huntrule

Windows regsvr32 Execution from Suspicious DLL Paths

Alerts on regsvr32 runs whose command line references a DLL in highly suspicious Windows directories.

FreeReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2023-05-26
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

Defense Evasion

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags Windows process executions of regsvr32 where the command line indicates the target DLL is located in uncommon or high-risk filesystem paths (e.g., Temp, system component subdirectories, or specific spool/Tasks/Tracing locations). Attackers often use regsvr32 to execute code indirectly through COM registration or DLL loading, making path context a useful signal for stealthy execution. The detection relies on process creation telemetry, matching regsvr32 via image/original filename and correlating command-line path substrings while excluding common legitimate directories.

Reporting behind it

Related detections9 linkedT1218.010 — drag to rearrange
Suspicious Script Host Spawning Regsvr32 via Strela Stealer JScript Loader (via process_creation)
Malicious DLL Registration via regsvr32 Loading prnfldr (via process_creation)
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)
Windows regsvr32 Execution from Suspicious DLL Paths
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.