Detection rules › Kusto
GreyNoise TI Map IP Entity to DnsEvents
This query maps any IP indicators of compromise (IOCs) from GreyNoise Threat Intelligence (TI), by searching for matches in DnsEvents.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1071 Application Layer Protocol |
Rule body kusto
id: ddf47b6f-870c-5712-a296-1383acb13c82
name: GreyNoise TI Map IP Entity to DnsEvents
version: 1.0.2
kind: Scheduled
description: |
This query maps any IP indicators of compromise (IOCs) from GreyNoise Threat Intelligence (TI), by searching for matches in DnsEvents.
severity: Medium
requiredDataConnectors:
- connectorId: ThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: DNS
dataTypes:
- DnsEvents
- connectorId: ASimDnsActivityLogs
dataTypes:
- DnsEvents
- connectorId: GreyNoise2SentinelAPI
dataTypes:
- ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
- CommandAndControl
relevantTechniques:
- T1071
query: |
let dt_lookBack = 1h; // Look back 1 hour for DNS events
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
// Fetch threat intelligence indicators related to IP addresses
let IP_Indicators = ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| where SourceSystem == 'GreyNoise'
| where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
| extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
| where ipv4_is_private(TI_ipEntity) == false and TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127.";
// Perform a join between IP indicators and DNS events
IP_Indicators
// Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
| join kind=innerunique (
DnsEvents
| where TimeGenerated >= ago(dt_lookBack)
| where SubType =~ "LookupQuery" and isnotempty(IPAddresses)
| mv-expand SingleIP = split(IPAddresses, ", ") to typeof(string)
| extend DNS_TimeGenerated = TimeGenerated
)
on $left.TI_ipEntity == $right.SingleIP
// Filter out DNS events that occurred after the expiration of the corresponding indicator
| where DNS_TimeGenerated < ExpirationDateTime
// Group the results by IndicatorId and SingleIP, and keep the DNS event with the latest timestamp
| summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, SingleIP
// Select the desired output fields
| project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, DomainName, ExpirationDateTime, ConfidenceScore,
TI_ipEntity, Computer, EventId, SubType, ClientIP, Name, IPAddresses, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
| extend timestamp = DNS_TimeGenerated, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
entityMappings:
- entityType: Host
fieldMappings:
- identifier: HostName
columnName: HostName
- identifier: DnsDomain
columnName: DnsDomain
- entityType: IP
fieldMappings:
- identifier: Address
columnName: ClientIP
- entityType: URL
fieldMappings:
- identifier: Url
columnName: Url
Stages and Predicates
Parameters
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
The stages below define let IP_Indicators (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: where
| where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
Stage 7: extend (3 consecutive steps)
| extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
TI_ipEntity =isnotempty(NetworkIP)NetworkIPNetworkDestinationIPStage 8: where
| where ipv4_is_private(TI_ipEntity) == false and TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127."
The stages below run on IP_Indicators (the outer pipeline).
Stage 9: join
IP_Indicators
| join kind=innerunique (
DnsEvents
| where TimeGenerated >= ago(dt_lookBack)
| where SubType =~ "LookupQuery" and isnotempty(IPAddresses)
| mv-expand SingleIP = split(IPAddresses, ", ") to typeof(string)
| extend DNS_TimeGenerated = TimeGenerated
)
on $left.TI_ipEntity == $right.SingleIP
Stage 10: where
| where DNS_TimeGenerated < ExpirationDateTime
Stage 11: summarize
| summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, SingleIP
Stage 12: project
| project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, DomainName, ExpirationDateTime, ConfidenceScore,
TI_ipEntity, Computer, EventId, SubType, ClientIP, Name, IPAddresses, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
Stage 13: extend
| extend timestamp = DNS_TimeGenerated, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
TI_ipEntity | cidr_match | 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 169.254.0.0/16, 127.0.0.0/8 |
TI_ipEntity | starts_with | 127. |
TI_ipEntity | starts_with | :: |
TI_ipEntity | starts_with | fe80 |
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 |
|
DNS_TimeGenerated | lt |
|
EmailSourceIpAddress | is_not_null | |
IPAddresses | is_not_null | |
NetworkDestinationIP | is_not_null | |
NetworkIP | is_not_null | |
NetworkSourceIP | is_not_null | |
SourceSystem | eq |
|
SubType | eq |
|
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 |
ClientIP | project |
Computer | project |
ConfidenceScore | project |
DNS_TimeGenerated | project |
Description | project |
DomainName | project |
EmailSourceIpAddress | project |
EventId | project |
ExpirationDateTime | project |
IPAddresses | project |
IndicatorId | project |
Name | project |
NetworkDestinationIP | project |
NetworkIP | project |
NetworkSourceIP | project |
SubType | project |
TI_ipEntity | project |
ThreatType | project |
Type | project |
Url | project |
DnsDomain | extend |
HostName | extend |
timestamp | extend |