Microsoft Sentinel medium experimental kql

TI Map Domain Entity to DeviceNetworkEvents

'This query identifies any Domain indicators of compromise (IOCs) from threat intelligence (TI) by searching for matches in DeviceNetworkEvents.'

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Detection Logic

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let DeviceNetworkEvents_ = DeviceNetworkEvents
| where isnotempty(RemoteUrl)
| where TimeGenerated >= ago(dt_lookBack)
| where ActionType !has "ConnectionFailed"
| extend Domain = tostring(parse_url(tolower(RemoteUrl)).Host)
| where isnotempty(Domain)
| project-rename DeviceNetworkEvents_TimeGenerated = TimeGenerated;
let DeviceNetworkEventDomains = DeviceNetworkEvents_
| distinct Domain
| summarize make_list(Domain);
ThreatIntelIndicators
| extend IndicatorType = replace(@"\[
| \]
| \""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "domain-name"
| extend DomainName = tolower(ObservableValue)
| where TimeGenerated >= ago(ioc_lookBack)
| extend IndicatorId = tostring(split(Id, "--")[2])
| where DomainName in (DeviceNetworkEventDomains)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
| extend Description = tostring(parse_json(Data).description)
| extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
| where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;"
| project-reorder *, IsActive, Tags, TrafficLightProtocolLevel, DomainName, Type
| join kind=innerunique (DeviceNetworkEvents_) on $left.DomainName == $right.Domain
| where DeviceNetworkEvents_TimeGenerated < ValidUntil
| summarize DeviceNetworkEvents_TimeGenerated = arg_max(DeviceNetworkEvents_TimeGenerated, *) by IndicatorId
| project DeviceNetworkEvents_TimeGenerated, IndicatorId, Url = RemoteUrl, Confidence, Description, Tags, TrafficLightProtocolLevel, ActionType, DeviceId, DeviceName, InitiatingProcessAccountUpn, InitiatingProcessCommandLine, RemoteIP, RemotePort
| extend Name = tostring(split(InitiatingProcessAccountUpn, '@', 0)[0]), UPNSuffix = tostring(split(InitiatingProcessAccountUpn, '@', 1)[0])
| extend timestamp = DeviceNetworkEvents_TimeGenerated, UserPrincipalName = InitiatingProcessAccountUpn

Field Validations

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