Detection rules › Kusto
TI Map Domain entity to EmailUrlInfo
Identifies a match in EmailUrlInfo table from any Domain IOC from TI.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access |
Telemetry coverage
Rule body
id: b56e2290-c65b-45a5-9636-3651e85bbe5d
name: TI Map Domain entity to EmailUrlInfo
description: |
'Identifies a match in EmailUrlInfo table from any Domain IOC from TI.'
severity: Medium
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
dataTypes:
- EmailUrlInfo
- connectorId: ThreatIntelligence
dataTypes:
- ThreatIntelIndicators
- connectorId: ThreatIntelligenceTaxii
dataTypes:
- ThreatIntelIndicators
- connectorId: MicrosoftDefenderThreatIntelligence
dataTypes:
- ThreatIntelIndicators
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1566
query: |
let dt_lookBack = 1h; // Define the lookback period for email data as 1 hour
let ioc_lookBack = 14d; // Define the lookback period for threat intelligence data as 14 days
let EmailUrlInfo_ = EmailUrlInfo| where isnotempty(Url) or isnotempty(UrlDomain) // Filter for non-empty URLs or URL domains
| where TimeGenerated >= ago(dt_lookBack) // Filter for records within the lookback period
| extend Url = tolower(Url), UrlDomain = tolower(UrlDomain) // Convert URLs and domains to lowercase
| extend EmailUrlInfo_TimeGenerated = TimeGenerated; // Create a new column for the time generated
let EmailEvents_ = EmailEvents
| where TimeGenerated >= ago(dt_lookBack); // Filter email events within the lookback period
let TI_Urls = ThreatIntelIndicators
| where TimeGenerated >= ago(ioc_lookBack) // Filter threat intelligence indicators within the lookback period
| summarize arg_max(TimeGenerated, *) by Id, ObservableValue // Get latest record per Id FIRST
| where IsActive == true and ValidUntil > now() // THEN filter for active indicators that haven't expired
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where isnotempty(IndicatorType) and IndicatorType == "url"
| extend Url = tolower(ObservableValue)
| where isnotempty(Url) // Filter for non-empty URLs
| join kind=innerunique (EmailUrlInfo_) on Url // Join with email URL info on URL
| extend Description = tostring(parse_json(Data).description)
| extend ActivityGroupNames = extract("ActivityGroup:([^,]+)", 1, tostring(parse_json(Data).labels))
| project EmailUrlInfo_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, Url, UrlLocation, NetworkMessageId; // Select relevant columns
let TI_Domains = ThreatIntelIndicators
| where TimeGenerated >= ago(ioc_lookBack) // Filter threat intelligence indicators within the lookback period
| where isnotempty(ObservableValue) // Filter for non-empty domain names
| extend DomainName = tolower(ObservableValue) // Convert domain names to lowercase
| where ObservableKey == "domain-name:value"
| summarize arg_max(TimeGenerated, *) by Id, ObservableValue // Get latest record per Id FIRST
| where IsActive == true // THEN filter for active indicators
| extend TrafficLightProtocolLevel = AdditionalFields.TLPLevel
| extend IndicatorId = tostring(split(Id, "--")[2]);
let TI_Domains_UrlInfo = TI_Domains
| project-reorder *, IsActive, Tags, TrafficLightProtocolLevel, DomainName, Type
| join kind=innerunique (EmailUrlInfo_) on $left.DomainName == $right.UrlDomain // Join with email URL info on domain name
| extend ExpirationDateTime = ValidUntil
| extend Description = Data.description
| extend ThreatType = Data.type
| extend ConfidenceScore = Confidence
| extend ActivityGroupNames = replace_string(tostring(parse_json(tostring(Data.labels))[0]),"ActivityGroup:","")
| where ExpirationDateTime > now() // Filter for indicators that haven't expired
| project EmailUrlInfo_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, UrlDomain, UrlLocation, NetworkMessageId; // Select relevant columns
union TI_Urls, TI_Domains_UrlInfo // Combine URL and domain threat intelligence data
| extend timestamp = EmailUrlInfo_TimeGenerated // Add a timestamp column
| join kind=inner (EmailEvents_) on NetworkMessageId // Join with email events on network message ID
