DLL Side-Loading via Signed Binary Loading Known Malicious Helper DLL

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1574.001DLL
Persistence
- T1574.001DLL
Priv Esc
- T1574.001DLL
Defense Evasion
- T1574.001DLL
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects trusted signed executables side-loading helper DLLs commonly abused for DLL search-order hijacking such as GUP.exe loading libcurl.dll or MsMpEng.exe loading mpsvc.dll. This technique was widely abused by PlugX and related tooling to run malicious code under the guise of a legitimate signed process, and the rule filters the legitimate Windows Defender load path.

Reporting behind it

Related detections9 linkedT1574.001 — drag to rearrange

Suspicious msimg32.dll Loaded from Non-System Directory

Suspicious DLL Sideloading via msdtc oci.dll Install (via process_creation)

Suspicious wmicodegen.dll Sideload by inetinfo.exe (UAT-8099 Cobalt Strike)

Suspicious LucidRook DismCore.dll Side-Load into Browser Process

Suspicious Encrypted Implant File Creation for DLL Search Order Hijacking (RainyDay Turian PlugX)

Suspicious RoboForm Signed Binary Executed From Non-Standard Path (via process_creation)

Malicious dal_keepalives.dll Sideloaded By Signed Binary (via image_load)

Suspicious Cortex XDR Binary Sideloading winutils.dll (via image_load)

Suspicious CoinLoader DLL Sideload From Z-1-36-81 Directory (via image_load)

DLL Side-Loading via Signed Binary Loading Known Malicious Helper DLL

Pivot detection · T1574.001 · 9 related

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

Full detection rule

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