Zscaler - Unexpected ZPA session duration

Back


Id	e07846e0-43ad-11ec-81d3-0242ac130003
Rulename	Zscaler - Unexpected ZPA session duration
Description	Detects Unexpected ZPA session duration.
Severity	Medium
Tactics	InitialAccess
Techniques	T1078 T1133
Required data connectors	ZscalerPrivateAccess
Kind	Scheduled
Query frequency	1h
Query period	24h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Zscaler Private Access (ZPA)/Analytic Rules/ZscalerZPAUnexpectedSessionDuration.yaml
Version	1.0.0
Arm template	e07846e0-43ad-11ec-81d3-0242ac130003.json

KQL

let dt_lookBack = 24h;
let time_treshhold = timespan(08:00:00);
let open_sessions =
ZPAEvent
| where TimeGenerated > ago(dt_lookBack)
| where DvcAction == 'open'
| summarize timestampstart = min(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
| sort by timestampstart asc;
let closed_sessions =
ZPAEvent
| where TimeGenerated > ago(dt_lookBack)
| where DvcAction == 'close'
| summarize timestampend = max(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
| sort by timestampend asc;
open_sessions
| join (closed_sessions) on DstUserName, SrcIpAddr, NetworkSessionId
| extend duration = timestampend - timestampstart
| where duration > time_treshhold
| where DstUserName !has "ZPA LSS"
| sort by timestampstart asc
| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName

YAML

name: Zscaler - Unexpected ZPA session duration
status: Available
triggerThreshold: 0
severity: Medium
tactics:
- InitialAccess
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Zscaler Private Access (ZPA)/Analytic Rules/ZscalerZPAUnexpectedSessionDuration.yaml
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountCustomEntity
    identifier: Name
- entityType: IP
  fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
queryPeriod: 24h
queryFrequency: 1h
version: 1.0.0
triggerOperator: gt
description: |
    'Detects Unexpected ZPA session duration.'
query: |
  let dt_lookBack = 24h;
  let time_treshhold = timespan(08:00:00);
  let open_sessions =
  ZPAEvent
  | where TimeGenerated > ago(dt_lookBack)
  | where DvcAction == 'open'
  | summarize timestampstart = min(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
  | sort by timestampstart asc;
  let closed_sessions =
  ZPAEvent
  | where TimeGenerated > ago(dt_lookBack)
  | where DvcAction == 'close'
  | summarize timestampend = max(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
  | sort by timestampend asc;
  open_sessions
  | join (closed_sessions) on DstUserName, SrcIpAddr, NetworkSessionId
  | extend duration = timestampend - timestampstart
  | where duration > time_treshhold
  | where DstUserName !has "ZPA LSS"
  | sort by timestampstart asc
  | extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName  
relevantTechniques:
- T1078
- T1133
id: e07846e0-43ad-11ec-81d3-0242ac130003
requiredDataConnectors:
- dataTypes:
  - ZPAEvent
  connectorId: ZscalerPrivateAccess
kind: Scheduled

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/e07846e0-43ad-11ec-81d3-0242ac130003')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/e07846e0-43ad-11ec-81d3-0242ac130003')]",
      "properties": {
        "alertRuleTemplateName": "e07846e0-43ad-11ec-81d3-0242ac130003",
        "customDetails": null,
        "description": "'Detects Unexpected ZPA session duration.'\n",
        "displayName": "Zscaler - Unexpected ZPA session duration",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountCustomEntity",
                "identifier": "Name"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IPCustomEntity",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Zscaler Private Access (ZPA)/Analytic Rules/ZscalerZPAUnexpectedSessionDuration.yaml",
        "query": "let dt_lookBack = 24h;\nlet time_treshhold = timespan(08:00:00);\nlet open_sessions =\nZPAEvent\n| where TimeGenerated > ago(dt_lookBack)\n| where DvcAction == 'open'\n| summarize timestampstart = min(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId\n| sort by timestampstart asc;\nlet closed_sessions =\nZPAEvent\n| where TimeGenerated > ago(dt_lookBack)\n| where DvcAction == 'close'\n| summarize timestampend = max(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId\n| sort by timestampend asc;\nopen_sessions\n| join (closed_sessions) on DstUserName, SrcIpAddr, NetworkSessionId\n| extend duration = timestampend - timestampstart\n| where duration > time_treshhold\n| where DstUserName !has \"ZPA LSS\"\n| sort by timestampstart asc\n| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT24H",
        "severity": "Medium",
        "status": "Available",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1078",
          "T1133"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}