Detection rules › Kusto
Preview - TI map Domain entity to Cloud App Events
'Identifies compromises and attacks and detect malicious activities in one's domain entity from TI.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1071 Application Layer Protocol |
Rule body kusto
id: b97e118c-b7fa-42a6-84de-2e13443fbb8f
name: Preview - TI map Domain entity to Cloud App Events
description: |
'Identifies compromises and attacks and detect malicious activities in one's domain entity from TI.'
severity: Medium
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
dataTypes:
- CloudAppEvents
- connectorId: MicrosoftDefenderThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
- CommandAndControl
relevantTechniques:
- T1071
query: |
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let list_tlds =
ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| where isnotempty(DomainName)
| extend DomainName = tolower(DomainName)
| extend parts = split(DomainName, '.')
| extend tld = parts[(array_length(parts) - 1)]
| summarize count() by tostring(tld)
| summarize make_set(tld);
let Domain_Indicators =
ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| extend TI_DomainEntity = DomainName
| where isnotempty(TI_DomainEntity);
Domain_Indicators
| join kind=innerunique (
CloudAppEvents
| extend IngestionTime = ingestion_time()
| where IngestionTime > ago(dt_lookBack)
| extend PAUrl = columnifexists("RequestURL", "None")
| extend Domain = trim('"', tostring(parseurl(PAUrl).Host))
| extend Domain = tolower(Domain)
| extend parts = split(Domain, '.')
| extend tld = parts[(array_length(parts) - 1)]
| extend CloudAppEvents_TimeGenerated = TimeGenerated) on $left.TI_DomainEntity == $right.Domain
| where CloudAppEvents_TimeGenerated < ExpirationDateTime
| summarize CloudAppEvents_TimeGenerated = argmax(CloudAppEvents_TimeGenerated, *) by IndicatorId
| extend Description = max_CloudAppEvents_TimeGenerated_Description, ActivityGroupNames = max_CloudAppEvents_TimeGenerated_ActivityGroupNames, ThreatType = max_CloudAppEvents_TimeGenerated_ThreatType, ExpirationDateTime = max_CloudAppEvents_TimeGenerated_ExpirationDateTime, ConfidenceScore = max_CloudAppEvents_TimeGenerated_ConfidenceScore, DomainName = max_CloudAppEvents_TimeGenerated_DomainName, ProviderName = max_CloudAppEvents_TimeGenerated_IndicatorProvider, AlertSeverity = max_CloudAppEvents_TimeGenerated_ThreatSeverity, IPAddress = max_CloudAppEvents_TimeGenerated_IPAddress
| project CloudAppEvents_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, DomainName, ProviderName, AlertSeverity, IPAddress
entityMappings:
- entityType: DNS
fieldMappings:
- identifier: DomainName
columnName: DomainName
- entityType: IP
fieldMappings:
- identifier: Address
columnName: IPAddress
version: 1.0.3
kind: Scheduled
Stages and Predicates
Parameters
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
Let binding: list_tlds
let list_tlds = ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| where isnotempty(DomainName)
| extend DomainName = tolower(DomainName)
| extend parts = split(DomainName, '.')
| extend tld = parts[(array_length(parts) - 1)]
| summarize count() by tostring(tld)
| summarize make_set(tld);
Derived from ioc_lookBack.
The stages below define let Domain_Indicators (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: extend
| extend TI_DomainEntity = DomainName
Stage 6: where
| where isnotempty(TI_DomainEntity)
The stages below run on Domain_Indicators (the outer pipeline).
Stage 7: join
Domain_Indicators
| join kind=innerunique (
CloudAppEvents
| extend IngestionTime = ingestion_time()
| where IngestionTime > ago(dt_lookBack)
| extend PAUrl = columnifexists("RequestURL", "None")
| extend Domain = trim('"', tostring(parseurl(PAUrl).Host))
| extend Domain = tolower(Domain)
| extend parts = split(Domain, '.')
| extend tld = parts[(array_length(parts) - 1)]
| extend CloudAppEvents_TimeGenerated = TimeGenerated) on $left.TI_DomainEntity == $right.Domain
Stage 8: where
| where CloudAppEvents_TimeGenerated < ExpirationDateTime
Stage 9: summarize
| summarize CloudAppEvents_TimeGenerated = argmax(CloudAppEvents_TimeGenerated, *) by IndicatorId
Stage 10: extend
| extend Description = max_CloudAppEvents_TimeGenerated_Description, ActivityGroupNames = max_CloudAppEvents_TimeGenerated_ActivityGroupNames, ThreatType = max_CloudAppEvents_TimeGenerated_ThreatType, ExpirationDateTime = max_CloudAppEvents_TimeGenerated_ExpirationDateTime, ConfidenceScore = max_CloudAppEvents_TimeGenerated_ConfidenceScore, DomainName = max_CloudAppEvents_TimeGenerated_DomainName, ProviderName = max_CloudAppEvents_TimeGenerated_IndicatorProvider, AlertSeverity = max_CloudAppEvents_TimeGenerated_ThreatSeverity, IPAddress = max_CloudAppEvents_TimeGenerated_IPAddress
Stage 11: project
| project CloudAppEvents_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, DomainName, ProviderName, AlertSeverity, IPAddress
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.
| Field | Kind | Values |
|---|---|---|
Active | eq |
|
CloudAppEvents_TimeGenerated | lt |
|
TI_DomainEntity | is_not_null |
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.
| Field | Source |
|---|---|
ActivityGroupNames | project |
AlertSeverity | project |
CloudAppEvents_TimeGenerated | project |
ConfidenceScore | project |
Description | project |
DomainName | project |
ExpirationDateTime | project |
IPAddress | project |
IndicatorId | project |
ProviderName | project |
ThreatType | project |