Vectra AI Detect - Suspected Compromised Host

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Id	60eb6cf0-3fa1-44c1-b1fe-220fbee23d63
Rulename	Vectra AI Detect - Suspected Compromised Host
Description	Create an incident when a Host is suspected to be compromised. The higher the severity level is, the more immediate attention it requires as Vectra AI engine is more confident that this is a real threat. Level of severity are: Low, Medium, High, Critical). Recommended configuration is to trigger an alert for at least High and Critical.
Severity	Informational
Tactics	CredentialAccess Discovery LateralMovement Collection CommandAndControl Exfiltration Impact
Techniques	T1003 T1087 T1021 T1119 T1071 T1041 T1499
Required data connectors	CefAma
Kind	Scheduled
Query frequency	5m
Query period	5m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Vectra AI Detect/Analytic Rules/VectraDetect-Host-by-Severity.yaml
Version	1.0.9
Arm template	60eb6cf0-3fa1-44c1-b1fe-220fbee23d63.json

KQL

// Edit this variable to only keep the Severity level where an incident needs to be created (Defaults are: "High", "Critical" ). Possible values are: "Low", "Medium", "High", "Critical"
let configured_level = dynamic(["High", "Critical"]);
CommonSecurityLog
| where DeviceVendor == "Vectra Networks"
| where DeviceProduct == "X Series"
| where DeviceEventClassID == "hsc"
| project-rename threat_score = FlexNumber1
| project-rename certainty_score = FlexNumber2
| project-rename vectra_URL = DeviceCustomString4
| project-rename detection_name = DeviceEventClassID
| project-rename score_decreases = DeviceCustomString3
| extend level = case( threat_score <  50 and certainty_score < 50, "Low",
                      threat_score < 50 and certainty_score >= 50 , "Medium", 
                      threat_score >= 50 and certainty_score <= 50, "High", 
                      threat_score >= 50 and certainty_score >= 50, "Critical",
                      "UNKNOWN")
| extend Severity = case(level == "Info", "Informational",level == "Critical", "High", level)
| where level in (configured_level) 
//keep only the event with the highest threat score per Host
| summarize arg_max(TimeGenerated, *) by SourceHostName
| sort by TimeGenerated

YAML

kind: Scheduled
eventGroupingSettings:
  aggregationKind: AlertPerResult
alertDetailsOverride:
  alertSeverityColumnName: Severity
  alertDisplayNameFormat: Vectra AI Detect - Host {{SourceHostName}} reaches {{level}} severity
  alertDescriptionFormat: |
    The host {{SourceHostName}} has a Threat score of {{threat_score}} and a
    certainty of {{certainty_score}}    
  alertDynamicProperties:
  - value: vectra_URL
    alertProperty: AlertLink
  - value: DeviceProduct
    alertProperty: ProductName
  - value: DeviceVendor
    alertProperty: ProviderName
  - value: certainty_score
    alertProperty: ConfidenceScore
entityMappings:
- entityType: Host
  fieldMappings:
  - columnName: SourceHostName
    identifier: HostName
description: |
  'Create an incident when a Host is suspected to be compromised. 
  The higher the severity level is, the more immediate attention it requires as Vectra AI engine is more confident that this is a real threat. 
  Level of severity are: Low, Medium, High, Critical). Recommended configuration is to trigger an alert for at least High and Critical.'  
severity: Informational
queryFrequency: 5m
incidentConfiguration:
  groupingConfiguration:
    reopenClosedIncident: true
    matchingMethod: AllEntities
    lookbackDuration: 7d
    enabled: true
  createIncident: true
triggerThreshold: 0
relevantTechniques:
- T1003
- T1087
- T1021
- T1119
- T1071
- T1041
- T1499
status: Available
customDetails:
  ScoreDecrease: score_decreases
tactics:
- CredentialAccess
- Discovery
- LateralMovement
- Collection
- CommandAndControl
- Exfiltration
- Impact
name: Vectra AI Detect - Suspected Compromised Host
id: 60eb6cf0-3fa1-44c1-b1fe-220fbee23d63
query: |
  // Edit this variable to only keep the Severity level where an incident needs to be created (Defaults are: "High", "Critical" ). Possible values are: "Low", "Medium", "High", "Critical"
  let configured_level = dynamic(["High", "Critical"]);
  CommonSecurityLog
  | where DeviceVendor == "Vectra Networks"
  | where DeviceProduct == "X Series"
  | where DeviceEventClassID == "hsc"
  | project-rename threat_score = FlexNumber1
  | project-rename certainty_score = FlexNumber2
  | project-rename vectra_URL = DeviceCustomString4
  | project-rename detection_name = DeviceEventClassID
  | project-rename score_decreases = DeviceCustomString3
  | extend level = case( threat_score <  50 and certainty_score < 50, "Low",
                        threat_score < 50 and certainty_score >= 50 , "Medium", 
                        threat_score >= 50 and certainty_score <= 50, "High", 
                        threat_score >= 50 and certainty_score >= 50, "Critical",
                        "UNKNOWN")
  | extend Severity = case(level == "Info", "Informational",level == "Critical", "High", level)
  | where level in (configured_level) 
  //keep only the event with the highest threat score per Host
  | summarize arg_max(TimeGenerated, *) by SourceHostName
  | sort by TimeGenerated  
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CefAma
version: 1.0.9
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Vectra AI Detect/Analytic Rules/VectraDetect-Host-by-Severity.yaml
queryPeriod: 5m

