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

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1036.008Masquerade File Type
- T1218.011Rundll32
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects regsvr32 or rundll32 loading a module that carries a disguised or non-standard extension such as .dat, .tmp, .png or .log from a user-writable directory, a masquerading pattern used by loaders like Qbot to hide their DLL payload. Proxy execution of renamed DLLs is documented in the Red Canary Threat Detection Report as a way to defeat extension-based controls. Detecting these disguised module loads surfaces the payload execution.

Reporting behind it

Related detections9 linkedT1218.011 — drag to rearrange

Suspicious Rundll32 Loading DLL From Public or ProgramData Path via Process Creation (via process_creation)

Malicious LSASS Credential Dump via Rundll32 Comsvcs MiniDump via Process Creation (via process_creation)

Suspicious Rundll32 Execution Without a DLL Reference via Process Creation (via process_creation)

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

Suspicious Rundll32 Execution with Latrodectus Loader Exports (via process_creation)

Suspicious Rundll32 Execution with IcedID Loader Export (via process_creation)

Malicious Scheduled Task Running rundll32 w32analytics (via process_creation)

Suspicious StrelaStealer DLL Execution via Rundll32 Hello Export from Temp (via process_creation)

Malicious Scheduled rundll32 Execution of ProgramData VMware DLL by BianLian

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

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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