxCount, ', -', DropPct, '%)')
        | project TimeGenerated, SiteId, SiteName, Activity, CurrentRules = rulesCount, PeakRules = MaxCount, DropPct
queryPeriod: 7d

{
  "$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/aa188a24-783a-76a1-cd11-3bcac0e97de9')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/aa188a24-783a-76a1-cd11-3bcac0e97de9')]",
      "properties": {
        "alertRuleTemplateName": "aa188a24-783a-76a1-cd11-3bcac0e97de9",
        "customDetails": null,
        "description": "Identifies when the IPS signature ruleset count drops by more than half versus the 7-day maximum, indicating broken threat-intel feeds or rollback.\n",
        "displayName": "UniFi Site Manager: IPS signature count dropped >50%",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "SiteId",
                "identifier": "HostName"
              },
              {
                "columnName": "SiteName",
                "identifier": "DnsDomain"
              }
            ]
          }
        ],
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "lookbackDuration": "PT12H",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/UniFi%20Site%20Manager%20%28CCF%29/Analytic%20Rules/UniFiCloudIPSsignaturecountdropped50.yaml",
        "query": "Unifi_SiteManager_Sites_CL\n      | where TimeGenerated > ago(7d)\n| extend rulesCount = toint(SiteStatistics.gateway.ipsSignature.rulesCount)\n      | where isnotnull(rulesCount)\n      | summarize MaxCount = max(rulesCount), arg_max(TimeGenerated, rulesCount) by SiteId, SiteName\n      | where MaxCount > 100 and toreal(rulesCount) / MaxCount < 0.5\n      | extend DropPct = round(100.0 * (1 - toreal(rulesCount) / MaxCount), 1)\n      | extend Activity = strcat('IPS rules dropped to ', rulesCount, ' (from ', MaxCount, ', -', DropPct, '%)')\n      | project TimeGenerated, SiteId, SiteName, Activity, CurrentRules = rulesCount, PeakRules = MaxCount, DropPct\n",
        "queryFrequency": "PT6H",
        "queryPeriod": "P7D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1562"
        ],
        "templateVersion": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}