Account created from non-approved sources

Severity: medium
Time window: 7d
Author: Microsoft Security Research
Source: github.com/Azure/Azure-Sentinel

This query looks for an account being created from a domain that is not regularly seen in a tenant. Attackers may attempt to add accounts from these sources as a means of establishing persistant access to an environment. Created accounts should be investigated to confirm expected creation. Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#short-lived-accounts

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1136.003` Create Account: Cloud Account

Event coverage

Provider	Event
Entra-AuditLogs	Add user

Rule body kusto

id: 99d589fa-7337-40d7-91a0-c96d0c4fa437
name: Account created from non-approved sources
description: |
  'This query looks for an account being created from a domain that is not regularly seen in a tenant.
    Attackers may attempt to add accounts from these sources as a means of establishing persistant access to an environment.
    Created accounts should be investigated to confirm expected creation.
    Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#short-lived-accounts'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - SigninLogs
      - AuditLogs
queryFrequency: 1d
queryPeriod: 7d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
relevantTechniques:
  - T1136.003
tags:
  - AADSecOpsGuide
query: |
  let core_domains = (SigninLogs
    | where TimeGenerated > ago(7d)
    | where ResultType == 0
    | extend domain = tolower(split(UserPrincipalName, "@")[1])
    | summarize by tostring(domain));
    let alternative_domains = (SigninLogs
    | where TimeGenerated > ago(7d)
    | where isnotempty(AlternateSignInName)
    | where ResultType == 0
    | extend domain = tolower(split(AlternateSignInName, "@")[1])
    | summarize by tostring(domain));
    AuditLogs
    | where TimeGenerated > ago(1d)
    | where OperationName =~ "Add User"
    | extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
    | extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
    | extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
    | extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
    | extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))
    | extend UserAdded = tostring(TargetResources[0].userPrincipalName)
    | extend UserAddedDomain = case(
    UserAdded has "#EXT#", tostring(split(tostring(split(UserAdded, "#EXT#")[0]), "_")[1]),
    UserAdded !has "#EXT#", tostring(split(UserAdded, "@")[1]),
    UserAdded)
    | where UserAddedDomain !in (core_domains) and UserAddedDomain !in (alternative_domains)
    | extend AddedByName = case(
    InitiatingUserPrincipalName has "#EXT#", tostring(split(tostring(split(InitiatingUserPrincipalName, "#EXT#")[0]), "_")[0]),
    InitiatingUserPrincipalName !has "#EXT#", tostring(split(InitiatingUserPrincipalName, "@")[0]),
    InitiatingUserPrincipalName)
    | extend AddedByUPNSuffix = case(
    InitiatingUserPrincipalName has "#EXT#", tostring(split(tostring(split(InitiatingUserPrincipalName, "#EXT#")[0]), "_")[1]),
    InitiatingUserPrincipalName !has "#EXT#", tostring(split(InitiatingUserPrincipalName, "@")[1]),
    InitiatingUserPrincipalName)
    | extend UserAddedName = case(
    UserAdded has "#EXT#", tostring(split(tostring(split(UserAdded, "#EXT#")[0]), "_")[0]),
    UserAdded !has "#EXT#", tostring(split(UserAdded, "@")[0]),
    UserAdded)
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: InitiatingAppName
      - identifier: AadUserId
        columnName: InitiatingAppServicePrincipalId
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: InitiatingUserPrincipalName
      - identifier: Name
        columnName: AddedByName
      - identifier: UPNSuffix
        columnName: AddedByUPNSuffix
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: InitiatingAadUserId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: InitiatingIpAddress
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserAdded
      - identifier: Name
        columnName: UserAddedName
      - identifier: UPNSuffix
        columnName: UserAddedDomain
version: 1.2.1
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]

Stages and Predicates

Let binding: `core_domains`

let core_domains = (SigninLogs
  | where TimeGenerated > ago(7d)
  | where ResultType == 0
  | extend domain = tolower(split(UserPrincipalName, "@")[1])
  | summarize by tostring(domain));

