Detection rules › Kusto

Infoblox - TI - Syslog Match Found - URL

Status
available
Severity
medium
Time window
14d
Group by
DomainName, IndicatorId, Url
Source
github.com/Azure/Azure-Sentinel

'Syslog URL match found in your Infoblox TIDE Threat Intelligence. Customize query count, scheduling, responses and more. Modify data sources, types and threat properties as desired.'

MITRE ATT&CK coverage

Rule body kusto

id: 28ee3c2b-eb4b-44de-a71e-e462843fea72
name: Infoblox - TI - Syslog Match Found - URL
description: |
  'Syslog URL match found in your Infoblox TIDE Threat Intelligence. Customize query count, scheduling, responses and more. Modify data sources, types and threat properties as desired.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: Syslog
    dataTypes: 
      - Syslog
  - connectorId: ThreatIntelligence
    dataTypes: 
      - ThreatIntelligenceIndicator
  - connectorId: CefAma
    dataTypes:
      - CommonSecurityLog
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Impact
relevantTechniques:
  - T1498
  - T1565
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let TI = ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()  
  | where Description has_cs "Infoblox - URL"
  | where isnotempty(DomainName)
  ;
  let Data = Syslog
  | extend HitTime = TimeGenerated
  | where TimeGenerated >= ago(dt_lookBack)
  //Extract URL patterns from syslog message
  | extend Url = extract("(http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\(\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+)", 1,SyslogMessage)
  | where isnotempty(Url)
  ;
  TI | join kind=innerunique Data on $left.DomainName == $right.Url
  | where HitTime >= TimeGenerated and HitTime < ExpirationDateTime
  | project LatestIndicatorTime, HitTime, SyslogMessage, Computer, ProcessName, Url, HostIP, 
  AdditionalInformation, Description, ThreatType, TrafficLightProtocolLevel, Type, ConfidenceScore, ExpirationDateTime, SourceSystem, Action, IndicatorId, ExternalIndicatorId, Tags
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: HostIP
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: Computer
  - entityType: DNS
    fieldMappings:
      - identifier: DomainName
        columnName: Url
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url
eventGroupingSettings:
  aggregationKind: SingleAlert
incidentConfiguration:
  createIncident: true
version: 1.0.3
kind: Scheduled

Stages and Predicates

Parameters

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

Let binding: Data

let Data = Syslog
| extend HitTime = TimeGenerated
| where TimeGenerated >= ago(dt_lookBack)
| extend Url = extract("(http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\(\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+)", 1,SyslogMessage)
| where isnotempty(Url);

Derived from dt_lookBack.

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

Stage 1: source

ThreatIntelligenceIndicator

Stage 2: where

| where TimeGenerated >= ago(ioc_lookBack)

Stage 3: summarize

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

Stage 4: where

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

Stage 5: where

| where Description has_cs "Infoblox - URL"

Stage 6: where

| where isnotempty(DomainName)

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

Stage 7: join

TI
| join kind=innerunique Data on $left.DomainName == $right.Url

Stage 8: where

| where HitTime >= TimeGenerated and HitTime < ExpirationDateTime

Stage 9: project

| project LatestIndicatorTime, HitTime, SyslogMessage, Computer, ProcessName, Url, HostIP, 
AdditionalInformation, Description, ThreatType, TrafficLightProtocolLevel, Type, ConfidenceScore, ExpirationDateTime, SourceSystem, Action, IndicatorId, ExternalIndicatorId, Tags

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
Descriptionmatch
  • Infoblox - URL transforms: cased, term
DomainNameis_not_null
  • (no value, null check)
HitTimege
  • TimeGenerated transforms: cased
HitTimelt
  • ExpirationDateTime transforms: cased
Urlis_not_null
  • (no value, null check)

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
Actionproject
AdditionalInformationproject
Computerproject
ConfidenceScoreproject
Descriptionproject
ExpirationDateTimeproject
ExternalIndicatorIdproject
HitTimeproject
HostIPproject
IndicatorIdproject
LatestIndicatorTimeproject
ProcessNameproject
SourceSystemproject
SyslogMessageproject
Tagsproject
ThreatTypeproject
TrafficLightProtocolLevelproject
Typeproject
Urlproject