Vectra AI Detect - Detections with High Severity | Microsoft Sentinel Analytic Rules

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Id	39e48890-2c02-487e-aa9e-3ba494061798
Rulename	Vectra AI Detect - Detections with High Severity
Description	Create an incident for high severity malicious behavior detected by Vectra AI (Threat score superior to 7.0). The Severity is a mapping with the Threat score assigned to a detection. It ranges between 0 and 10. The severity_threshold variable can be adjusted as desired.'
Severity	High
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%20AI%20Detect/Analytic%20Rules/VectraDetect-HighSeverityDetection-by-Tactics.yaml
Version	1.1.0
Arm template	39e48890-2c02-487e-aa9e-3ba494061798.json

KQL

// Edit this variable to only keep the tactics where an incident needs to be created (Defaults are: "COMMAND & CONTROL", "BOTNET ACTIVITY", "EXFILTRATION", "LATERAL MOVEMENT", "RECONNAISSANCE")   
let configured_tactics = dynamic(["COMMAND & CONTROL", "BOTNET ACTIVITY", "EXFILTRATION", "LATERAL MOVEMENT", "RECONNAISSANCE"]);
//default threshold is 7 (meaning a threat score of 70)
let severity_threshold = 7.0;
//Map by default to High Severity in Sentinel
let Severity = "High";
CommonSecurityLog
| where DeviceVendor == "Vectra Networks"
| where DeviceProduct == "X Series"
| where DeviceEventClassID != "campaigns" and DeviceEventClassID != "hsc" and DeviceEventClassID != "audit" and DeviceEventClassID != "health" and DeviceEventClassID != "asc"
| extend Category = coalesce(
                          column_ifexists("DeviceEventCategory", ""), 
                          extract("cat=(.+?)(;|$)", 1, AdditionalExtensions), 
                          ""
                      )
| project-rename threat_score = FlexNumber1
| project-rename certainty_score = FlexNumber2
| project-rename vectra_URL = DeviceCustomString4
| project-rename detection_name = DeviceEventClassID
| where todecimal(LogSeverity) >= severity_threshold
| extend Tactic = case( Category == "COMMAND & CONTROL", "CommandAndControl",
                        Category == "BOTNET ACTIVITY" , "Impact",
                        Category == "EXFILTRATION", "Exfiltration",
                        Category == "LATERAL MOVEMENT", "LateralMovement",
                        Category == "RECONNAISSANCE", "Discovery",
                        "UNKNOWN")
| extend level = case(threat_score == 0 and certainty_score == 0, "Info",
    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)
| extend account = extract("account=(.+?);", 1, AdditionalExtensions)
| extend upn = iff(account matches regex ":", tostring(split(account,":")[1]) ,tostring(split(account,":")[0]))
| extend name = tostring(split(upn, "@")[0])
| extend upn_suffix = tostring(split(upn, "@")[1])
| extend source_entity = case( isnotempty(upn), upn,
                               isnotempty(SourceHostName), SourceHostName,
                               "UNKNWON") 
| where Category in (configured_tactics) 
| summarize arg_max(threat_score, *) by source_entity, Activity
| sort by TimeGenerated

