GreyNoise TI map IP entity to Network Session Events (ASIM Network Session schema)

Status: available
Severity: medium
Time window: 14d
Group by: IndicatorId, IoCIP, TI_ipEntity
Source: github.com/Azure/Azure-Sentinel

'This rule identifies a match Network Sessions for which the source or destination IP address is a known GreyNoise IoC. This analytic rule uses ASIM and supports any built-in or custom source that supports the ASIM NetworkSession schema'

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1071` Application Layer Protocol

Rule body kusto

id: 536e8e5c-ce0e-575e-bcc9-aba8e7bf9316
name: GreyNoise TI map IP entity to Network Session Events (ASIM Network Session schema)
version: 1.0.3
kind: Scheduled
description: |
  'This rule identifies a match Network Sessions for which the source or destination IP address is a known GreyNoise IoC.
  This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM NetworkSession schema'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: AWSS3
    dataTypes:
      - AWSVPCFlow
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - DeviceNetworkEvents
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsSecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsForwardedEvents
    dataTypes:
      - WindowsEvent
  - connectorId: Zscaler
    dataTypes:
      - CommonSecurityLog
  - connectorId: MicrosoftSysmonForLinux
    dataTypes:
      - Syslog
  - connectorId: PaloAltoNetworks
    dataTypes:
      - CommonSecurityLog
  - connectorId: AzureMonitor(VMInsights)
    dataTypes:
      - VMConnection
  - connectorId: AzureFirewall
    dataTypes:
      - AzureDiagnostics
  - connectorId: AzureNSG
    dataTypes:
      - AzureDiagnostics
  - connectorId: CiscoASA
    dataTypes:
      - CommonSecurityLog
  - connectorId: CiscoAsaAma
    dataTypes:
      - CommonSecurityLog
  - connectorId: Corelight
    dataTypes:
      - Corelight_CL
  - connectorId: AIVectraStream
    dataTypes:
      - VectraStream
  - connectorId: CheckPoint
    dataTypes:
      - CommonSecurityLog
  - connectorId: Fortinet
    dataTypes:
      - CommonSecurityLog
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: CiscoMeraki
    dataTypes:
      - Syslog
      - CiscoMerakiNativePoller
  - connectorId: GreyNoise2SentinelAPI
    dataTypes:
      - ThreatIntelligenceIndicator

queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let IP_TI = materialize (
  ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()
  | where SourceSystem == 'GreyNoise'
    | extend TI_ipEntity = coalesce(NetworkIP, NetworkDestinationIP, NetworkSourceIP,EmailSourceIpAddress,"NO_IP")
    | where TI_ipEntity != "NO_IP"
  );
  IP_TI
    // using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
  | join kind=innerunique 
  (
    _Im_NetworkSession (starttime=ago(dt_lookBack))
    | where isnotempty(SrcIpAddr)
    | summarize imNWS_mintime=min(TimeGenerated), imNWS_maxtime=max(TimeGenerated) by SrcIpAddr, DstIpAddr, Dvc, EventProduct, EventVendor  
    | lookup (IP_TI | project TI_ipEntity, Active) on $left.SrcIpAddr == $right.TI_ipEntity
    | project-rename SrcMatch = Active
    | lookup (IP_TI | project TI_ipEntity, Active) on $left.DstIpAddr == $right.TI_ipEntity
    | project-rename DstMatch = Active
    | where SrcMatch or DstMatch
    | extend 
        IoCIP = iff(SrcMatch, SrcIpAddr, DstIpAddr),
        IoCDirection = iff(SrcMatch, "Source", "Destination")
  )on $left.TI_ipEntity == $right.IoCIP
  | where imNWS_mintime < ExpirationDateTime
  | project imNWS_mintime, imNWS_maxtime, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, SrcIpAddr, DstIpAddr, IoCDirection, IoCIP, Dvc, EventVendor, EventProduct
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IoCIP

customDetails:
  EventStartTime: imNWS_mintime
  EventEndTime: imNWS_maxtime
  IoCDescription: Description
  ActivityGroupNames: ActivityGroupNames
  IndicatorId: IndicatorId
  ThreatType: ThreatType
  IoCExpirationTime: ExpirationDateTime
  IoCConfidenceScore: ConfidenceScore
  IoCIPDirection: IoCDirection

alertDetailsOverride:
  alertDisplayNameFormat: A network session {{IoCDirection}} address {{IoCIP}} matched an IoC. 
  alertDescriptionFormat: The {{IoCDirection}} address {{IoCIP}} of a network session  matched a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence blead for more information on the indicator.

