name: Linux Shred Overwrite Command
id: c1952cf1-643c-4965-82de-11c067cbae76
version: 1
date: '2022-04-22'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: This analytic is to detect a shred process to overwrite a files in a
  linux machine. Shred Linux application is designed to overwrite file to hide its
  contents or make the deleted file un-recoverable. Weve seen this technique in industroyer2
  malware that tries to wipe energy facilities of targeted sector as part of its destructive
  attack. It might be some normal user may use this command for valid purposes but
  it is recommended to check what files, disk or folder it tries to shred that might
  be good pivot for incident response in this type of destructive malware.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    CommandLine:
    - '*-n*'
    - '*-u*'
    - '*-z*'
    - '*-s*'
    Image|endswith: shred
  condition: selection1
how_to_implement: To successfully implement this search, you need to be ingesting
  logs with the process name, parent process, and command-line executions from your
  endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from
  Splunkbase.
known_false_positives: Administrator or network operator can use this application
  for automation purposes. Please update the filter macros to remove false positives.
references:
- https://www.welivesecurity.com/2022/04/12/industroyer2-industroyer-reloaded/
- https://cert.gov.ua/article/39518
tags:
  analytic_story:
  - Industroyer2
  - Linux Privilege Escalation
  - Linux Persistence Techniques
  asset_type: Endpoint
  confidence: 70
  impact: 70
  message: A possible shred overwrite command $process$ executed on $dest$
  mitre_attack_id:
  - T1485
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 49
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1485/rm_shred_critical_dir/sysmon_linux.log
    source: Syslog:Linux-Sysmon/Operational
    sourcetype: sysmon:linux