YAML

requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CefAma
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Vectra%20AI%20Detect/Analytic%20Rules/VectraDetect-HighSeverityDetection-by-Tactics.yaml
version: 1.1.0
status: Available
alertDetailsOverride:
  alertDescriptionFormat: Source entity is {{source_entity}} and category is {{Category}}. Threat score is {{threat_score}}.
  alertDynamicProperties:
  - alertProperty: AlertLink
    value: vectra_URL
  - alertProperty: ProductName
    value: DeviceProduct
  - alertProperty: ProviderName
    value: DeviceVendor
  - alertProperty: ConfidenceScore
    value: certainty_score
  alertDisplayNameFormat: Vectra AI Detect - {{Activity}} detected
  alertSeverityColumnName: Severity
relevantTechniques:
- T1003
- T1087
- T1021
- T1119
- T1071
- T1041
- T1499
incidentConfiguration:
  groupingConfiguration:
    reopenClosedIncident: true
    matchingMethod: AllEntities
    enabled: true
    lookbackDuration: 7d
  createIncident: true
customDetails:
  AttackType: Activity
  AttackCategory: Category
query: |
  // Edit this variable to only keep the tactics where an incident needs to be created (Defaults are: "COMMAND & CONTROL", "BOTNET ACTIVITY", "EXFILTRATION", "LATERAL MOVEMENT", "RECONNAISSANCE")   
  let configured_tactics = dynamic(["COMMAND & CONTROL", "BOTNET ACTIVITY", "EXFILTRATION", "LATERAL MOVEMENT", "RECONNAISSANCE"]);
  //default threshold is 7 (meaning a threat score of 70)
  let severity_threshold = 7.0;
  //Map by default to High Severity in Sentinel
  let Severity = "High";
  CommonSecurityLog
  | where DeviceVendor == "Vectra Networks"
  | where DeviceProduct == "X Series"
  | where DeviceEventClassID != "campaigns" and DeviceEventClassID != "hsc" and DeviceEventClassID != "audit" and DeviceEventClassID != "health" and DeviceEventClassID != "asc"
  | extend Category = coalesce(
                            column_ifexists("DeviceEventCategory", ""), 
                            extract("cat=(.+?)(;|$)", 1, AdditionalExtensions), 
                            ""
                        )
  | project-rename threat_score = FlexNumber1
  | project-rename certainty_score = FlexNumber2
  | project-rename vectra_URL = DeviceCustomString4
  | project-rename detection_name = DeviceEventClassID
  | where todecimal(LogSeverity) >= severity_threshold
  | extend Tactic = case( Category == "COMMAND & CONTROL", "CommandAndControl",
                          Category == "BOTNET ACTIVITY" , "Impact",
                          Category == "EXFILTRATION", "Exfiltration",
                          Category == "LATERAL MOVEMENT", "LateralMovement",
                          Category == "RECONNAISSANCE", "Discovery",
                          "UNKNOWN")
  | extend level = case(threat_score == 0 and certainty_score == 0, "Info",
      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)
  | extend account = extract("account=(.+?);", 1, AdditionalExtensions)
  | extend upn = iff(account matches regex ":", tostring(split(account,":")[1]) ,tostring(split(account,":")[0]))
  | extend name = tostring(split(upn, "@")[0])
  | extend upn_suffix = tostring(split(upn, "@")[1])
  | extend source_entity = case( isnotempty(upn), upn,
                                 isnotempty(SourceHostName), SourceHostName,
                                 "UNKNWON") 
  | where Category in (configured_tactics) 
  | summarize arg_max(threat_score, *) by source_entity, Activity
  | sort by TimeGenerated
tactics:
- CredentialAccess
- Discovery
- LateralMovement
- Collection
- CommandAndControl
- Exfiltration
- Impact
queryFrequency: 5m
id: 39e48890-2c02-487e-aa9e-3ba494061798
triggerThreshold: 0
triggerOperator: gt
name: Vectra AI Detect - Detections with High Severity
queryPeriod: 5m
severity: High
entityMappings:
- fieldMappings:
  - columnName: SourceHostName
    identifier: HostName
  entityType: Host
- fieldMappings:
  - columnName: name
    identifier: Name
  - columnName: upn_suffix
    identifier: UPNSuffix
  entityType: Account
kind: Scheduled
eventGroupingSettings:
  aggregationKind: AlertPerResult
description: |
  'Create an incident for high severity malicious behavior detected by Vectra AI (Threat score superior to 7.0). 
  The Severity is a mapping with the Threat score assigned to a detection. It ranges between 0 and 10. 
  The severity_threshold variable can be adjusted as desired.'

