Vectra Hosts Behaviors

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Id	33e3b6da-2660-4cd7-9032-11be76db88d2
Rulename	Vectra Host’s Behaviors
Description	This analytic rule is looking for new attacker behaviors observed by the Vectra Platform. This rule is focused on host’s detections.
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-Detections.yaml
Version	1.0.5
Arm template	33e3b6da-2660-4cd7-9032-11be76db88d2.json

KQL

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
| project-rename triaged = DeviceCustomString5
| where triaged != "True" and AdditionalExtensions !has "account"
| extend source_entity = case(isnotempty(SourceHostName), SourceHostName,
    "UNKNWON")
| 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)
| summarize arg_max(threat_score, *) by source_entity, Activity
| sort by TimeGenerated

YAML

queryPeriod: 5m
severity: Informational
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Vectra AI Detect/Analytic Rules/VectraDetect-Host-Detections.yaml
version: 1.0.5
status: Available
description: |
    'This analytic rule is looking for new attacker behaviors observed by the Vectra Platform. This rule is focused on host's detections.'
kind: Scheduled
entityMappings:
- fieldMappings:
  - identifier: HostName
    columnName: SourceHostName
  entityType: Host
customDetails:
  AttackType: Activity
  AttackCategory: Category
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CefAma
name: Vectra Host's Behaviors
triggerThreshold: 0
query: |
  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
  | project-rename triaged = DeviceCustomString5
  | where triaged != "True" and AdditionalExtensions !has "account"
  | extend source_entity = case(isnotempty(SourceHostName), SourceHostName,
      "UNKNWON")
  | 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)
  | summarize arg_max(threat_score, *) by source_entity, Activity
  | sort by TimeGenerated  
relevantTechniques:
- T1003
- T1087
- T1021
- T1119
- T1071
- T1041
- T1499
triggerOperator: gt
tactics:
- CredentialAccess
- Discovery
- LateralMovement
- Collection
- CommandAndControl
- Exfiltration
- Impact
id: 33e3b6da-2660-4cd7-9032-11be76db88d2
eventGroupingSettings:
  aggregationKind: AlertPerResult
alertDetailsOverride:
  alertDescriptionFormat: |
        Entity is a host. Category is {{Category}}. Threat score is {{threat_score}} and certainty score is {{certainty_score}}.
  alertDynamicProperties:
  - value: vectra_URL
    alertProperty: AlertLink
  - value: DeviceProduct
    alertProperty: ProductName
  - value: DeviceVendor
    alertProperty: ProviderName
  - value: certainty_score
    alertProperty: ConfidenceScore
  alertDisplayNameFormat: Vectra AI - {{Activity}} Detected
  alertSeverityColumnName: Severity
queryFrequency: 5m

ARM