Detection rules › Kusto

Suspicious modification of Global Administrator user properties

Severity
medium
Time window
14d
Group by
AccountObjectId
Author
Microsoft Security Research
Source
github.com/Azure/Azure-Sentinel

This query will detect if user properties of Global Administrator are updated by an existing user. Usually only user administrator or other global administrator can update such properties. Investigate if such user change is an attempt to elevate an existing low privileged identity or rogue administrator activity

MITRE ATT&CK coverage

TacticTechniques
Privilege Escalation

Telemetry coverage

Rules detecting the same action

These rules filter on the same operation.

Rule body

id: 48602a24-67cf-4362-b258-3f4249e55def
name: Suspicious modification of Global Administrator user properties
description: |
  'This query will detect if user properties of Global Administrator are updated by an existing user. Usually only user administrator or other global administrator can update such properties.
  Investigate if such user change is an attempt to elevate an existing low privileged identity or rogue administrator activity'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
  - connectorId: BehaviorAnalytics
    dataTypes:
      - IdentityInfo
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - PrivilegeEscalation
relevantTechniques:
  - T1078.004
query: |
  let query_frequency = 1h;
  let query_period = 14d;
  IdentityInfo
  | where TimeGenerated > ago(query_period)
  | where set_has_element(AssignedRoles, "Global Administrator")
  | distinct AccountUPN, AccountObjectId
  | join kind=inner (
      AuditLogs
      | where TimeGenerated > ago(query_frequency)
      | where OperationName=~ "Update user" and Result =~ "success"
      // | where isnotempty(InitiatedBy["user"])
      | mv-expand TargetResource = TargetResources
      | where TargetResource["type"] == "User"
      | extend AccountObjectId = tostring(TargetResource["id"])
      | where tostring(TargetResource["modifiedProperties"]) != "[]"
      | mv-apply modifiedProperty = TargetResource["modifiedProperties"] on (
          summarize modifiedProperties = make_bag(
              bag_pack(tostring(modifiedProperty["displayName"]),
                  bag_pack("oldValue", trim(@'[\"\s]+', tostring(modifiedProperty["oldValue"])),
                      "newValue", trim(@'[\"\s]+', tostring(modifiedProperty["newValue"])))))
      )
      | where not(tostring(modifiedProperties["Included Updated Properties"]["newValue"]) in ("LastDirSyncTime", ""))
      | where not(tostring(modifiedProperties["Included Updated Properties"]["newValue"]) == "StrongAuthenticationPhoneAppDetail" and isnotempty(modifiedProperties["StrongAuthenticationPhoneAppDetail"]) and tostring(array_sort_asc(extract_all(@'\"Id\"\:\"([^\"]+)\"', tostring(modifiedProperties["StrongAuthenticationPhoneAppDetail"]["newValue"])))) == tostring(array_sort_asc(extract_all(@'\"Id\"\:\"([^\"]+)\"', tostring(modifiedProperties["StrongAuthenticationPhoneAppDetail"]["oldValue"])))))
      | extend
          Initiator = iif(isnotempty(InitiatedBy["app"]), tostring(InitiatedBy["app"]["displayName"]), tostring(InitiatedBy["user"]["userPrincipalName"])),
          InitiatorId = iif(isnotempty(InitiatedBy["app"]), tostring(InitiatedBy["app"]["servicePrincipalId"]), tostring(InitiatedBy["user"]["id"])),
          IPAddress = tostring(InitiatedBy[tostring(bag_keys(InitiatedBy)[0])]["ipAddress"])
  ) on AccountObjectId
  | project TimeGenerated, Category, Identity, Initiator, IPAddress, OperationName, Result, AccountUPN, InitiatedBy, AdditionalDetails, TargetResources, AccountObjectId, InitiatorId, CorrelationId
  | extend
      InitiatorName = tostring(split(Initiator, "@")[0]),
      InitiatorUPNSuffix = tostring(split(Initiator, "@")[1]),
      AccountName = tostring(split(AccountUPN, "@")[0]),
      AccountUPNSuffix = tostring(split(AccountUPN, "@")[1])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: Initiator
      - identifier: Name
        columnName: InitiatorName
      - identifier: UPNSuffix
        columnName: InitiatorUPNSuffix
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: AccountUPN
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPAddress
version: 1.0.4
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]