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/39e48890-2c02-487e-aa9e-3ba494061798')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/39e48890-2c02-487e-aa9e-3ba494061798')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "Source entity is {{source_entity}} and category is {{Category}}. Threat score is {{threat_score}}.",
          "alertDisplayNameFormat": "Vectra AI Detect - {{Activity}} detected",
          "alertDynamicProperties": [
            {
              "alertProperty": "AlertLink",
              "value": "vectra_URL"
            },
            {
              "alertProperty": "ProductName",
              "value": "DeviceProduct"
            },
            {
              "alertProperty": "ProviderName",
              "value": "DeviceVendor"
            },
            {
              "alertProperty": "ConfidenceScore",
              "value": "certainty_score"
            }
          ],
          "alertSeverityColumnName": "Severity"
        },
        "alertRuleTemplateName": "39e48890-2c02-487e-aa9e-3ba494061798",
        "customDetails": {
          "AttackCategory": "Category",
          "AttackType": "Activity"
        },
        "description": "'Create an incident for high severity malicious behavior detected by Vectra AI (Threat score superior to 7.0). \nThe Severity is a mapping with the Threat score assigned to a detection. It ranges between 0 and 10. \nThe severity_threshold variable can be adjusted as desired.' \n",
        "displayName": "Vectra AI Detect - Detections with High Severity",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "SourceHostName",
                "identifier": "HostName"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "name",
                "identifier": "Name"
              },
              {
                "columnName": "upn_suffix",
                "identifier": "UPNSuffix"
              }
            ]
          }
        ],
        "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%20AI%20Detect/Analytic%20Rules/VectraDetect-HighSeverityDetection-by-Tactics.yaml",
        "query": "// Edit this variable to only keep the tactics where an incident needs to be created (Defaults are: \"COMMAND & CONTROL\", \"BOTNET ACTIVITY\", \"EXFILTRATION\", \"LATERAL MOVEMENT\", \"RECONNAISSANCE\")   \nlet configured_tactics = dynamic([\"COMMAND & CONTROL\", \"BOTNET ACTIVITY\", \"EXFILTRATION\", \"LATERAL MOVEMENT\", \"RECONNAISSANCE\"]);\n//default threshold is 7 (meaning a threat score of 70)\nlet severity_threshold = 7.0;\n//Map by default to High Severity in Sentinel\nlet Severity = \"High\";\nCommonSecurityLog\n| where DeviceVendor == \"Vectra Networks\"\n| where DeviceProduct == \"X Series\"\n| where DeviceEventClassID != \"campaigns\" and DeviceEventClassID != \"hsc\" and DeviceEventClassID != \"audit\" and DeviceEventClassID != \"health\" and DeviceEventClassID != \"asc\"\n| extend Category = coalesce(\n                          column_ifexists(\"DeviceEventCategory\", \"\"), \n                          extract(\"cat=(.+?)(;|$)\", 1, AdditionalExtensions), \n                          \"\"\n                      )\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| where todecimal(LogSeverity) >= severity_threshold\n| extend Tactic = case( Category == \"COMMAND & CONTROL\", \"CommandAndControl\",\n                        Category == \"BOTNET ACTIVITY\" , \"Impact\",\n                        Category == \"EXFILTRATION\", \"Exfiltration\",\n                        Category == \"LATERAL MOVEMENT\", \"LateralMovement\",\n                        Category == \"RECONNAISSANCE\", \"Discovery\",\n                        \"UNKNOWN\")\n| extend level = case(threat_score == 0 and certainty_score == 0, \"Info\",\n    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| extend account = extract(\"account=(.+?);\", 1, AdditionalExtensions)\n| extend upn = iff(account matches regex \":\", tostring(split(account,\":\")[1]) ,tostring(split(account,\":\")[0]))\n| extend name = tostring(split(upn, \"@\")[0])\n| extend upn_suffix = tostring(split(upn, \"@\")[1])\n| extend source_entity = case( isnotempty(upn), upn,\n                               isnotempty(SourceHostName), SourceHostName,\n                               \"UNKNWON\") \n| where Category in (configured_tactics) \n| summarize arg_max(threat_score, *) by source_entity, Activity\n| sort by TimeGenerated\n",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT5M",
        "severity": "High",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Collection",
          "CommandAndControl",
          "CredentialAccess",
          "Discovery",
          "Exfiltration",
          "Impact",
          "LateralMovement"
        ],
        "techniques": [
          "T1003",
          "T1021",
          "T1041",
          "T1071",
          "T1087",
          "T1119",
          "T1499"
        ],
        "templateVersion": "1.1.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}