| where DeliveryAction !has "Blocked" // Filter out blocked delivery actions
| extend Name = tostring(split(RecipientEmailAddress, '@', 0)[0]), UPNSuffix = tostring(split(RecipientEmailAddress, '@', 1)[0]); // Extract name and UPN suffix from recipient email address"
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: RecipientEmailAddress
- identifier: Name
columnName: Name
- identifier: UPNSuffix
columnName: UPNSuffix
- entityType: URL
fieldMappings:
- identifier: Url
columnName: Url
version: 1.0.7
kind: Scheduled
Stages and Predicates
Stage 0: let
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let EmailUrlInfo_ = EmailUrlInfo| where isnotempty(Url) or isnotempty(UrlDomain)
| where TimeGenerated >= ago(dt_lookBack)
| extend Url = tolower(Url), UrlDomain = tolower(UrlDomain)
| extend EmailUrlInfo_TimeGenerated = TimeGenerated;
let EmailEvents_ = EmailEvents
| where TimeGenerated >= ago(dt_lookBack);
let TI_Urls = ThreatIntelIndicators <inlined as stages below>;
let TI_Domains = ThreatIntelIndicators <inlined as stages below>;
let TI_Domains_UrlInfo = TI_Domains <inlined as stages below>;
Stage 1: source
let EmailUrlInfo_
Stage 2: source
let EmailEvents_
Stage 3: source
let TI_Urls
Stage 4: source
let TI_Domains_UrlInfo
Stage 5: union
union of 2 branches
Stage 6: source
ThreatIntelIndicators
Stage 7: where
where TimeGenerated >= ago(1209600s)
Stage 8: summarize
summarize by Id, ObservableValue
Stage 9: where
where IsActive =~ true
Stage 10: extend
extend IndicatorType
Stage 11: where
where IndicatorType =~ "url" and isnotempty(IndicatorType)
Stage 12: extend
extend Url
Stage 13: where
where isnotempty(Url)
Stage 14: join
join kind=innerunique (EmailUrlInfo_) on Url
Stage 15: extend
extend Description
Stage 16: extend
extend ActivityGroupNames
Stage 17: project
project ActivityGroupNames, Confidence, Description, EmailUrlInfo_TimeGenerated, Id, NetworkMessageId, Url, UrlLocation, ValidUntil
Stage 18: source
ThreatIntelIndicators
Stage 19: where
where TimeGenerated >= ago(1209600s)
Stage 20: where
where isnotempty(ObservableValue)
Stage 21: extend
extend DomainName
Stage 22: where
where ObservableKey =~ "domain-name:value"
Stage 23: summarize
summarize by Id, ObservableValue
Stage 24: where
where IsActive =~ true
Stage 25: extend
extend TrafficLightProtocolLevel
Stage 26: extend
extend IndicatorId
Stage 27: project-reorder
project-reorder
Stage 28: join
join kind=innerunique (EmailUrlInfo_) on DomainName, UrlDomain
Stage 29: extend (5 consecutive steps)
extend ActivityGroupNames, ConfidenceScore, Description, ExpirationDateTime, ThreatType
Stage 30: where
where ExpirationDateTime > now()
Stage 31: project
project ActivityGroupNames, ConfidenceScore, Description, EmailUrlInfo_TimeGenerated, ExpirationDateTime, IndicatorId, NetworkMessageId, ThreatType, UrlDomain, UrlLocation
Stage 32: extend
extend timestamp
Stage 33: join
join kind=inner (EmailEvents_) on NetworkMessageId
Stage 34: where
where not (DeliveryAction contains "Blocked")
Stage 35: extend
extend Name, UPNSuffix
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
IndicatorType | eq |
| field:"IndicatorType" kind:eq value:"url" |
IndicatorType | is_not_null | field:"IndicatorType" kind:is_not_null | |
IsActive | eq |
| field:"IsActive" kind:eq value:"true" |
ObservableKey | eq |
| field:"ObservableKey" kind:eq value:"domain-name:value" |
ObservableValue | is_not_null | field:"ObservableValue" kind:is_not_null | |
Url | is_not_null | field:"Url" kind:is_not_null | |
UrlDomain | is_not_null | field:"UrlDomain" kind:is_not_null |
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
DeliveryAction | match | Blocked | excludes:DeliveryAction field:"DeliveryAction" value:"Blocked" |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
ActivityGroupNames | project |
ConfidenceScore | project |
Description | project |
EmailUrlInfo_TimeGenerated | project |
ExpirationDateTime | project |
IndicatorId | project |
NetworkMessageId | project |
ThreatType | project |
UrlDomain | project |
UrlLocation | project |
timestamp | extend |
Name | extend |
UPNSuffix | extend |