Windows Regsvr32.exe Initiated Network Connection
Flags outbound network connections initiated by Regsvr32.exe based on process image and connection initiation telemetry.
FreeReviewedSigma · Medium · v2
- Product
- windows
- Category
- network_connection
- Author
- Dmitriy Lifanov, oscd.community (SigmaHQ), DRL 1.1
- Published
- 2019-10-25
- Updated
- 2026-07-31
ATT&CK techniques
Execution → Defense EvasionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule flags when a network connection is initiated by regsvr32.exe on Windows. Attackers may abuse regsvr32 for stealthy execution paths that involve outbound network activity. It relies on network connection telemetry that records the initiating process image name ending with \regsvr32.exe and an initiated connection indicator.
Reporting behind it
- pentestlab.bloghttps://pentestlab.blog/2017/05/11/applocker-bypass-regsvr32/
- oddvar.moehttps://oddvar.moe/2017/12/13/applocker-case-study-how-insecure-is-it-really-part-1/
- github.comhttps://github.com/SigmaHQ/sigma/blob/master/rules/windows/network_connection/net_connection_win_regsvr32_network_activity.yml
Changelog
v2- v2Candidate ingested via manual entry.2026-07-31
- v1No changelog recorded for this version.2026-07-30
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
windows-regsvr32-exe-initiated-network-connection-c7e91a02
title: Windows Regsvr32.exe Initiated Network Connection
id: 5895235f-bc4b-47a6-9b2c-9ee50acbfcd4
status: test
description: This rule flags when a network connection is initiated by regsvr32.exe on Windows. Attackers may abuse regsvr32 for stealthy execution paths that involve outbound network activity. It relies on network connection telemetry that records the initiating process image name ending with \regsvr32.exe and an initiated connection indicator.
references:
- https://pentestlab.blog/2017/05/11/applocker-bypass-regsvr32/
- https://oddvar.moe/2017/12/13/applocker-case-study-how-insecure-is-it-really-part-1/
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/network_connection/net_connection_win_regsvr32_network_activity.yml
author: Dmitriy Lifanov, oscd.community, Huntrule Team
date: 2019-10-25
modified: 2023-09-18
tags:
- attack.execution
- attack.stealth
- attack.t1559.001
- attack.t1218.010
logsource:
category: network_connection
product: windows
detection:
selection:
Initiated: "true"
Image|endswith: \regsvr32.exe
condition: selection
falsepositives:
- Unknown
level: medium
license: DRL-1.1
related:
- id: c7e91a02-d771-4a6d-a700-42587e0b1095
type: derived