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

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 loading a DLL named settings.lock from the Microsoft MicrosoftOffice365Hub AppX package settings directory. This loader technique is used by the Xctdoor and XcLoader backdoors to execute encrypted payloads from a user AppX path where legitimate COM registration is not expected.

Reporting behind it

Related detections9 linkedT1218.010 — drag to rearrange

Suspicious Regsvr32 Execution of SafePay Loader DLL

Suspicious Scheduled Task Running Regsvr32 with Extreme Duration by StaryDobry

Malicious DynamicWrapperX Registration via regsvr32 (via process_creation)

Suspicious Run Key Persistence Executing regsvr32

Suspicious regsvr32 Registering DLL from User AppData

Malicious Regsvr32 Loading Masqueraded VPN DLL via Process Creation

Malicious Regsvr32 ShellExec_RunDLL Proxy Execution (via process_creation)

Suspicious DLL Execution via Regsvr32 DllInstall of dat File

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

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

Pivot detection · T1218.010 · 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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