Notepad Password Files Discovery — Sigma Rule

Rule metadata and linked tags

Author: The DFIR Report. Source status: experimental; severity: low. Source dates: 2025-02-21 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 70653418593828626e573955ee5a5858058266916901c7abca418b58d243aa47

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: Notepad Password Files Discovery
id: 3b4e950b-a3ea-44d3-877e-432071990709
status: experimental
description: Detects the execution of Notepad to open a file that has the string "password" which may indicate unauthorized access to credentials or suspicious activity.
references:
    - https://thedfirreport.com/2025/02/24/confluence-exploit-leads-to-lockbit-ransomware/
    - https://intel.thedfirreport.com/eventReports/view/57  # Private Report
author: 'The DFIR Report'
tags:
    - attack.discovery
    - attack.t1083
date: 2025-02-21
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        ParentImage|endswith: '\explorer.exe'
        Image|endswith: '\notepad.exe'
        CommandLine|endswith:
        # Note: Commandline to contain a file with the string password and a specific extension
            - 'password*.txt'
            - 'password*.csv'
            - 'password*.doc'
            - 'password*.xls'
    condition: selection
falsepositives:
    - Legitimate use of opening files from remote hosts by administrators or users. However, storing passwords in text readable format could potentially be a violation of the organization's policy. Any match should be investigated further.
level: low

Original YAML and metadata in JSON

False positives

• Legitimate use of opening files from remote hosts by administrators or users. However, storing passwords in text readable format could potentially be a violation of the organization's policy. Any match should be investigated further.

Source references

• https://thedfirreport.com/2025/02/24/confluence-exploit-leads-to-lockbit-ransomware/
• https://intel.thedfirreport.com/eventReports/view/57