Netskope - Heavy Personal Cloud Storage Usage (Shadow IT)

Status: available
Severity: medium
Time window: 1h
Group by: CsUsername, XCCountry, XCDevice, XCsApp, XCsAppCategory, XCsAppInstanceName, XCsAppTags
Source: github.com/Azure/Azure-Sentinel

Detects heavy usage of personal cloud storage applications like personal Dropbox, Google Drive, OneDrive personal, etc. Indicates potential Shadow IT or data leakage risk.

MITRE ATT&CK coverage

Tactic	Techniques
Collection	`T1530` Data from Cloud Storage
Exfiltration	`T1567` Exfiltration Over Web Service

Rule body

id: 272f9bca-5fd0-4413-b494-03b2d9f0bb9b
name: Netskope - Heavy Personal Cloud Storage Usage (Shadow IT)
description: |
  Detects heavy usage of personal cloud storage applications like personal Dropbox, Google Drive, OneDrive personal, etc. Indicates potential Shadow IT or data leakage risk.
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: NetskopeWebTxConnector
    dataTypes:
      - NetskopeWebTransactions_CL
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Exfiltration
  - Collection
relevantTechniques:
  - T1567
  - T1530
query: |
  let heavyUsageThresholdMB = 500;
  NetskopeWebTransactions_CL
  | where TimeGenerated > ago(1h)
  | where isnotempty(CsUsername) and isnotempty(XCsApp)
  | where XCsApp has_any ('Dropbox', 'Google Drive', 'OneDrive', 'Box', 'iCloud', 'pCloud', 'MEGA', 'MediaFire', 'WeTransfer')
  | where XCsAppInstanceTag contains 'Personal' 
      or XCsAppInstanceName contains 'Personal'
      or XCsAppTags contains 'Unsanctioned'
      or not(XCsAppTags contains 'Enterprise')
  | summarize 
      TotalBytes = sum(Bytes),
      UploadBytes = sum(CsBytes),
      DownloadBytes = sum(ScBytes),
      FileCount = dcount(XCsAppObjectName),
      Files = make_set(XCsAppObjectName, 10),
      Activities = make_set(XCsAppActivity),
      EventCount = count()
      by CsUsername, XCsApp, XCsAppCategory, XCsAppInstanceName, XCsAppTags, XCDevice, XCCountry
  | extend 
      TotalMB = round(TotalBytes / 1048576.0, 2),
      UploadMB = round(UploadBytes / 1048576.0, 2),
      DownloadMB = round(DownloadBytes / 1048576.0, 2)
  | where TotalMB > heavyUsageThresholdMB or FileCount > 50
  | project 
      TimeGenerated = now(),
      User = CsUsername,
      CloudApplication = XCsApp,
      AppCategory = XCsAppCategory,
      AppInstance = XCsAppInstanceName,
      AppTags = XCsAppTags,
      TotalDataMB = TotalMB,
      UploadMB,
      DownloadMB,
      FileCount,
      Files,
      Activities,
      Device = XCDevice,
      Country = XCCountry,
      EventCount
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: User
  - entityType: CloudApplication
    fieldMappings:
      - identifier: Name
        columnName: CloudApplication
version: 1.0.0
kind: Scheduled

Stages and Predicates

Parameters

let heavyUsageThresholdMB = 500;

Stage 1: `source`

NetskopeWebTransactions_CL

Stage 2: `where`

| where TimeGenerated > ago(1h)

Stage 3: `where`

| where isnotempty(CsUsername) and isnotempty(XCsApp)

Stage 4: `where`

| where XCsApp has_any ('Dropbox', 'Google Drive', 'OneDrive', 'Box', 'iCloud', 'pCloud', 'MEGA', 'MediaFire', 'WeTransfer')

Stage 5: `where`

| where XCsAppInstanceTag contains 'Personal' 
    or XCsAppInstanceName contains 'Personal'
    or XCsAppTags contains 'Unsanctioned'
    or not(XCsAppTags contains 'Enterprise')

Stage 6: `summarize`

| summarize 
    TotalBytes = sum(Bytes),
    UploadBytes = sum(CsBytes),
    DownloadBytes = sum(ScBytes),
    FileCount = dcount(XCsAppObjectName),
    Files = make_set(XCsAppObjectName, 10),
    Activities = make_set(XCsAppActivity),
    EventCount = count()
    by CsUsername, XCsApp, XCsAppCategory, XCsAppInstanceName, XCsAppTags, XCDevice, XCCountry

Stage 7: `extend`

| extend 
    TotalMB = round(TotalBytes / 1048576.0, 2),
    UploadMB = round(UploadBytes / 1048576.0, 2),
    DownloadMB = round(DownloadBytes / 1048576.0, 2)

Stage 8: `where`

| where TotalMB > heavyUsageThresholdMB or FileCount > 50

Stage 9: `project`

| project 
    TimeGenerated = now(),
    User = CsUsername,
    CloudApplication = XCsApp,
    AppCategory = XCsAppCategory,
    AppInstance = XCsAppInstanceName,
    AppTags = XCsAppTags,
    TotalDataMB = TotalMB,
    UploadMB,
    DownloadMB,
    FileCount,
    Files,
    Activities,
    Device = XCDevice,
    Country = XCCountry,
    EventCount

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CsUsername`	is_not_null	(no value, null check)	`field:"CsUsername" kind:is_not_null`
`FileCount`	gt	`50`	`field:"FileCount" kind:gt value:"50"`
`TotalMB`	gt	`500`	`field:"TotalMB" kind:gt value:"500"`
`XCsApp`	is_not_null	(no value, null check)	`field:"XCsApp" kind:is_not_null`
`XCsApp`	match	`Box` transforms: `term` `Dropbox` transforms: `term` `Google Drive` transforms: `term` `MEGA` transforms: `term` `MediaFire` transforms: `term` `OneDrive` transforms: `term` `WeTransfer` transforms: `term` `iCloud` transforms: `term` `pCloud` transforms: `term`	`field:"XCsApp" kind:match`
`XCsAppInstanceName`	contains	`Personal`	`field:"XCsAppInstanceName" kind:contains value:"Personal"`
`XCsAppInstanceTag`	contains	`Personal`	`field:"XCsAppInstanceTag" kind:contains value:"Personal"`
`XCsAppTags`	contains	`Unsanctioned`	`field:"XCsAppTags" kind:contains value:"Unsanctioned"`

Output fields

These fields are emitted when the rule matches.

Field	Source
`Activities`	`project`
`AppCategory`	`project`
`AppInstance`	`project`
`AppTags`	`project`
`CloudApplication`	`project`
`Country`	`project`
`Device`	`project`
`DownloadMB`	`project`
`EventCount`	`project`
`FileCount`	`project`
`Files`	`project`
`TimeGenerated`	`project`
`TotalDataMB`	`project`
`UploadMB`	`project`
`User`	`project`

Netskope - Heavy Personal Cloud Storage Usage (Shadow IT)

MITRE ATT&CK coverage

Rule body

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: where

Stage 6: summarize

Stage 7: extend

Stage 8: where

Stage 9: project