Suspicious rundll32 Loading DLL from AppData via DllRegisterServer

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218.011Rundll32
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects rundll32 executing a DLL located under AppData through the DllRegisterServer entry point. OysterLoader stages its COPYING3.dll payload in the roaming profile and runs it with this export. Running an AppData resident DLL through rundll32 with DllRegisterServer is a recognised loader execution pattern.

Reporting behind it

Related detections9 linkedT1218.011 — drag to rearrange

Malicious Rundll32 Loading an Export From a User Path (via process_creation)

Renamed Regsvr32 or Rundll32 Loading a DLL With a Non-Standard Extension (via process_creation)

Malicious Rundll32 DllRegisterServer Execution From a User-Writable Path (via process_creation)

IMEEX Framework DLL Execution via Rundll32 Loading imaadp (via process_creation)

Suspicious Persistence via pcalua Launching rundll32 Control_RunDLL

Suspicious Rundll32 Executing DLL Start Export With Control Flags

Suspicious Rundll32 Execution of Timestamp-Named DLL

Suspicious Rundll32 Loading DLL from LocalAppData with Short Export (via process_creation)

Malicious Word Spawning Rundll32 Loading DLL from Roaming Word Folder

Suspicious rundll32 Loading DLL from AppData via DllRegisterServer

Pivot detection · T1218.011 · 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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