Findstr Launching .lnk File — Sigma Rule

Rule metadata and linked tags

Author: Trent Liffick. Source status: test; severity: medium. Source dates: 2020-05-01 / 2024-01-15.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 5dd388c20396247c9b604dea1ab6a9a31b272d6415964d2a63ddd369d96754f9

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: Findstr Launching .lnk File
id: 33339be3-148b-4e16-af56-ad16ec6c7e7b
status: test
description: Detects usage of findstr to identify and execute a lnk file as seen within the HHS redirect attack
references:
    - https://www.bleepingcomputer.com/news/security/hhsgov-open-redirect-used-by-coronavirus-phishing-to-spread-malware/
author: Trent Liffick
date: 2020-05-01
modified: 2024-01-15
tags:
    - attack.stealth
    - attack.t1036
    - attack.t1202
    - attack.t1027.003
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\find.exe'
              - '\findstr.exe'
        - OriginalFileName:
              - 'FIND.EXE'
              - 'FINDSTR.EXE'
    selection_cli:
        CommandLine|endswith:
            - '.lnk'
            - '.lnk"'
            - ".lnk'"
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.bleepingcomputer.com/news/security/hhsgov-open-redirect-used-by-coronavirus-phishing-to-spread-malware/