Windows: Outlook loads outlvba.dll (VBA for Outlook add-in) via image loading

Alerts on outlvba.dll being loaded by outlook.exe, indicating VBA add-in execution within Outlook.

FreeReviewedSigma · Medium · v2

Product: windows
Category: image_load
Author: Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2023-02-08
Updated: 2026-07-31

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1204.002Malicious File
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies the Windows Outlook process (outlook.exe) loading outlvba.dll, which is associated with Microsoft VBA for Outlook add-ins. Attackers can abuse VBA-enabled features to execute or persist malicious logic within the context of the Outlook application. The detection relies on image load telemetry that records which DLLs are loaded by a process and matches the specific module name loaded by outlook.exe.

Reporting behind it

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Windows: Outlook loads outlvba.dll (VBA for Outlook add-in) via image loading

Pivot detection · T1204.002 · 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.

outlook-process-loads-outlvba-dll-microsoft-vba-add-in-on-windows-9a0b8719

title: "Windows: Outlook loads outlvba.dll (VBA for Outlook add-in) via image loading"
id: 5cac07bb-d4ed-4112-a653-2b49d627aa23
status: test
description: This rule identifies the Windows Outlook process (outlook.exe) loading outlvba.dll, which is associated with Microsoft VBA for Outlook add-ins. Attackers can abuse VBA-enabled features to execute or persist malicious logic within the context of the Outlook application. The detection relies on image load telemetry that records which DLLs are loaded by a process and matches the specific module name loaded by outlook.exe.
references:
  - https://speakerdeck.com/heirhabarov/hunting-for-persistence-via-microsoft-exchange-server-or-outlook?slide=58
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/image_load/image_load_office_outlook_outlvba_load.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2023-02-08
modified: 2024-03-12
tags:
  - attack.execution
  - attack.t1204.002
logsource:
  category: image_load
  product: windows
detection:
  selection:
    Image|endswith: \outlook.exe
    ImageLoaded|endswith: \outlvba.dll
  condition: selection
falsepositives:
  - Legitimate macro usage. Add the appropriate filter according to your environment
level: medium
license: DRL-1.1
related:
  - id: 9a0b8719-cd3c-4f0a-90de-765a4cb3f5ed
    type: derived

Convert

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