Detection rules › Kusto
Preview - TI map URL entity to Cloud App Events
'Identifies compromises and attacks and detect malicious activities in one's URL entity from TI'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1071 Application Layer Protocol |
Rule body kusto
id: e8ae92dd-1d41-4530-8be8-85c5014c7b47
name: Preview - TI map URL entity to Cloud App Events
description: |
'Identifies compromises and attacks and detect malicious activities in one's URL 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;
ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| where isnotempty(Url)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| join kind=innerunique (CloudAppEvents
| where TimeGenerated >= ago(dt_lookBack)
| extend Url = extract("(http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\(\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+)", 1, tostring(ActivityObjects))
| extend userPrincipalName = tostring(RawEventData.UserId)
| extend TargetResourceDisplayName = tostring(ActivityObjects[0].displayName)
| extend CloudApps_TimeGenerated = TimeGenerated) on Url
| where CloudApps_TimeGenerated < ExpirationDateTime
| summarize CloudApps_TimeGenerated = argmax(CloudApps_TimeGenerated, *) by IndicatorId, Url
| extend Description = max_CloudApps_TimeGenerated_Description, ActivityGroupNames = max_CloudApps_TimeGenerated_ActivityGroupNames, ThreatType = max_CloudApps_TimeGenerated_ThreatType, ExpirationDateTime = max_CloudApps_TimeGenerated_ExpirationDateTime, ConfidenceScore = max_CloudApps_TimeGenerated_ConfidenceScore, IPAddress = max_CloudApps_TimeGenerated_IPAddress, AccountObjectId = max_CloudApps_TimeGenerated_AccountObjectId, AccountDisplayName = max_CloudApps_TimeGenerated_AccountDisplayName, ObjectName = max_CloudApps_TimeGenerated_ObjectName, Application= max_CloudApps_TimeGenerated_Application, ApplicationID = max_CloudApps_TimeGenerated_ApplicationId, userPrincipalName = max_CloudApps_TimeGenerated_userPrincipalName
| project CloudApps_TimeGenerated, Description, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, IPAddress, userPrincipalName, AccountObjectId, AccountDisplayName, ObjectName, Application, ApplicationID
entityMappings:
- entityType: Account
fieldMappings:
- identifier: ObjectGuid
columnName: AccountObjectId
- identifier: FullName
columnName: userPrincipalName
- identifier: DisplayName
columnName: AccountDisplayName
- entityType: URL
fieldMappings:
- identifier: Url
columnName: Url
- entityType: IP
fieldMappings:
- identifier: Address
columnName: IPAddress
- entityType: CloudApplication
fieldMappings:
- identifier: Name
columnName: Application
- identifier: AppId
columnName: ApplicationID
version: 1.0.3
kind: Scheduled
Stages and Predicates
Parameters
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
Stage 1: source
ThreatIntelligenceIndicator
Stage 2: where
| where TimeGenerated >= ago(ioc_lookBack)
Stage 3: where
| where isnotempty(Url)
Stage 4: summarize
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
Stage 5: where
| where Active == true and ExpirationDateTime > now()
Stage 6: join
| join kind=innerunique (CloudAppEvents
| where TimeGenerated >= ago(dt_lookBack)
| extend Url = extract("(http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\(\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+)", 1, tostring(ActivityObjects))
| extend userPrincipalName = tostring(RawEventData.UserId)
| extend TargetResourceDisplayName = tostring(ActivityObjects[0].displayName)
| extend CloudApps_TimeGenerated = TimeGenerated) on Url
Stage 7: where
| where CloudApps_TimeGenerated < ExpirationDateTime
Stage 8: summarize
| summarize CloudApps_TimeGenerated = argmax(CloudApps_TimeGenerated, *) by IndicatorId, Url
Stage 9: extend
| extend Description = max_CloudApps_TimeGenerated_Description, ActivityGroupNames = max_CloudApps_TimeGenerated_ActivityGroupNames, ThreatType = max_CloudApps_TimeGenerated_ThreatType, ExpirationDateTime = max_CloudApps_TimeGenerated_ExpirationDateTime, ConfidenceScore = max_CloudApps_TimeGenerated_ConfidenceScore, IPAddress = max_CloudApps_TimeGenerated_IPAddress, AccountObjectId = max_CloudApps_TimeGenerated_AccountObjectId, AccountDisplayName = max_CloudApps_TimeGenerated_AccountDisplayName, ObjectName = max_CloudApps_TimeGenerated_ObjectName, Application= max_CloudApps_TimeGenerated_Application, ApplicationID = max_CloudApps_TimeGenerated_ApplicationId, userPrincipalName = max_CloudApps_TimeGenerated_userPrincipalName
Stage 10: project
| project CloudApps_TimeGenerated, Description, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, IPAddress, userPrincipalName, AccountObjectId, AccountDisplayName, ObjectName, Application, ApplicationID
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 |
|
CloudApps_TimeGenerated | lt |
|
Url | 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 |
|---|---|
AccountDisplayName | project |
AccountObjectId | project |
Application | project |
ApplicationID | project |
CloudApps_TimeGenerated | project |
ConfidenceScore | project |
Description | project |
ExpirationDateTime | project |
IPAddress | project |
IndicatorId | project |
ObjectName | project |
ThreatType | project |
Url | project |
userPrincipalName | project |