Detection rules › Kusto
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: a7d2b1e4-dd9c-40fd-9651-1a136eb8f0df
name: 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:
- ThreatIntelIndicators
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
- CommandAndControl
relevantTechniques:
- T1071
query: |
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let list_tlds =
ThreatIntelIndicators
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
//extract key part of kv pair
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "domain-name"
| extend DomainName = tolower(IndicatorType)
| extend parts = split(DomainName, '.')
| extend tld = parts[(array_length(parts) - 1)]
| extend IndicatorId = tostring(split(Id, "--")[2])
| summarize count() by tostring(tld)
| summarize make_set(tld);
let Domain_Indicators =
ThreatIntelIndicators
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "domain-name"
| extend DomainName = tolower(ObservableValue)
| extend IndicatorId = tostring(split(Id, "--")[2])
| project-reorder *, IndicatorType, DomainName, Type;
Domain_Indicators
| join kind=innerunique (
CloudAppEvents
| extend IngestionTime = ingestion_time()
| where IngestionTime > ago(dt_lookBack)
| extend PAUrl = columnifexists("RequestURL", "None")
| extend Domain = tolower(trim('"', tostring(parseurl(PAUrl).Host)))
| extend parts = split(Domain, '.')
| extend tld = parts[(array_length(parts) - 1)]
| extend CloudAppEvents_TimeGenerated = TimeGenerated) on $left.DomainName == $right.Domain
| where CloudAppEvents_TimeGenerated < ValidUntil
| summarize CloudAppEvents_TimeGenerated = argmax(CloudAppEvents_TimeGenerated, *) by IndicatorId
| extend
Description = tostring(parse_json(max_CloudAppEvents_TimeGenerated_Data).description),
ActivityGroupNames = column_ifexists("max_CloudAppEvents_TimeGenerated_ActivityGroupNames", ""),
ThreatType = column_ifexists("max_CloudAppEvents_TimeGenerated_ThreatType", ""),
ExpirationDateTime = column_ifexists("max_CloudAppEvents_TimeGenerated_ExpirationDateTime", ""),
ConfidenceScore = column_ifexists("max_CloudAppEvents_TimeGenerated_ConfidenceScore", ""),
DomainName = column_ifexists("max_CloudAppEvents_TimeGenerated_DomainName", ""),
ProviderName = column_ifexists("max_CloudAppEvents_TimeGenerated_IndicatorProvider", ""),
AlertSeverity = column_ifexists("max_CloudAppEvents_TimeGenerated_ThreatSeverity", ""),
IPAddress = column_ifexists("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: 1.0.6
kind: Scheduled
Stages and Predicates
Parameters
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
Let binding: list_tlds
let list_tlds = ThreatIntelIndicators
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "domain-name"
| extend DomainName = tolower(IndicatorType)
| extend parts = split(DomainName, '.')
| extend tld = parts[(array_length(parts) - 1)]
| extend IndicatorId = tostring(split(Id, "--")[2])
| 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
ThreatIntelIndicators
Stage 2: where
| where TimeGenerated >= ago(ioc_lookBack)
Stage 3: summarize
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
Stage 4: where
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
Stage 5: extend
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
Stage 6: where
| where IndicatorType == "domain-name"
Stage 7: extend
| extend DomainName = tolower(ObservableValue)
Stage 8: extend
| extend IndicatorId = tostring(split(Id, "--")[2])
Stage 9: project-reorder
| project-reorder *, IndicatorType, DomainName, Type
The stages below run on Domain_Indicators (the outer pipeline).
Stage 10: join
Domain_Indicators
| join kind=innerunique (
CloudAppEvents
| extend IngestionTime = ingestion_time()
| where IngestionTime > ago(dt_lookBack)
| extend PAUrl = columnifexists("RequestURL", "None")
| extend Domain = tolower(trim('"', tostring(parseurl(PAUrl).Host)))
| extend parts = split(Domain, '.')
| extend tld = parts[(array_length(parts) - 1)]
| extend CloudAppEvents_TimeGenerated = TimeGenerated) on $left.DomainName == $right.Domain
Stage 11: where
| where CloudAppEvents_TimeGenerated < ValidUntil
Stage 12: summarize
| summarize CloudAppEvents_TimeGenerated = argmax(CloudAppEvents_TimeGenerated, *) by IndicatorId
Stage 13: extend
| extend
Description = tostring(parse_json(max_CloudAppEvents_TimeGenerated_Data).description),
ActivityGroupNames = column_ifexists("max_CloudAppEvents_TimeGenerated_ActivityGroupNames", ""),
ThreatType = column_ifexists("max_CloudAppEvents_TimeGenerated_ThreatType", ""),
ExpirationDateTime = column_ifexists("max_CloudAppEvents_TimeGenerated_ExpirationDateTime", ""),
ConfidenceScore = column_ifexists("max_CloudAppEvents_TimeGenerated_ConfidenceScore", ""),
DomainName = column_ifexists("max_CloudAppEvents_TimeGenerated_DomainName", ""),
ProviderName = column_ifexists("max_CloudAppEvents_TimeGenerated_IndicatorProvider", ""),
AlertSeverity = column_ifexists("max_CloudAppEvents_TimeGenerated_ThreatSeverity", ""),
IPAddress = column_ifexists("max_CloudAppEvents_TimeGenerated_IPAddress", "")
Stage 14: 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 |
|---|---|---|
CloudAppEvents_TimeGenerated | lt |
|
IndicatorType | eq |
|
ValidUntil | is_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 |