Detection rules › Kusto

Box - New external user

Status
available
Severity
medium
Time window
1h
Source
github.com/Azure/Azure-Sentinel

'Detects when new user created with SourceLogin containing non-corporate domain.'

MITRE ATT&CK coverage

TacticTechniques
Initial Access
Persistence

Rule body

id: fd36ac88-cd92-4137-aa23-37a3648621fa
name: Box - New external user
description: |
  'Detects when new user created with SourceLogin containing non-corporate domain.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: BoxDataConnector
    dataTypes:
      - BoxEvents_CL
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - Persistence
relevantTechniques:
  - T1078
query: |
  BoxEvents
  | where EventType =~ 'NEW_USER'
  | extend corp_domain = extract(@'@(.*)', 1, SourceLogin)
  | extend new_domain = tolower(extract(@'@(.*)', 1, SourceLogin))
  | where corp_domain != new_domain
  | extend AccountCustomEntity = SourceLogin
  | extend IPCustomEntity = SrcIpAddr
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: AccountCustomEntity
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: source

BoxEvents

Stage 2: where

| where EventType =~ 'NEW_USER'

Stage 3: extend

| extend corp_domain = extract(@'@(.*)', 1, SourceLogin)

Stage 4: extend

| extend new_domain = tolower(extract(@'@(.*)', 1, SourceLogin))

Stage 5: where

| where corp_domain != new_domain

Stage 6: extend

| extend AccountCustomEntity = SourceLogin

Stage 7: extend

| extend IPCustomEntity = SrcIpAddr

Indicators

These rows show field, operator, and value matches.

Output fields

These fields are emitted when the rule matches.

FieldSource
corp_domainextend
new_domainextend
AccountCustomEntityextend
IPCustomEntityextend