tags:
  - Schema: ASIMNetworkSession
    SchemaVersion: 0.2.4

Stages and Predicates

Parameters

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

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

Stage 1: `source`

ThreatIntelligenceIndicator

Stage 2: `where`

| where TimeGenerated >= ago(ioc_lookBack)

Stage 3: `summarize`

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

Stage 4: `where`

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

Stage 5: `where`

| where SourceSystem == 'GreyNoise'

Stage 6: `extend`

| extend TI_ipEntity = coalesce(NetworkIP, NetworkDestinationIP, NetworkSourceIP,EmailSourceIpAddress,"NO_IP")

Stage 7: `where`

| where TI_ipEntity != "NO_IP"

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

Stage 8: `join`

IP_TI
| join kind=innerunique 
(
  _Im_NetworkSession (starttime=ago(dt_lookBack))
  | where isnotempty(SrcIpAddr)
  | summarize imNWS_mintime=min(TimeGenerated), imNWS_maxtime=max(TimeGenerated) by SrcIpAddr, DstIpAddr, Dvc, EventProduct, EventVendor  
  | lookup (IP_TI | project TI_ipEntity, Active) on $left.SrcIpAddr == $right.TI_ipEntity
  | project-rename SrcMatch = Active
  | lookup (IP_TI | project TI_ipEntity, Active) on $left.DstIpAddr == $right.TI_ipEntity
  | project-rename DstMatch = Active
  | where SrcMatch or DstMatch
  | extend 
      IoCIP = iff(SrcMatch, SrcIpAddr, DstIpAddr),
      IoCDirection = iff(SrcMatch, "Source", "Destination")
)on $left.TI_ipEntity == $right.IoCIP

Stage 9: `where`

| where imNWS_mintime < ExpirationDateTime

Stage 10: `project`

| project imNWS_mintime, imNWS_maxtime, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, SrcIpAddr, DstIpAddr, IoCDirection, IoCIP, Dvc, EventVendor, EventProduct

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`
`SourceSystem`	eq	`GreyNoise` transforms: `cased`
`SrcIpAddr`	is_not_null	(no value, null check)
`TI_ipEntity`	ne	`NO_IP` transforms: `cased`
`imNWS_mintime`	lt	`ExpirationDateTime` transforms: `cased`

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`
`Description`	`project`
`DstIpAddr`	`project`
`Dvc`	`project`
`EventProduct`	`project`
`EventVendor`	`project`
`ExpirationDateTime`	`project`
`IndicatorId`	`project`
`IoCDirection`	`project`
`IoCIP`	`project`
`SrcIpAddr`	`project`
`ThreatType`	`project`
`imNWS_maxtime`	`project`
`imNWS_mintime`	`project`

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`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)

GreyNoise TI map IP entity to Network Session Events (ASIM Network Session schema)

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `summarize`

Stage 4: `where`

Stage 5: `where`

Stage 6: `extend`

Stage 7: `where`

Stage 8: `join`

Stage 9: `where`

Stage 10: `project`

Indicators

Output fields

Keyboard shortcuts

Search operators

GreyNoise TI map IP entity to Network Session Events (ASIM Network Session schema)

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: summarize

Stage 4: where

Stage 5: where

Stage 6: extend

Stage 7: where

Stage 8: join

Stage 9: where

Stage 10: project

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `summarize`

Stage 4: `where`

Stage 5: `where`

Stage 6: `extend`

Stage 7: `where`

Stage 8: `join`

Stage 9: `where`

Stage 10: `project`