Suspicious DotNet Utility MSBuild RegAsm RegSvcs Network Beacon Indicating Hollowing

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 MSBuild.exe, RegAsm.exe or RegSvcs.exe making an external network connection, the process hollowing targets used by Blind Eagle to run Remcos and njRAT with command and control over dynamic DNS. These .NET utilities have no reason to beacon outbound, so an external connection reveals injected remote access malware.

Reporting behind it

Related detections9 linkedT1055.012 — drag to rearrange

Suspicious .NET Utility Spawned by Script Host for Process Hollowing

Suspicious MSBuild Spawned by PowerShell (via process_creation)

Suspicious RegSvcs Execution Spawned by Script Interpreter for Process Hollowing (via process_creation)

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 DotNet Utility MSBuild RegAsm RegSvcs Network Beacon Indicating Hollowing

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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