Detection rules › Kusto

TI Map IP entity to AWSCloudTrail

Severity
medium
Time window
14d
Group by
Id, ObservableValue, 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: 69f55be4-1b13-42d0-b975-a1e59c996dd2
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:
      - ThreatIntelIndicators
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelIndicators
  - connectorId: AWS
    dataTypes:
      - AWSCloudTrail
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelIndicators
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 = ThreatIntelIndicators
    //extract key part of kv pair
        | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
        | where IndicatorType in ("ipv4-addr", "ipv6-addr", "network-traffic")
        | extend NetworkSourceIP = toupper(ObservableValue)
        | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
    // Filter out indicators without relevant IP address fields
    | where TimeGenerated >= ago(ioc_lookBack)
    // Select the IP entity based on availability of different IP fields
    | extend TI_ipEntity = iff(isnotempty(NetworkSourceIP), NetworkSourceIP, NetworkSourceIP)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
    | extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
    // 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 Id, ObservableValue
    | where IsActive and (ValidUntil > now() or isempty(ValidUntil));
  // Perform a join between IP indicators and AWSCloudTrail logs to identify potential malicious activity
  IP_Indicators
     | project-reorder *, Tags, TrafficLightProtocolLevel, NetworkSourceIP, Type, TI_ipEntity
    // 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 < ValidUntil
    // Group the results by IndicatorId and SourceIpAddress, and keep the log entry with the latest timestamp
    | summarize AWSCloudTrail_TimeGenerated = arg_max(AWSCloudTrail_TimeGenerated, *) by Id, SourceIpAddress
    // Select the desired output fields
    | extend Description = tostring(parse_json(Data).description)
    | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
    | project AWSCloudTrail_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence,
      TI_ipEntity, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserIdentityUserName, SourceIpAddress,
      NetworkSourceIP, Url
    // 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: 1.4.7
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 10 define let IP_Indicators (the rule's main pipeline source); stages 11 to 18 run on it.

Stage 1: source

ThreatIntelIndicators

Stage 2: extend

| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))

Stage 3: where

| where IndicatorType in ("ipv4-addr", "ipv6-addr", "network-traffic")

Stage 4: extend

| extend NetworkSourceIP = toupper(ObservableValue)

Stage 5: extend

| extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)

Stage 6: where

| where TimeGenerated >= ago(ioc_lookBack)

Stage 7: extend (3 consecutive steps)

| extend TI_ipEntity = iff(isnotempty(NetworkSourceIP), NetworkSourceIP, NetworkSourceIP)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
| extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
TI_ipEntity =
ifisnotempty(NetworkSourceIP)NetworkSourceIP
elseNetworkSourceIP

Stage 8: where

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

Stage 9: summarize

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

Stage 10: where

| where IsActive and (ValidUntil > now() or isempty(ValidUntil))

Stage 11: project-reorder

IP_Indicators
| project-reorder *, Tags, TrafficLightProtocolLevel, NetworkSourceIP, Type, TI_ipEntity

Stage 12: join

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

Stage 13: where

| where AWSCloudTrail_TimeGenerated < ValidUntil

Stage 14: summarize

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

Stage 15: extend

| extend Description = tostring(parse_json(Data).description)

Stage 16: extend

| extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))

Stage 17: project

| project AWSCloudTrail_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence,
    TI_ipEntity, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserIdentityUserName, SourceIpAddress,
    NetworkSourceIP, Url

Stage 18: 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.

FieldKindValuesSearch
AWSCloudTrail_TimeGeneratedcross_field_compare
  • ValidUntil transforms: op:lt
field:"AWSCloudTrail_TimeGenerated" kind:cross_field_compare value:"ValidUntil"
IndicatorTypein
  • ipv4-addr
  • ipv6-addr
  • network-traffic
field:"IndicatorType" kind:in
ValidUntilis_null
  • (no value, null check)
field:"ValidUntil" kind:is_null

Output fields

These fields are emitted when the rule matches.

FieldSource
AWSCloudTrail_TimeGeneratedproject
ActivityGroupNamesproject
Confidenceproject
Descriptionproject
EventNameproject
EventTypeNameproject
Idproject
NetworkSourceIPproject
SourceIpAddressproject
TI_ipEntityproject
Urlproject
UserIdentityAccountIdproject
UserIdentityPrincipalidproject
UserIdentityUserNameproject
ValidUntilproject
timestampextend