In-Memory XWorm Injection Target RegAsm Spawned from User AppData (via process_creation)

ATT&CK techniques

Priv Esc → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
- T1055.012Process Hollowing
Defense Evasion
- T1055.012Process Hollowing
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects RegAsm.exe launched from a process residing in a user AppData or Temp directory, the PE-hollowing pattern used by the Noodlophile campaign to inject XWorm into a trusted .NET utility. Adversaries leverage RegAsm as a signed developer binary and hollow it in memory so the RAT runs under a Microsoft-signed process, making early detection critical for exposing the injection before remote access is established.

Reporting behind it

Related detections9 linkedT1055.012 — drag to rearrange

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Suspicious MSBuild Execution Spawned by PowerShell via PhantomVAI Loader (via process_creation)

Suspicious Rundll32 Loading Non-DLL Image Extension File

Suspicious MSBuild Execution Spawned by Command Shell for Process Hollowing (via process_creation)

Malicious Desktop Window Manager Impersonation From Non-System Path via process_creation

Suspicious .NET Utility Spawned by AutoHotkey Loader for Process Hollowing (via process_creation)

Suspicious csc.exe Spawned by Document Reader for Process Injection

Suspicious RegAsm Execution Spawned by Script Host for Process Hollowing (via process_creation)

Suspicious .NET Utility Launched as Process Injection Target (via process_creation)

In-Memory XWorm Injection Target RegAsm Spawned from User AppData (via process_creation)

Pivot detection · T1055.012 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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