Suspicious WINWORD.exe DLL loading via /l flag and .dll path on Windows
Flags WINWORD.exe runs that include /l and a .dll indicator, suggesting potential DLL sideloading on Windows.
- Product
- windows
- Category
- process_creation
- Author
- Victor Sergeev, oscd.community (SigmaHQ), DRL 1.1
- Published
- 2020-10-09
- Updated
- 2026-07-30
ATT&CK techniques
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 process creation events where WINWORD.exe is invoked with a command line containing the /l flag and a .dll reference, indicating potential DLL sideloading behavior. Attackers may use Office application loading mechanisms to execute attacker-controlled code stealthily through a malicious DLL. The detection relies on Windows process creation telemetry, specifically the executable path/name and the full command line content.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
title: Suspicious WINWORD.exe DLL loading via /l flag and .dll path on Windows
id: 64c8d3e3-6fc8-4338-ad75-957e579c21b6
related:
- id: 2621b3a6-3840-4810-ac14-a02426086171
type: obsolete
- id: f7375e28-5c14-432f-b8d1-1db26c832df3
type: derived
status: test
description: This rule flags process creation events where WINWORD.exe is invoked with a command line containing the /l flag and a .dll reference, indicating potential DLL sideloading behavior. Attackers may use Office application loading mechanisms to execute attacker-controlled code stealthily through a malicious DLL. The detection relies on Windows process creation telemetry, specifically the executable path/name and the full command line content.
references:
- https://github.com/D4Vinci/One-Lin3r/blob/9fdfa5f0b9c698dfbd4cdfe7d2473192777ae1c6/one_lin3r/core/liners/windows/cmd/dll_loader_word.py
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_office_winword_dll_load.yml
author: Victor Sergeev, oscd.community, Huntrule Team
date: 2020-10-09
modified: 2023-03-29
tags:
- attack.stealth
- attack.t1202
logsource:
category: process_creation
product: windows
detection:
selection_img:
- Image|endswith: \WINWORD.exe
- OriginalFileName: WinWord.exe
selection_dll:
CommandLine|contains|all:
- "/l "
- .dll
condition: all of selection_*
falsepositives:
- Unknown
level: medium
license: DRL-1.1