TI map Domain entity to Dns Events (ASIM DNS Schema)

Severity: medium
Time window: 14d
Group by: DnsQuery, DomainName, IndicatorId
Source: github.com/Azure/Azure-Sentinel

Identifies a match in DNS events from any Domain IOC from TI This analytic rule uses ASIM and supports any built-in or custom source that supports the ASIM DNS schema'

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1071` Application Layer Protocol

Rule body kusto

id: 999e9f5d-db4a-4b07-a206-29c4e667b7e8
name: TI map Domain entity to Dns Events (ASIM DNS Schema)
description: |
  Identifies a match in DNS events from any Domain IOC from TI
  This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM DNS schema'
severity: Medium
requiredDataConnectors:
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: DNS
    dataTypes:
      - DnsEvents
  - connectorId: AzureFirewall
    dataTypes: 
      - AzureDiagnostics
  - connectorId: Zscaler
    dataTypes:
      - CommonSecurityLog
  - connectorId: InfobloxNIOS
    dataTypes: 
      - Syslog
  - connectorId: GCPDNSDataConnector
    dataTypes: 
      - GCP_DNS_CL
  - connectorId: NXLogDnsLogs
    dataTypes: 
      - NXLog_DNS_Server_CL
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: CiscoUmbrellaDataConnector
    dataTypes: 
      - Cisco_Umbrella_dns_CL
  - connectorId: Corelight
    dataTypes: 
      - Corelight_CL
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
tags:
  - Id: 85aca4d1-5d15-4001-abd9-acb86ca1786a
    version: 1.0.0
  - Schema: ASIMDns
    SchemaVersion: 0.1.1
query: |
  let HAS_ANY_MAX = 10000;
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let DomainTIs= ThreatIntelligenceIndicator
    // Picking up only IOC's that contain the entities we want
    | where isnotempty(DomainName)
    | where TimeGenerated >= ago(ioc_lookBack)
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now();
  let Domains = DomainTIs | where isnotempty(DomainName) |summarize NDomains=dcount(DomainName), DomainsList=make_set(DomainName) 
    | project DomainList = iff(NDomains > HAS_ANY_MAX, dynamic([]), DomainsList) ;
  DomainTIs
    | join (
        _Im_Dns(starttime=ago(dt_lookBack), domain_has_any=toscalar(Domains))
        | extend DNS_TimeGenerated = TimeGenerated
  ) on $left.DomainName==$right.DnsQuery
  | where DNS_TimeGenerated < ExpirationDateTime
  | project LatestIndicatorTime, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, DNS_TimeGenerated, Dvc, SrcIpAddr, Domain, DnsQuery, DnsQueryType
  | extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Dvc
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: HostNameDomain
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SrcIpAddr
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url
  - entityType: DNS
    fieldMappings:
      - identifier: DomainName
        columnName: Domain        
customDetails:
  LatestIndicatorTime: LatestIndicatorTime
  Description: Description
  ActivityGroupNames: ActivityGroupNames
  IndicatorId: IndicatorId
  ThreatType: ThreatType
  ExpirationDateTime: ExpirationDateTime
  ConfidenceScore: ConfidenceScore
  DNSRequestTime: DNS_TimeGenerated
  SourceIPAddress: SrcIpAddr
  DnsQuery: DnsQuery
  QueryType: DnsQueryType
version: 1.1.8
kind: Scheduled

Stages and Predicates

Parameters

let HAS_ANY_MAX = 10000;
let dt_lookBack = 1h;
let ioc_lookBack = 14d;

Let binding: `Domains`

let Domains = DomainTIs | where isnotempty(DomainName) |summarize NDomains=dcount(DomainName), DomainsList=make_set(DomainName) 
  | project DomainList = iff(NDomains > HAS_ANY_MAX, dynamic([]), DomainsList);

Derived from HAS_ANY_MAX, DomainTIs.

The stages below define let DomainTIs (the rule's main pipeline source).

Stage 1: `source`

ThreatIntelligenceIndicator

Stage 2: `where`

| where isnotempty(DomainName)

Stage 3: `where`

| where TimeGenerated >= ago(ioc_lookBack)

Stage 4: `summarize`

| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId

Stage 5: `where`

| where Active == true and ExpirationDateTime > now()

The stages below run on DomainTIs (the outer pipeline).

Stage 6: `join`

DomainTIs
| join (
      _Im_Dns(starttime=ago(dt_lookBack), domain_has_any=toscalar(Domains))
      | extend DNS_TimeGenerated = TimeGenerated
) on $left.DomainName==$right.DnsQuery

Stage 7: `where`

| where DNS_TimeGenerated < ExpirationDateTime

Stage 8: `project`

| project LatestIndicatorTime, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, DNS_TimeGenerated, Dvc, SrcIpAddr, Domain, DnsQuery, DnsQueryType

Stage 9: `extend`

| extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))

Stage 10: `extend`

| extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)

HostNameDomain =

ifDomainIndex != -1substring(Dvc, (DomainIndex + 1))

elseDvc

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	`true` transforms: `cased`
`DNS_TimeGenerated`	lt	`ExpirationDateTime` transforms: `cased`
`DomainName`	is_not_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`
`ConfidenceScore`	`project`
`DNS_TimeGenerated`	`project`
`Description`	`project`
`DnsQuery`	`project`
`DnsQueryType`	`project`
`Domain`	`project`
`Dvc`	`project`
`ExpirationDateTime`	`project`
`IndicatorId`	`project`
`LatestIndicatorTime`	`project`
`SrcIpAddr`	`project`
`ThreatType`	`project`
`Url`	`project`
`DomainIndex`	`extend`
`HostName`	`extend`
`HostNameDomain`	`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 Dns Events (ASIM DNS Schema)

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: `Domains`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `summarize`

Stage 5: `where`

Stage 6: `join`

Stage 7: `where`

Stage 8: `project`

Stage 9: `extend`

Stage 10: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

TI map Domain entity to Dns Events (ASIM DNS Schema)

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: Domains

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: summarize

Stage 5: where

Stage 6: join

Stage 7: where

Stage 8: project

Stage 9: extend

Stage 10: extend

Indicators

Output fields

Let binding: `Domains`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `summarize`

Stage 5: `where`

Stage 6: `join`

Stage 7: `where`

Stage 8: `project`

Stage 9: `extend`

Stage 10: `extend`