Windows Security: Remote DCOM IE DLL Hijack via iertutil.dll in Internet Explorer path

Flags network file writes of iertutil.dll under IE’s Program Files path associated with potential DCOM DLL hijacking.

FreeReviewedSigma · High · v2

Product: windows
Service: security
Author: Roberto Rodriguez @Cyb3rWard0g, Open Threat Research (OTR) (SigmaHQ), DRL 1.1
Published: 2020-10-12
Updated: 2026-07-31

ATT&CK techniques

Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
- T1021.002SMB/Windows Admin Shares
- T1021.003Distributed Component Object Model
Collection
C2
Exfiltration
Impact

What it detects

This rule flags network activity where a file named iertutil.dll is created in C:\Program Files\Internet Explorer\, matching a common DLL hijack target for a DCOM InternetExplorer scenario. Attackers may use this to load a malicious DLL in place of a legitimate component and gain code execution. It relies on Windows Security auditing event 5145 and inspects the RelativeTargetName ending with the targeted DLL path, excluding machine accounts that end with '$'.

Reporting behind it

Related detections9 linkedT1021.002 — drag to rearrange

Windows DCOM InternetExplorer.Application iertutil.dll DLL Hijack Suspicion

Windows DCOM InternetExplorer.Application DLL Hijack via iertutil.dll Image Load

Suspicious Access to Citrix Session Evidence Registry Keys

Suspicious Ransomware Fan-Out Deployment via PsExec Spread (Qilin)

Suspicious Impacket smbexec Command Execution Pattern

Malicious Impacket Wmiexec Remote Command Execution Pattern

Suspicious Remote Admin Share Execution via Conhost

Malicious Network Share Manipulation via Commandline (via process_creation)

Suspicious Number of Oustanding SMB Requests Increased (via process_creation)

Windows Security: Remote DCOM IE DLL Hijack via iertutil.dll in Internet Explorer path

Pivot detection · T1021.002 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No 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-security-remote-dcom-ie-iertutil-dll-dll-hijack-via-network-file-write-5-c39f0c81

title: "Windows Security: Remote DCOM IE DLL Hijack via iertutil.dll in Internet Explorer path"
id: 8e16e159-fd6c-4edd-a342-84a7dbbe36fa
status: test
description: This rule flags network activity where a file named iertutil.dll is created in C:\Program Files\Internet Explorer\, matching a common DLL hijack target for a DCOM InternetExplorer scenario. Attackers may use this to load a malicious DLL in place of a legitimate component and gain code execution. It relies on Windows Security auditing event 5145 and inspects the RelativeTargetName ending with the targeted DLL path, excluding machine accounts that end with '$'.
references:
  - https://threathunterplaybook.com/hunts/windows/201009-RemoteDCOMIErtUtilDLLHijack/notebook.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_dcom_iertutil_dll_hijack.yml
author: Roberto Rodriguez @Cyb3rWard0g, Open Threat Research (OTR), Huntrule Team
date: 2020-10-12
modified: 2022-11-26
tags:
  - attack.lateral-movement
  - attack.t1021.002
  - attack.t1021.003
logsource:
  product: windows
  service: security
detection:
  selection:
    EventID: 5145
    RelativeTargetName|endswith: \Internet Explorer\iertutil.dll
  filter:
    SubjectUserName|endswith: $
  condition: selection and not filter
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: c39f0c81-7348-4965-ab27-2fde35a1b641
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

SplunkSPL