Privileged User Logon from new ASN

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

'Detects a successful logon by a privileged account from an ASN not logged in from in the last 14 days. Monitor these logons to ensure they are legitimate and identify if there are any similar sign ins.'

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1078.004` Valid Accounts: Cloud Accounts

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

Anomalous sign-in location by user account and authenticating application (Kusto)
Anomalous Single Factor Signin (Kusto)
Authentications of Privileged Accounts Outside of Expected Controls (Kusto)
Azure Many Failed SignIns (Panther)
Azure Portal sign in from another Azure Tenant (Kusto)
Azure Service Principal Sign-In Followed by Arc Cluster Credential Access (Elastic)
Azure SignIn via Legacy Authentication Protocol (Panther)
Detect non-admin requesting token for admin applications (Kusto)

Rule body kusto

id: 55073036-bb86-47d3-a85a-b113ac3d9396
name: Privileged User Logon from new ASN
description: |
  'Detects a successful logon by a privileged account from an ASN not logged in from in the last 14 days.
    Monitor these logons to ensure they are legitimate and identify if there are any similar sign ins.'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - SigninLogs
  - connectorId: BehaviorAnalytics
    dataTypes:
      - BehaviorAnalytics
  - connectorId: BehaviorAnalytics
    dataTypes:
      - IdentityInfo
queryFrequency: 1d
queryPeriod: 7d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1078.004
tags:
  - AADSecOpsGuide
query: |
  let admins=(IdentityInfo
    | where AssignedRoles contains "admin" or GroupMembership has "Admin"
    | summarize by tolower(AccountUPN));
    let known_asns = (
    SigninLogs
    | where TimeGenerated between(ago(14d)..ago(1d))
    | where ResultType == 0
    | summarize by AutonomousSystemNumber);
    SigninLogs
    | where TimeGenerated > ago(1d)
    | where ResultType == 0
    | where tolower(UserPrincipalName) in (admins)
    | where AutonomousSystemNumber !in (known_asns)
    | project-reorder TimeGenerated, UserPrincipalName, UserAgent, IPAddress, AutonomousSystemNumber
    | extend AccountName = tostring(split(UserPrincipalName, "@")[0]), AccountUPNSuffix = tostring(split(UserPrincipalName, "@")[1])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserPrincipalName
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPAddress
version: 1.0.6
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Identity", "Security - Others" ]

Stages and Predicates

Let binding: `admins`

let admins = (IdentityInfo
  | where AssignedRoles contains "admin" or GroupMembership has "Admin"
  | summarize by tolower(AccountUPN));

Let binding: `known_asns`

let known_asns = (
  SigninLogs
  | where TimeGenerated between(ago(14d)..ago(1d))
  | where ResultType == 0
  | summarize by AutonomousSystemNumber);

Stage 1: `source`

SigninLogs

Stage 2: `where`

| where TimeGenerated > ago(1d)

Stage 3: `where`

| where ResultType == 0

Stage 4: `where`

| where tolower(UserPrincipalName) in (admins)

References admins (defined above).

Stage 5: `where`

| where AutonomousSystemNumber !in (known_asns)

References known_asns (defined above).

Stage 6: `project-reorder`

| project-reorder TimeGenerated, UserPrincipalName, UserAgent, IPAddress, AutonomousSystemNumber

Stage 7: `extend`

| extend AccountName = tostring(split(UserPrincipalName, "@")[0]), AccountUPNSuffix = tostring(split(UserPrincipalName, "@")[1])

Exclusions

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

Field	Kind	Excluded values
`AutonomousSystemNumber`	eq	`known_asns`

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
`ResultType`	eq	`0` transforms: `cased`
`UserPrincipalName`	in	`admins` transforms: `tolower`, `cased`

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
`AccountName`	`extend`
`AccountUPNSuffix`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`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)

Privileged User Logon from new ASN

MITRE ATT&CK coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Let binding: `admins`

Let binding: `known_asns`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `project-reorder`

Stage 7: `extend`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Privileged User Logon from new ASN

MITRE ATT&CK coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Let binding: admins

Let binding: known_asns

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: where

Stage 6: project-reorder

Stage 7: extend

Exclusions

Indicators

Output fields

Let binding: `admins`

Let binding: `known_asns`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `project-reorder`

Stage 7: `extend`