Potential Suspicious Browser Launch From Document Reader Process

SIGMA detection rule by Joseph Kamau · NOASSERTION

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.

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

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

63ce47b2-a6ae-4fcf-960c-97e71a88bc72

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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