Detection rules › Kusto

Suspicious modification of Global Administrator user properties

Severity
medium
Time window
14d
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 EscalationT1078.004 Valid Accounts: Cloud Accounts

Event coverage

Rule body kusto

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

summarize

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
StrongAuthenticationPhoneAppDetailis_not_null(no value, null check)
newValueeqStrongAuthenticationPhoneAppDetail
newValueinLastDirSyncTime

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
AssignedRolesin
  • Global Administrator transforms: set_has_element
OperationNameeq
  • Update user
Resulteq
  • success
modifiedPropertiesne
  • [] transforms: tostring, cased
typeeq
  • User transforms: cased