Detection rules › Kusto

TI map IP entity to AWSCloudTrail

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

Identifies a match in AWSCloudTrail from any IP IOC from TI

MITRE ATT&CK coverage

TacticTechniques
Command & Control

Rule body

id: f110287e-1358-490d-8147-ed804b328514
name: TI map IP entity to AWSCloudTrail
description: |
  Identifies a match in AWSCloudTrail from any IP IOC from TI
severity: Medium
requiredDataConnectors:
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: AWS
    dataTypes:
      - AWSCloudTrail
  - 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 AWSCloudTrail 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
    // Filter out indicators without relevant IP address fields
    | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
    | where TimeGenerated >= ago(ioc_lookBack)
    // Select the IP entity based on availability of different IP fields
    | 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)
    // Exclude local addresses using the ipv4_is_private operator and filtering out specific address prefixes
    | 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 AWSCloudTrail logs to identify potential malicious activity
  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 (
        AWSCloudTrail
        | where TimeGenerated >= ago(dt_lookBack)
        | extend AWSCloudTrail_TimeGenerated = TimeGenerated // Rename time column for clarity
      )
      on $left.TI_ipEntity == $right.SourceIpAddress
    // Filter out logs that occurred after the expiration of the corresponding indicator
    | where AWSCloudTrail_TimeGenerated < ExpirationDateTime
    // Group the results by IndicatorId and SourceIpAddress, and keep the log entry with the latest timestamp
    | summarize AWSCloudTrail_TimeGenerated = arg_max(AWSCloudTrail_TimeGenerated, *) by IndicatorId, SourceIpAddress
    // Select the desired output fields
    | project AWSCloudTrail_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
      TI_ipEntity, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserIdentityUserName, SourceIpAddress,
      NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
    // Rename the timestamp field
    | extend timestamp = AWSCloudTrail_TimeGenerated
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: ObjectGuid
        columnName: UserIdentityUserName
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIpAddress
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url
version: 1.4.2
kind: Scheduled

Stages and Predicates

Parameters

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

let IP_Indicators is inlined into the numbered stages below.

Stages 1 to 7 define let IP_Indicators (the rule's main pipeline source); stages 8 to 12 run on it.

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()

Stage 8: join

IP_Indicators
| join kind=innerunique (
      AWSCloudTrail
      | where TimeGenerated >= ago(dt_lookBack)
      | extend AWSCloudTrail_TimeGenerated = TimeGenerated
    )
    on $left.TI_ipEntity == $right.SourceIpAddress

Stage 9: where

| where AWSCloudTrail_TimeGenerated < ExpirationDateTime

Stage 10: summarize

| summarize AWSCloudTrail_TimeGenerated = arg_max(AWSCloudTrail_TimeGenerated, *) by IndicatorId, SourceIpAddress

Stage 11: project

| project AWSCloudTrail_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
    TI_ipEntity, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserIdentityUserName, SourceIpAddress,
    NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type

Stage 12: extend

| extend timestamp = AWSCloudTrail_TimeGenerated

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
TI_ipEntitycidr_match10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 169.254.0.0/16, 127.0.0.0/8excludes:TI_ipEntity
TI_ipEntitystarts_with127.excludes:TI_ipEntity field:"TI_ipEntity" value:"127."
TI_ipEntitystarts_with::excludes:TI_ipEntity field:"TI_ipEntity" value:"::"
TI_ipEntitystarts_withfe80excludes:TI_ipEntity field:"TI_ipEntity" value:"fe80"

Indicators

These rows show field, operator, and value matches.

Output fields

These fields are emitted when the rule matches.

FieldSource
AWSCloudTrail_TimeGeneratedproject
ActivityGroupNamesproject
ConfidenceScoreproject
Descriptionproject
EmailSourceIpAddressproject
EventNameproject
EventTypeNameproject
ExpirationDateTimeproject
IndicatorIdproject
NetworkDestinationIPproject
NetworkIPproject
NetworkSourceIPproject
SourceIpAddressproject
TI_ipEntityproject
ThreatTypeproject
Typeproject
Urlproject
UserIdentityAccountIdproject
UserIdentityPrincipalidproject
UserIdentityUserNameproject
timestampextend