Potential Persistence Via Outlook Home Page — Sigma Rule

Rule metadata and linked tags

Author: Tobias Michalski (Nextron Systems), David Bertho (@dbertho) & Eirik Sveen (@0xSV1), Storebrand. Source status: test; severity: high. Source dates: 2021-06-09 / 2024-08-07.

{
  "product": "windows",
  "category": "registry_set"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: d935f49fba67eee087ac12bb9b77d0e790d2227bf3ace5c181a8384bd1a6813f

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Potential Persistence Via Outlook Home Page
id: ddd171b5-2cc6-4975-9e78-f0eccd08cc76
related:
    - id: 487bb375-12ef-41f6-baae-c6a1572b4dd1
      type: similar
status: test
description: |
    Detects potential persistence activity via outlook home page.
    An attacker can set a home page to achieve code execution and persistence by editing the WebView registry keys.
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-persistence-via-microsoft-exchange-server-or-outlook?slide=70
    - https://support.microsoft.com/en-us/topic/outlook-home-page-feature-is-missing-in-folder-properties-d207edb7-aa02-46c5-b608-5d9dbed9bd04?ui=en-us&rs=en-us&ad=us
    - https://trustedsec.com/blog/specula-turning-outlook-into-a-c2-with-one-registry-change
author: Tobias Michalski (Nextron Systems), David Bertho (@dbertho) & Eirik Sveen (@0xSV1), Storebrand
date: 2021-06-09
modified: 2024-08-07
tags:
    - attack.persistence
    - attack.defense-impairment
    - attack.t1112
logsource:
    product: windows
    category: registry_set
detection:
    selection:
        TargetObject|contains|all:
            - '\Software\Microsoft\Office\'
            - '\Outlook\WebView\'
        TargetObject|endswith: '\URL'
    condition: selection
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://speakerdeck.com/heirhabarov/hunting-for-persistence-via-microsoft-exchange-server-or-outlook?slide=70
• https://support.microsoft.com/en-us/topic/outlook-home-page-feature-is-missing-in-folder-properties-d207edb7-aa02-46c5-b608-5d9dbed9bd04?ui=en-us&rs=en-us&ad=us
• https://trustedsec.com/blog/specula-turning-outlook-into-a-c2-with-one-registry-change