Suspicious Download LOLBIN Spawned by ScreenConnect Client

ATT&CK techniques

C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule detects the ScreenConnect client service spawning download utilities such as bitsadmin or PowerShell which is the payload retrieval chain that dropped KrustyLoader after a ScreenConnect exploit as described by WithSecure. Remote monitoring tools launching download LOLBINs shortly after exploitation frequently indicates ingress tool transfer of a second stage.

Reporting behind it

Related detections9 linkedT1105 — drag to rearrange

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Suspicious WebDAV Retrieval via rundll32 and davclnt.dll (via process_creation)

Suspicious PowerShell Download to Temp and In-Memory Execution via IEX (via process_creation)

Suspicious PowerShell Download of Bumblebee Stager Files (via process_creation)

Suspicious Download LOLBIN Spawned by ScreenConnect Client

Pivot detection · T1105 · 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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