TI map Domain entity to EmailEvents

Severity: medium
Time window: 14d
Group by: DomainName, Id, ObservableValue, RecipientEmailAddress, RecipientEmailDomain, SenderFromDomain
Source: github.com/Azure/Azure-Sentinel

Identifies a match in EmailEvents table from any Domain IOC from TI

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1566` Phishing

Rule body kusto

id: bc3bb047-70b8-4a4b-ac21-e3b1172881a4
name: TI map Domain entity to EmailEvents
description: |
  Identifies a match in EmailEvents table from any Domain IOC from TI
severity: Medium
requiredDataConnectors:
  - connectorId: Office365
    dataTypes:
      - EmailEvents
  - 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;
  let ioc_lookBack = 14d;
  let EmailEvents_ = materialize(EmailEvents | where isnotempty(RecipientEmailAddress) and isnotempty(SenderFromAddress) and TimeGenerated >= ago(dt_lookBack) and DeliveryAction !has "Blocked" | project-rename  EmailEvents_TimeGenerated = TimeGenerated | extend SenderFromDomain = tolower(SenderFromDomain) | extend RecipientEmailDomain = tolower(tostring(split(RecipientEmailAddress, '@', 1))));
  let SenderDomains = EmailEvents_ | distinct  SenderFromDomain | summarize make_list(SenderFromDomain);
  let RecipientDomains = EmailEvents_ | distinct  RecipientEmailDomain | summarize make_list(RecipientEmailDomain);
  let TI = materialize(ThreatIntelIndicators
  | where TimeGenerated >= ago(ioc_lookBack)
  | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
  | where IndicatorType == "domain-name"
  | extend DomainName = tolower(ObservableValue)
  | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
  | extend IndicatorId = tostring(split(Id, "--")[2])
  | where DomainName in (SenderDomains) or DomainName in (RecipientDomains)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
  | where IsActive and (ValidUntil > now() or isempty(ValidUntil))
  | extend Description = tostring(parse_json(Data).description)
  | where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;");
  (union
    (TI | join kind=innerunique (EmailEvents_) on $left.DomainName == $right.SenderFromDomain),
    (TI | join kind=innerunique (EmailEvents_) on $left.DomainName == $right.RecipientEmailDomain))
  | where EmailEvents_TimeGenerated < ValidUntil
  | extend ActivityGroupNames = extract("ActivityGroup:([^,]+)", 1, tostring(parse_json(Data).labels))
  | summarize EmailEvents_TimeGenerated = arg_max(EmailEvents_TimeGenerated, *) by Id, RecipientEmailAddress
  | project EmailEvents_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, DomainName, RecipientEmailAddress, SenderFromAddress, Subject, ConfidenceLevel, Type, TrafficLightProtocolLevel, DeliveryAction, DeliveryLocation, EmailDirection
  | extend Name = tostring(split(RecipientEmailAddress, '@', 0)[0]), UPNSuffix = tostring(split(RecipientEmailAddress, '@', 1)[0])
  | extend timestamp = EmailEvents_TimeGenerated
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: RecipientEmailAddress
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
version: 1.0.4
kind: Scheduled

Stages and Predicates

Parameters

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

Let binding: `EmailEvents_`

let EmailEvents_ = materialize(EmailEvents | where isnotempty(RecipientEmailAddress) and isnotempty(SenderFromAddress) and TimeGenerated >= ago(dt_lookBack) and DeliveryAction !has "Blocked" | project-rename  EmailEvents_TimeGenerated = TimeGenerated | extend SenderFromDomain = tolower(SenderFromDomain) | extend RecipientEmailDomain = tolower(tostring(split(RecipientEmailAddress, '@', 1))));

Derived from dt_lookBack.

Let binding: `SenderDomains`

let SenderDomains = EmailEvents_ | distinct  SenderFromDomain | summarize make_list(SenderFromDomain);

Derived from EmailEvents_.

