Windows Registry: Office VBAWarning Disabled (VBAWarnings set to 1)

Alerts on Security\VBAWarnings being set to DWORD 0x00000001, enabling all Office VBA macros.

FreeUnreviewedSigmahighv1

windows-registry-office-vbawarning-disabled-vbawarnings-set-to-1-91239011

title: "Windows Registry: Office VBAWarning Disabled (VBAWarnings set to 1)"
id: ef02c2ce-87e2-4395-8d52-3f2e08ab7dae
related:
  - id: 9b894e57-033f-46cf-b7fa-a52804181973
    type: obsolete
  - id: 91239011-fe3c-4b54-9f24-15c86bb65913
    type: derived
status: test
description: This rule flags Windows registry changes under the Security\VBAWarnings path where the VBAWarnings setting is set to DWORD value 0x00000001. That configuration enables execution of all Microsoft Office VBA macros, regardless of whether they are signed. Attackers can use defense-impairing changes like this to reduce macro security controls. Telemetry relied upon is registry set events capturing the modified target path and the DWORD value written.
references:
  - https://twitter.com/inversecos/status/1494174785621819397
  - https://www.mcafee.com/blogs/other-blogs/mcafee-labs/zloader-with-a-new-infection-technique/
  - https://securelist.com/scarcruft-surveilling-north-korean-defectors-and-human-rights-activists/105074/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_office_vba_warnings_tamper.yml
author: Trent Liffick (@tliffick), Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2020-05-22
modified: 2024-03-19
tags:
  - attack.persistence
  - attack.defense-impairment
  - attack.t1112
logsource:
  category: registry_set
  product: windows
detection:
  selection:
    TargetObject|endswith: \Security\VBAWarnings
    Details: DWORD (0x00000001)
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1

What it detects

This rule flags Windows registry changes under the Security\VBAWarnings path where the VBAWarnings setting is set to DWORD value 0x00000001. That configuration enables execution of all Microsoft Office VBA macros, regardless of whether they are signed. Attackers can use defense-impairing changes like this to reduce macro security controls. Telemetry relied upon is registry set events capturing the modified target path and the DWORD value written.

Known false positives

Unlikely

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.