ARM

{
  "$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/60eb6cf0-3fa1-44c1-b1fe-220fbee23d63')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/60eb6cf0-3fa1-44c1-b1fe-220fbee23d63')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "The host {{SourceHostName}} has a Threat score of {{threat_score}} and a\ncertainty of {{certainty_score}}\n",
          "alertDisplayNameFormat": "Vectra AI Detect - Host {{SourceHostName}} reaches {{level}} severity",
          "alertDynamicProperties": [
            {
              "alertProperty": "AlertLink",
              "value": "vectra_URL"
            },
            {
              "alertProperty": "ProductName",
              "value": "DeviceProduct"
            },
            {
              "alertProperty": "ProviderName",
              "value": "DeviceVendor"
            },
            {
              "alertProperty": "ConfidenceScore",
              "value": "certainty_score"
            }
          ],
          "alertSeverityColumnName": "Severity"
        },
        "alertRuleTemplateName": "60eb6cf0-3fa1-44c1-b1fe-220fbee23d63",
        "customDetails": {
          "ScoreDecrease": "score_decreases"
        },
        "description": "'Create an incident when a Host is suspected to be compromised. \nThe higher the severity level is, the more immediate attention it requires as Vectra AI engine is more confident that this is a real threat. \nLevel of severity are: Low, Medium, High, Critical). Recommended configuration is to trigger an alert for at least High and Critical.'\n",
        "displayName": "Vectra AI Detect - Suspected Compromised Host",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "SourceHostName",
                "identifier": "HostName"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "AlertPerResult"
        },
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "lookbackDuration": "P7D",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": true
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Vectra AI Detect/Analytic Rules/VectraDetect-Host-by-Severity.yaml",
        "query": "// Edit this variable to only keep the Severity level where an incident needs to be created (Defaults are: \"High\", \"Critical\" ). Possible values are: \"Low\", \"Medium\", \"High\", \"Critical\"\nlet configured_level = dynamic([\"High\", \"Critical\"]);\nCommonSecurityLog\n| where DeviceVendor == \"Vectra Networks\"\n| where DeviceProduct == \"X Series\"\n| where DeviceEventClassID == \"hsc\"\n| project-rename threat_score = FlexNumber1\n| project-rename certainty_score = FlexNumber2\n| project-rename vectra_URL = DeviceCustomString4\n| project-rename detection_name = DeviceEventClassID\n| project-rename score_decreases = DeviceCustomString3\n| extend level = case( threat_score <  50 and certainty_score < 50, \"Low\",\n                      threat_score < 50 and certainty_score >= 50 , \"Medium\", \n                      threat_score >= 50 and certainty_score <= 50, \"High\", \n                      threat_score >= 50 and certainty_score >= 50, \"Critical\",\n                      \"UNKNOWN\")\n| extend Severity = case(level == \"Info\", \"Informational\",level == \"Critical\", \"High\", level)\n| where level in (configured_level) \n//keep only the event with the highest threat score per Host\n| summarize arg_max(TimeGenerated, *) by SourceHostName\n| sort by TimeGenerated\n",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT5M",
        "severity": "Informational",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Collection",
          "CommandAndControl",
          "CredentialAccess",
          "Discovery",
          "Exfiltration",
          "Impact",
          "LateralMovement"
        ],
        "techniques": [
          "T1003",
          "T1021",
          "T1041",
          "T1071",
          "T1087",
          "T1119",
          "T1499"
        ],
        "templateVersion": "1.0.9",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}