Vectra AI Detect - Suspected Compromised Account

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Id	321f9dbd-64b7-4541-81dc-08cf7732ccb0
Rulename	Vectra AI Detect - Suspected Compromised Account
Description	Create an incident when an Account 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-Account-by-Severity.yaml
Version	1.0.9
Arm template	321f9dbd-64b7-4541-81dc-08cf7732ccb0.json

KQL

// Edit this variable to only keep the Severity level where an incident needs to be created.
//Level of severity are: Low, Medium, High, Critical). Recommended configuration is to trigger an alert for at least High and Critical.'
let configured_level = dynamic(["High", "Critical"]);
let upn_has_prefix = ":";
CommonSecurityLog
| where DeviceVendor == "Vectra Networks"
| where DeviceProduct == "X Series"
| where DeviceEventClassID == "asc"
| extend saccount = extract("saccount=(.+?);", 1, AdditionalExtensions)
| extend type = iff(saccount matches regex upn_has_prefix, tostring(split(saccount,":")[0]) ,"network" ) 
| extend upn = iff(saccount matches regex upn_has_prefix, tostring(split(saccount,":")[1]) , saccount )
| extend name = tostring(split(upn,"@")[0])
| extend upn_suffix = tostring(split(upn,"@")[1])
| 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(threat_score, *) by saccount
| sort by TimeGenerated

YAML

query: |
  // Edit this variable to only keep the Severity level where an incident needs to be created.
  //Level of severity are: Low, Medium, High, Critical). Recommended configuration is to trigger an alert for at least High and Critical.'
  let configured_level = dynamic(["High", "Critical"]);
  let upn_has_prefix = ":";
  CommonSecurityLog
  | where DeviceVendor == "Vectra Networks"
  | where DeviceProduct == "X Series"
  | where DeviceEventClassID == "asc"
  | extend saccount = extract("saccount=(.+?);", 1, AdditionalExtensions)
  | extend type = iff(saccount matches regex upn_has_prefix, tostring(split(saccount,":")[0]) ,"network" ) 
  | extend upn = iff(saccount matches regex upn_has_prefix, tostring(split(saccount,":")[1]) , saccount )
  | extend name = tostring(split(upn,"@")[0])
  | extend upn_suffix = tostring(split(upn,"@")[1])
  | 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(threat_score, *) by saccount
  | sort by TimeGenerated  
queryPeriod: 5m
queryFrequency: 5m
customDetails:
  ScoreDecrease: score_decreases
status: Available
id: 321f9dbd-64b7-4541-81dc-08cf7732ccb0
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: name
    identifier: Name
  - columnName: upn_suffix
    identifier: UPNSuffix
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    lookbackDuration: 7d
    reopenClosedIncident: true
    enabled: true
    matchingMethod: AllEntities
relevantTechniques:
- T1003
- T1087
- T1021
- T1119
- T1071
- T1041
- T1499
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Vectra AI Detect/Analytic Rules/VectraDetect-Account-by-Severity.yaml
requiredDataConnectors:
- connectorId: CefAma
  dataTypes:
  - CommonSecurityLog
eventGroupingSettings:
  aggregationKind: AlertPerResult
alertDetailsOverride:
  alertDynamicProperties:
  - alertProperty: AlertLink
    value: vectra_URL
  - alertProperty: ProductName
    value: DeviceProduct
  - alertProperty: ProviderName
    value: DeviceVendor
  - alertProperty: ConfidenceScore
    value: certainty_score
  alertSeverityColumnName: Severity
  alertDisplayNameFormat: Vectra AI Detect - Account {{saccount}} reaches {{level}} severity
  alertDescriptionFormat: |
    The account {{saccount}} has a threat score of {{threat_score}} and a
    certainty of {{certainty_score}}    
name: Vectra AI Detect - Suspected Compromised Account
description: |
  'Create an incident when an Account 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.'  
tactics:
- CredentialAccess
- Discovery
- LateralMovement
- Collection
- CommandAndControl
- Exfiltration
- Impact
severity: Informational
triggerThreshold: 0
version: 1.0.9
kind: Scheduled
triggerOperator: gt

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/321f9dbd-64b7-4541-81dc-08cf7732ccb0')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/321f9dbd-64b7-4541-81dc-08cf7732ccb0')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "The account {{saccount}} has a threat score of {{threat_score}} and a\ncertainty of {{certainty_score}}\n",
          "alertDisplayNameFormat": "Vectra AI Detect - Account {{saccount}} 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": "321f9dbd-64b7-4541-81dc-08cf7732ccb0",
        "customDetails": {
          "ScoreDecrease": "score_decreases"
        },
        "description": "'Create an incident when an Account 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 Account",
        "enabled": true,
        "entityMappings": [
          {
            "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 AI Detect/Analytic Rules/VectraDetect-Account-by-Severity.yaml",
        "query": "// Edit this variable to only keep the Severity level where an incident needs to be created.\n//Level of severity are: Low, Medium, High, Critical). Recommended configuration is to trigger an alert for at least High and Critical.'\nlet configured_level = dynamic([\"High\", \"Critical\"]);\nlet upn_has_prefix = \":\";\nCommonSecurityLog\n| where DeviceVendor == \"Vectra Networks\"\n| where DeviceProduct == \"X Series\"\n| where DeviceEventClassID == \"asc\"\n| extend saccount = extract(\"saccount=(.+?);\", 1, AdditionalExtensions)\n| extend type = iff(saccount matches regex upn_has_prefix, tostring(split(saccount,\":\")[0]) ,\"network\" ) \n| extend upn = iff(saccount matches regex upn_has_prefix, tostring(split(saccount,\":\")[1]) , saccount )\n| extend name = tostring(split(upn,\"@\")[0])\n| extend upn_suffix = tostring(split(upn,\"@\")[1])\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(threat_score, *) by saccount\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"
    }
  ]
}