Stages and Predicates

Parameters

let query_frequency = 1h;
let query_period = 14d;

Stage 1: source

IdentityInfo

Stage 2: where

| where TimeGenerated > ago(query_period)

Stage 3: where

| where set_has_element(AssignedRoles, "Global Administrator")

Stage 4: distinct

| distinct AccountUPN, AccountObjectId

Stage 5: join

| join kind=inner (
    AuditLogs
    | where TimeGenerated > ago(query_frequency)
    | where OperationName=~ "Update user" and Result =~ "success"
    | mv-expand TargetResource = TargetResources
    | where TargetResource["type"] == "User"
    | extend AccountObjectId = tostring(TargetResource["id"])
    | where tostring(TargetResource["modifiedProperties"]) != "[]"
    | mv-apply modifiedProperty = TargetResource["modifiedProperties"] on (
        summarize modifiedProperties = make_bag(
            bag_pack(tostring(modifiedProperty["displayName"]),
                bag_pack("oldValue", trim(@'[\"\s]+', tostring(modifiedProperty["oldValue"])),
                    "newValue", trim(@'[\"\s]+', tostring(modifiedProperty["newValue"])))))
    )
    | where not(tostring(modifiedProperties["Included Updated Properties"]["newValue"]) in ("LastDirSyncTime", ""))
    | where not(tostring(modifiedProperties["Included Updated Properties"]["newValue"]) == "StrongAuthenticationPhoneAppDetail" and isnotempty(modifiedProperties["StrongAuthenticationPhoneAppDetail"]) and tostring(array_sort_asc(extract_all(@'\"Id\"\:\"([^\"]+)\"', tostring(modifiedProperties["StrongAuthenticationPhoneAppDetail"]["newValue"])))) == tostring(array_sort_asc(extract_all(@'\"Id\"\:\"([^\"]+)\"', tostring(modifiedProperties["StrongAuthenticationPhoneAppDetail"]["oldValue"])))))
    | extend
        Initiator = iif(isnotempty(InitiatedBy["app"]), tostring(InitiatedBy["app"]["displayName"]), tostring(InitiatedBy["user"]["userPrincipalName"])),
        InitiatorId = iif(isnotempty(InitiatedBy["app"]), tostring(InitiatedBy["app"]["servicePrincipalId"]), tostring(InitiatedBy["user"]["id"])),
        IPAddress = tostring(InitiatedBy[tostring(bag_keys(InitiatedBy)[0])]["ipAddress"])
) on AccountObjectId

Stage 6: project

| project TimeGenerated, Category, Identity, Initiator, IPAddress, OperationName, Result, AccountUPN, InitiatedBy, AdditionalDetails, TargetResources, AccountObjectId, InitiatorId, CorrelationId

Stage 7: extend

| extend
    InitiatorName = tostring(split(Initiator, "@")[0]),
    InitiatorUPNSuffix = tostring(split(Initiator, "@")[1]),
    AccountName = tostring(split(AccountUPN, "@")[0]),
    AccountUPNSuffix = tostring(split(AccountUPN, "@")[1])

Stage 8: summarize aggregation inside the mv-apply branch

summarize

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
StrongAuthenticationPhoneAppDetailis_not_null(no value, null check)excludes:StrongAuthenticationPhoneAppDetail
newValueeqStrongAuthenticationPhoneAppDetailexcludes:newValue field:"newValue" value:"StrongAuthenticationPhoneAppDetail"
newValueinLastDirSyncTimeexcludes:newValue field:"newValue" value:"LastDirSyncTime"

Indicators

These rows show field, operator, and value matches.