Detection rules › Kusto

TI map IP entity to Azure Key Vault logs

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

Identifies a match in Azure Key Vault logs from any IP IOC from TI

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1071 Application Layer Protocol

Rule body kusto

id: 57c7e832-64eb-411f-8928-4133f01f4a25
name: TI map IP entity to Azure Key Vault logs
description: |
  Identifies a match in Azure Key Vault logs from any IP IOC from TI
severity: Medium
requiredDataConnectors:
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: AzureKeyVault
    dataTypes:
      - KeyVaultData
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
query: |
  let dt_lookBack = 1h; // Look back 1 hour for AzureDiagnostics logs
  let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
  // Fetch threat intelligence indicators related to IP addresses
  let IP_Indicators = ThreatIntelligenceIndicator
    | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
    | where TimeGenerated >= ago(ioc_lookBack)
    | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
    | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127."
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now();
  // Perform a join between IP indicators and AzureDiagnostics logs for Key Vault events
  IP_Indicators
    // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
    | join kind=innerunique (
        AzureDiagnostics
        | where ResourceType =~ "VAULTS"
        | where TimeGenerated >= ago(dt_lookBack)
        | extend KeyVaultEvents_TimeGenerated = TimeGenerated, ClientIP = CallerIPAddress
    )
    on $left.TI_ipEntity == $right.ClientIP
    // Filter out logs that occurred after the expiration of the corresponding indicator
    | where KeyVaultEvents_TimeGenerated < ExpirationDateTime
    // Group the results by IndicatorId and ClientIP, and keep the log entry with the latest timestamp
    | summarize KeyVaultEvents_TimeGenerated = arg_max(KeyVaultEvents_TimeGenerated, *) by IndicatorId, ClientIP
    // Select the desired output fields
    | project KeyVaultEvents_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
      TI_ipEntity, ClientIP, ResourceId, SubscriptionId, OperationName, ResultType, CorrelationId, id_s, clientInfo_s, httpStatusCode_d,
      identity_claim_appid_g, identity_claim_http_schemas_microsoft_com_identity_claims_objectidentifier_g, Type
    // Rename the timestamp field
    | extend timestamp = KeyVaultEvents_TimeGenerated
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: ClientIP
  - entityType: AzureResource
    fieldMappings:
      - identifier: ResourceId
        columnName: ResourceId
version: 1.3.4
kind: Scheduled

Stages and Predicates

Parameters

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

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

Stage 1: source

ThreatIntelligenceIndicator

Stage 2: where

| where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)

Stage 3: where

| where TimeGenerated >= ago(ioc_lookBack)

Stage 4: extend (3 consecutive steps)

| extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
TI_ipEntity =
ifisnotempty(NetworkIP)NetworkIP
elseNetworkDestinationIP

Stage 5: where

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

Stage 6: summarize

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

Stage 7: where

| where Active == true and ExpirationDateTime > now()

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

Stage 8: join

IP_Indicators
| join kind=innerunique (
      AzureDiagnostics
      | where ResourceType =~ "VAULTS"
      | where TimeGenerated >= ago(dt_lookBack)
      | extend KeyVaultEvents_TimeGenerated = TimeGenerated, ClientIP = CallerIPAddress
  )
  on $left.TI_ipEntity == $right.ClientIP

Stage 9: where

| where KeyVaultEvents_TimeGenerated < ExpirationDateTime

Stage 10: summarize

| summarize KeyVaultEvents_TimeGenerated = arg_max(KeyVaultEvents_TimeGenerated, *) by IndicatorId, ClientIP

Stage 11: project

| project KeyVaultEvents_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
    TI_ipEntity, ClientIP, ResourceId, SubscriptionId, OperationName, ResultType, CorrelationId, id_s, clientInfo_s, httpStatusCode_d,
    identity_claim_appid_g, identity_claim_http_schemas_microsoft_com_identity_claims_objectidentifier_g, Type

Stage 12: extend

| extend timestamp = KeyVaultEvents_TimeGenerated

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
Activeeq
  • true transforms: cased
EmailSourceIpAddressis_not_null
  • (no value, null check)
KeyVaultEvents_TimeGeneratedlt
  • ExpirationDateTime transforms: cased
NetworkDestinationIPis_not_null
  • (no value, null check)
NetworkIPis_not_null
  • (no value, null check)
NetworkSourceIPis_not_null
  • (no value, null check)
ResourceTypeeq
  • VAULTS

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
ActivityGroupNamesproject
ClientIPproject
ConfidenceScoreproject
CorrelationIdproject
Descriptionproject
ExpirationDateTimeproject
IndicatorIdproject
KeyVaultEvents_TimeGeneratedproject
OperationNameproject
ResourceIdproject
ResultTypeproject
SubscriptionIdproject
TI_ipEntityproject
ThreatTypeproject
Typeproject
Urlproject
clientInfo_sproject
httpStatusCode_dproject
id_sproject
identity_claim_appid_gproject
identity_claim_http_schemas_microsoft_com_identity_claims_objectidentifier_gproject
timestampextend