clear_unallocated_sector_using_cipher_app.yml

name: Clear Unallocated Sector Using Cipher App
id: cd80a6ac-c9d9-11eb-8839-acde48001122
version: 1
date: '2021-06-10'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: this search is to detect execution of `cipher.exe` to clear the unallocated
  sectors of a specific disk. This technique was seen in some ransomware to make it
  impossible to forensically recover deleted files.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    CommandLine: '*/w:*'
    Image|endswith: cipher.exe
  condition: selection1
how_to_implement: To successfully implement this search you need to be ingesting information
  on process that include the name of the process responsible for the changes from
  your endpoints into the `Endpoint` datamodel in the `Processes` node.
known_false_positives: administrator may execute this app to manage disk
references:
- https://unit42.paloaltonetworks.com/vatet-pyxie-defray777/3/
- https://www.sophos.com/en-us/medialibrary/PDFs/technical-papers/sophoslabs-ransomware-behavior-report.pdf
tags:
  analytic_story:
  - Ransomware
  asset_type: Endpoint
  confidence: 90
  impact: 100
  message: An instance of $parent_process_name$ spawning $process_name$ was identified
    on endpoint $dest$ by user $user$ attempting to clear the unallocated sectors
    of a specific disk.
  mitre_attack_id:
  - T1070.004
  - T1070
  observable:
  - name: user
    type: User
    role:
    - Victim
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: parent_process_name
    type: Process
    role:
    - Parent Process
  - name: process_name
    type: Process
    role:
    - Child Process
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 90
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/ransomware_ttp/data1/windows-sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog