Description
This detection looks for cases of close-time proximity between incoming network traffic on RPC/TCP, followed by the creation of a DCOM object, followed by the creation of a child process of the DCOM object.
The query first identifies incoming network traffic over RPC/TCP, followed by the creation of a DCOM object (process) within 2 seconds, followed by the creation of a child process of this DCOM object.
- Type de règle
- Scheduled
- Version
- 1.0.0
- Statut déclaré
- Available
- Fréquence
- 1h
- Période analysée
- 1h
- Déclenchement
- gt 0
Couverture MITRE déclarée
Sources déclarées
Métadonnées du fichier source. Aucune dépendance déduite du KQL.
Connecteurs
Types de données
Requête KQL
Requête originale, sans modification.
let allowListedExecs = dynamic(["TiWorker.exe", "dllhost.exe", "backgroundTaskHost.exe", "mobsync.exe", "WmiPrvSE.exe", "RuntimeBroker.exe", "smartscreen.exe", "SppExtComObj.Exe", "usocoreworker.exe", "browser_broker.exe", "ssoncom.exe"]);
let rpcNetwEvents = materialize(DeviceNetworkEvents
| where InitiatingProcessFileName =~ "svchost.exe" and InitiatingProcessCommandLine has "rpcss" and LocalPort == 135
| where LocalIP !~ RemoteIP and ActionType != "ListeningConnectionCreated"
| project TimestampNetwEvent=bin(Timestamp, 5s),TimestampNetwEventExact=Timestamp, DeviceId, DeviceName, RPCHostID=InitiatingProcessId, RPCHostFileName=InitiatingProcessFileName, LocalIP, RemoteIP);
let dcomProcEvents = materialize (DeviceProcessEvents
| where InitiatingProcessFileName =~ "svchost.exe" and InitiatingProcessCommandLine has "dcomlaunch"
| project TimestampProcEvent=bin(Timestamp, 5s),TimestampProcEventExact=Timestamp, DeviceId, DeviceName, DCOMHostPID=InitiatingProcessId, DCOMHostFileName=InitiatingProcessFileName, DCOMPID=ProcessId, DCOMFileName=FileName, DCOMCmdLine=ProcessCommandLine);
let lastBootTime = materialize(DeviceProcessEvents
| where FileName =~ "services.exe"
| summarize LastBootTime=max(Timestamp) by DeviceId);
let RemoteDcomProcs = materialize(rpcNetwEvents
| join kind=inner dcomProcEvents on DeviceId
| join kind=leftouter lastBootTime on DeviceId
| where TimestampProcEvent > LastBootTime+5m // Ignore first 5 min after boot.
// Avoiding < 2 since if the time between netw and proc creation is negative, they can't be related. Network event must come first.
| where datetime_diff("second", TimestampProcEventExact, TimestampNetwEventExact) between (0 .. 2)
// Allow-listing some usual suspects which create lot of noise. This is dangerous though...huge gap for bypass.
| where DCOMFileName !in~ (allowListedExecs));
RemoteDcomProcs
| join kind=inner hint.strategy=broadcast (
DeviceProcessEvents
| where InitiatingProcessParentFileName =~ "svchost.exe" and InitiatingProcessFileName in ((RemoteDcomProcs | project DCOMFileName)))
on $left.DCOMHostPID == $right.InitiatingProcessParentId, DeviceId, $left.DCOMPID == $right.InitiatingProcessId
| where InitiatingProcessParentFileName =~ "svchost.exe" and InitiatingProcessFileName =~ DCOMFileName
// Allow-listing the magic of Defender.
| where FileName !in~ ("csc.exe")
| summarize make_set(ProcessCommandLine) by TimestampNetwEventExact, TimestampProcEventExact, DeviceId, DeviceName, InitiatingProcessId, LocalIP, RemoteIP, LastBootTime, DCOMCmdLine
Entités déclarées
Contenus associés
Liens établis à partir des identifiants déclarés et des manifests des solutions.
Traçabilité de la source
GitHubLes valeurs affichées proviennent des fichiers du dépôt Azure/Azure-Sentinel. Elles décrivent le modèle publié, pas la configuration de votre workspace.
- Commit
7ca9800↗- Identifiant source
d58035ff-0bac-4c61-a7f4-f58939ff9764
GSTEP / SUIVI DU CATALOGUE
Ajouté au catalogue : 16 sept. 2026 · 05:49 UTC
Dernier changement observé : 16 sept. 2026 · 05:49 UTC