Malicious regsvr32.exe Spawned by calc.exe via DLL Side-Loading

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218.010Regsvr32
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects regsvr32.exe launched with the Windows Calculator calc.exe as its parent process. During Qbot infections the side-loaded calc.exe uses regsvr32 to register and execute the trojan payload DLL. Calculator legitimately never spawns regsvr32, so this parent-child chain is a strong indicator of DLL side-loading and proxied code execution.

Reporting behind it

Related detections9 linkedT1218.010 — drag to rearrange

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Malicious Xctdoor XcLoader Execution via Regsvr32 AppX Path Abuse (via process_creation)

Malicious Office Application Loading a User-Path DLL via Regsvr32 or Rundll32 (via process_creation)

Masquerading SSLoad PhantomLoader DLL Execution via Regsvr32 Silent Load from AppData (via process_creation)

Malicious Kimsuky AlphaSeed Payload Execution via Regsvr32 Loading edge dat (via process_creation)

Malicious Regsvr32 Executing DLL From Windows Temp

HttpSpy Payload Registration via Regsvr32 of Non-DLL File (via process_creation)

Malicious regsvr32 Scriptlet Execution via scrobj.dll

Malicious regsvr32.exe Spawned by calc.exe via DLL Side-Loading

Pivot detection · T1218.010 · 9 related

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