Potential Suspicious Browser Launch From Document Reader Process — Sigma Rule

Rule metadata and linked tags

Author: Joseph Kamau. Source status: test; severity: medium. Source dates: 2024-05-27 / 2025-10-07.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: fa78456ddc8ac8dd0d285fcf3d674ff393c2239d99fb4e5930c5ec738f9a2bc7

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 Suspicious Browser Launch From Document Reader Process
id: 1193d960-2369-499f-a158-7b50a31df682
status: test
description: |
    Detects when a browser process or browser tab is launched from an application that handles document files such as Adobe, Microsoft Office, etc. And connects to a web application over http(s), this could indicate a possible phishing attempt.
references:
    - https://app.any.run/tasks/69c5abaa-92ad-45ba-8c53-c11e23e05d04/ # PDF Document
    - https://app.any.run/tasks/64043a79-165f-4052-bcba-e6e49f847ec1/ # Office Document
author: Joseph Kamau
date: 2024-05-27
modified: 2025-10-07
tags:
    - attack.execution
    - attack.t1204.002
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        ParentImage|contains:
            - 'Acrobat Reader'
            - 'Microsoft Office'
            - 'PDF Reader'
        Image|endswith:
            - '\brave.exe'
            - '\chrome.exe'
            - '\firefox.exe'
            - '\msedge.exe'
            - '\opera.exe'
            - '\maxthon.exe'
            - '\seamonkey.exe'
            - '\vivaldi.exe'
        CommandLine|contains: 'http'
    filter_main_microsoft_help:
        CommandLine|contains: 'https://go.microsoft.com/fwlink/'
    filter_optional_foxit:
        CommandLine|contains:
            - 'http://ad.foxitsoftware.com/adlog.php?'
            - 'https://globe-map.foxitservice.com/go.php?do=redirect'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unlikely in most cases, further investigation should be done in the commandline of the browser process to determine the context of the URL accessed.
level: medium

Original YAML and metadata in JSON

False positives

• Unlikely in most cases, further investigation should be done in the commandline of the browser process to determine the context of the URL accessed.

Source references

• https://app.any.run/tasks/69c5abaa-92ad-45ba-8c53-c11e23e05d04/
• https://app.any.run/tasks/64043a79-165f-4052-bcba-e6e49f847ec1/