Detection rules › Kusto

Lumen TI IPAddress in SigninLogs

Severity
medium
Time window
14d
Group by
Id, SL_ipEntity, TI_ipEntity
Source
github.com/Azure/Azure-Sentinel

This query maps Lumen IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in SigninLogs.

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1071 Application Layer Protocol

Rule body kusto

id: 1425aea5-a9e5-4288-886e-934b90664a91
name: Lumen TI IPAddress in SigninLogs
displayName: Lumen TI IPAddress in SigninLogs
description: |
  This query maps Lumen IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in SigninLogs.
severity: Medium
requiredDataConnectors:
  - connectorId: LumenThreatFeedConnector
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceUploadIndicatorsAPI
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: AzureActiveDirectory
    dataTypes:
      - SigninLogs
queryFrequency: 4h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
suppressionDuration: 5h
suppressionEnabled: true
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
query: |
  let dt_lookBack = 1d;  // Data lookback for SigninLogs
  let ioc_lookBack = 14d; // TI lookback
  let IP_Indicators = ThreatIntelIndicators
    | where TimeGenerated >= ago(ioc_lookBack)
    | where IsActive == true and ValidUntil > now()
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id
    | where SourceSystem == 'Lumen'
    | where ObservableKey == 'ipv4-addr:value'
    | extend TI_ipEntity = ObservableValue
    | where ipv4_is_private(TI_ipEntity) == false and TI_ipEntity !startswith 'fe80' and TI_ipEntity !startswith '::' and TI_ipEntity !startswith '127.';
  IP_Indicators
  | join kind=innerunique (
      SigninLogs
      | where TimeGenerated >= ago(dt_lookBack)
      | extend SL_ipEntity = IPAddress
      | extend SigninLogs_TimeGenerated = TimeGenerated
    ) on $left.TI_ipEntity == $right.SL_ipEntity
  | where SigninLogs_TimeGenerated < ValidUntil
  | summarize arg_max(SigninLogs_TimeGenerated, *), StartTime = min(SigninLogs_TimeGenerated), EndTime = max(SigninLogs_TimeGenerated) by Id, SL_ipEntity
  | project timestamp = EndTime, StartTime, EndTime, UserPrincipalName, IPAddress, ResultType, AppDisplayName, Id, Tags, ValidUntil, Confidence, TI_ipEntity, SL_ipEntity, Type
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SL_ipEntity
version: 1.0.0
kind: Scheduled

Stages and Predicates

Parameters

let dt_lookBack = 1d;
let ioc_lookBack = 14d;

The stages below define let IP_Indicators (the rule's main pipeline source).

Stage 1: source

ThreatIntelIndicators

Stage 2: where

| where TimeGenerated >= ago(ioc_lookBack)

Stage 3: where

| where IsActive == true and ValidUntil > now()

Stage 4: summarize

| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id

Stage 5: where

| where SourceSystem == 'Lumen'

Stage 6: where

| where ObservableKey == 'ipv4-addr:value'

Stage 7: extend

| extend TI_ipEntity = ObservableValue

Stage 8: where

| where ipv4_is_private(TI_ipEntity) == false and TI_ipEntity !startswith 'fe80' and TI_ipEntity !startswith '::' and TI_ipEntity !startswith '127.'

The stages below run on IP_Indicators (the outer pipeline).

Stage 9: join

IP_Indicators
| join kind=innerunique (
    SigninLogs
    | where TimeGenerated >= ago(dt_lookBack)
    | extend SL_ipEntity = IPAddress
    | extend SigninLogs_TimeGenerated = TimeGenerated
  ) on $left.TI_ipEntity == $right.SL_ipEntity

Stage 10: where

| where SigninLogs_TimeGenerated < ValidUntil

Stage 11: summarize

| summarize arg_max(SigninLogs_TimeGenerated, *), StartTime = min(SigninLogs_TimeGenerated), EndTime = max(SigninLogs_TimeGenerated) by Id, SL_ipEntity

Stage 12: project

| project timestamp = EndTime, StartTime, EndTime, UserPrincipalName, IPAddress, ResultType, AppDisplayName, Id, Tags, ValidUntil, Confidence, TI_ipEntity, SL_ipEntity, Type

Exclusions

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

FieldKindExcluded values
TI_ipEntitycidr_match10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 169.254.0.0/16, 127.0.0.0/8
TI_ipEntitystarts_with127.
TI_ipEntitystarts_with::
TI_ipEntitystarts_withfe80

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
IsActiveeq
  • true transforms: cased
ObservableKeyeq
  • ipv4-addr:value transforms: cased
SigninLogs_TimeGeneratedlt
  • ValidUntil transforms: cased
SourceSystemeq
  • Lumen transforms: 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.

FieldSource
AppDisplayNameproject
Confidenceproject
EndTimeproject
IPAddressproject
Idproject
ResultTypeproject
SL_ipEntityproject
StartTimeproject
TI_ipEntityproject
Tagsproject
Typeproject
UserPrincipalNameproject
ValidUntilproject
timestampproject