Let binding: `RecipientDomains`

let RecipientDomains = EmailEvents_ | distinct  RecipientEmailDomain | summarize make_list(RecipientEmailDomain);

Derived from EmailEvents_.

Let binding: `TI`

let TI = materialize(ThreatIntelIndicators
| where TimeGenerated >= ago(ioc_lookBack)
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "domain-name"
| extend DomainName = tolower(ObservableValue)
| extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
| extend IndicatorId = tostring(split(Id, "--")[2])
| where DomainName in (SenderDomains) or DomainName in (RecipientDomains)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
| extend Description = tostring(parse_json(Data).description)
| where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;");

Derived from ioc_lookBack, SenderDomains, RecipientDomains.

union (2 sources)

Each leg below queries one source; the rule matches if any leg does. Sources: TI, TI

Leg 1: `TI`

TI | join kind=innerunique (EmailEvents_) on $left.DomainName == $right.SenderFromDomain

Leg 2: `TI`

TI | join kind=innerunique (EmailEvents_) on $left.DomainName == $right.RecipientEmailDomain

Applied to the combined result

| where EmailEvents_TimeGenerated < ValidUntil
| extend ActivityGroupNames = extract("ActivityGroup:([^,]+)", 1, tostring(parse_json(Data).labels))
| summarize EmailEvents_TimeGenerated = arg_max(EmailEvents_TimeGenerated, *) by Id, RecipientEmailAddress
| project EmailEvents_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, DomainName, RecipientEmailAddress, SenderFromAddress, Subject, ConfidenceLevel, Type, TrafficLightProtocolLevel, DeliveryAction, DeliveryLocation, EmailDirection
| extend Name = tostring(split(RecipientEmailAddress, '@', 0)[0]), UPNSuffix = tostring(split(RecipientEmailAddress, '@', 1)[0])
| extend timestamp = EmailEvents_TimeGenerated

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`Description`	contains	`State: falsepos;`
`Description`	contains	`State: inactive;`
`DeliveryAction`	match	`Blocked`
`Description`	contains	`State: falsepos;`
`Description`	contains	`State: inactive;`
`DeliveryAction`	match	`Blocked`

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
`DomainName`	in	`RecipientDomains` transforms: `cased` `SenderDomains` transforms: `cased`
`EmailEvents_TimeGenerated`	lt	`ValidUntil` transforms: `cased`
`IndicatorType`	eq	`domain-name` transforms: `cased`
`RecipientEmailAddress`	is_not_null	(no value, null check)
`SenderFromAddress`	is_not_null	(no value, null check)
`ValidUntil`	is_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.

Field	Source
`ActivityGroupNames`	`project`
`Confidence`	`project`
`ConfidenceLevel`	`project`
`DeliveryAction`	`project`
`DeliveryLocation`	`project`
`Description`	`project`
`DomainName`	`project`
`EmailDirection`	`project`
`EmailEvents_TimeGenerated`	`project`
`Id`	`project`
`RecipientEmailAddress`	`project`
`SenderFromAddress`	`project`
`Subject`	`project`
`TrafficLightProtocolLevel`	`project`
`Type`	`project`
`ValidUntil`	`project`
`Name`	`extend`
`UPNSuffix`	`extend`
`timestamp`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

TI map Domain entity to EmailEvents

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: `EmailEvents_`

Let binding: `SenderDomains`

Let binding: `RecipientDomains`

Let binding: `TI`

union (2 sources)

Leg 1: `TI`

Leg 2: `TI`

Applied to the combined result

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

TI map Domain entity to EmailEvents

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: EmailEvents_

Let binding: SenderDomains

Let binding: RecipientDomains

Let binding: TI

union (2 sources)

Leg 1: TI

Leg 2: TI

Applied to the combined result

Exclusions

Indicators

Output fields

Let binding: `EmailEvents_`

Let binding: `SenderDomains`

Let binding: `RecipientDomains`

Let binding: `TI`

Leg 1: `TI`

Leg 2: `TI`