Let binding: `alternative_domains`

let alternative_domains = (SigninLogs
  | where TimeGenerated > ago(7d)
  | where isnotempty(AlternateSignInName)
  | where ResultType == 0
  | extend domain = tolower(split(AlternateSignInName, "@")[1])
  | summarize by tostring(domain));

Stage 1: `source`

AuditLogs

Stage 2: `where`

| where TimeGenerated > ago(1d)

Stage 3: `where`

| where OperationName =~ "Add User"

Stage 4: `extend` (7 consecutive steps)

| extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
| extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
| extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
| extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
| extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))
| extend UserAdded = tostring(TargetResources[0].userPrincipalName)
| extend UserAddedDomain = case(
  UserAdded has "#EXT#", tostring(split(tostring(split(UserAdded, "#EXT#")[0]), "_")[1]),
  UserAdded !has "#EXT#", tostring(split(UserAdded, "@")[1]),
  UserAdded)

Stage 5: `where`

| where UserAddedDomain !in (core_domains) and UserAddedDomain !in (alternative_domains)

References alternative_domains, core_domains (defined above).

Stage 6: `extend` (3 consecutive steps)

| extend AddedByName = case(
  InitiatingUserPrincipalName has "#EXT#", tostring(split(tostring(split(InitiatingUserPrincipalName, "#EXT#")[0]), "_")[0]),
  InitiatingUserPrincipalName !has "#EXT#", tostring(split(InitiatingUserPrincipalName, "@")[0]),
  InitiatingUserPrincipalName)
| extend AddedByUPNSuffix = case(
  InitiatingUserPrincipalName has "#EXT#", tostring(split(tostring(split(InitiatingUserPrincipalName, "#EXT#")[0]), "_")[1]),
  InitiatingUserPrincipalName !has "#EXT#", tostring(split(InitiatingUserPrincipalName, "@")[1]),
  InitiatingUserPrincipalName)
| extend UserAddedName = case(
  UserAdded has "#EXT#", tostring(split(tostring(split(UserAdded, "#EXT#")[0]), "_")[0]),
  UserAdded !has "#EXT#", tostring(split(UserAdded, "@")[0]),
  UserAdded)

AddedByName =

ifInitiatingUserPrincipalName has "#EXT#"tostring(split(tostring(split(InitiatingUserPrincipalName, "#EXT#")[0]), "_")[0])

elifnot (InitiatingUserPrincipalName has "#EXT#")tostring(split(InitiatingUserPrincipalName, "@")[0])

elseInitiatingUserPrincipalName

Exclusions

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

Field	Kind	Excluded values
`UserAddedDomain`	eq	`alternative_domains`
`UserAddedDomain`	eq	`core_domains`

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.

Field	Kind	Values
`OperationName`	eq	`Add User`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`InitiatingAppName`	`extend`
`InitiatingAppServicePrincipalId`	`extend`
`InitiatingUserPrincipalName`	`extend`
`InitiatingAadUserId`	`extend`
`InitiatingIpAddress`	`extend`
`UserAdded`	`extend`
`UserAddedDomain`	`extend`
`AddedByName`	`extend`
`AddedByUPNSuffix`	`extend`
`UserAddedName`	`extend`

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`f`	Follow link (`Shift` = new tab)
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`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Account created from non-approved sources

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: `core_domains`

Let binding: `alternative_domains`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend` (7 consecutive steps)

Stage 5: `where`

Stage 6: `extend` (3 consecutive steps)

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Account created from non-approved sources

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: core_domains

Let binding: alternative_domains

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend (7 consecutive steps)

Stage 5: where

Stage 6: extend (3 consecutive steps)

Exclusions

Indicators

Output fields

Let binding: `core_domains`

Let binding: `alternative_domains`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend` (7 consecutive steps)

Stage 5: `where`

Stage 6: `extend` (3 consecutive steps)