Writing Of Malicious Files To The Fonts Folder — Sigma Rule

Rule metadata and linked tags

Author: Sreeman. Source status: test; severity: medium. Source dates: 2020-04-21 / 2022-03-08.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 76faa8c1538244a2e6cd2f0be1b1c130fcb082b41a5c90a34b59ddddd9933d53

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: Writing Of Malicious Files To The Fonts Folder
id: ae9b0bd7-8888-4606-b444-0ed7410cb728
status: test
description: Monitors for the hiding possible malicious files in the C:\Windows\Fonts\ location. This folder doesn't require admin privillege to be written and executed from.
references:
    - https://thedfirreport.com/2020/04/20/sqlserver-or-the-miner-in-the-basement/
author: Sreeman
date: 2020-04-21
modified: 2022-03-08
tags:
    - attack.stealth
    - attack.t1211
    - attack.t1059
    - attack.persistence
    - attack.execution
logsource:
    product: windows
    category: process_creation
detection:
    selection_1:
        CommandLine|contains:
            - 'echo'
            - 'copy'
            - 'type'
            - 'file createnew'
            - 'cacls'
    selection_2:
        CommandLine|contains: 'C:\Windows\Fonts\'
    selection_3:
        CommandLine|contains:
            - '.sh'
            - '.exe'
            - '.dll'
            - '.bin'
            - '.bat'
            - '.cmd'
            - '.js'
            - '.msh'
            - '.reg'
            - '.scr'
            - '.ps'
            - '.vb'
            - '.jar'
            - '.pl'
            - '.inf'
            - '.cpl'
            - '.hta'
            - '.msi'
            - '.vbs'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://thedfirreport.com/2020/04/20/sqlserver-or-the-miner-in-the-basement/