name: Linux Cpulimit Privilege Escalation
id: d4e40b7e-aad3-4a7d-aac8-550ea5222be5
version: 1
date: '2022-08-11'
author: Gowthamaraj Rajendran, Splunk
status: production
type: Anomaly
description: cpulimit is a simple program which attempts to limit the cpu usage of
  a process (expressed in percentage, not in cpu time). This is useful to control
  batch jobs, when you don't want them to eat too much cpu. If sudo right is given
  to the program for the user, then the user can run system commands as root and possibly
  get a root shell.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    CommandLine: '*-l*'
  selection2:
    CommandLine: '*cpulimit*'
  selection3:
    CommandLine: '*-f*'
  selection4:
    CommandLine: '*sudo*'
  condition: selection1 and selection2 and selection3 and selection4
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 into the Endpoint datamodel. If you are using Sysmon, you can use the
  Add-on for Linux Sysmon from Splunkbase.
known_false_positives: False positives may be present, filter as needed.
references:
- https://gtfobins.github.io/gtfobins/cpulimit/
- http://cpulimit.sourceforge.net/
tags:
  analytic_story:
  - Linux Privilege Escalation
  - Linux Living Off The Land
  asset_type: Endpoint
  confidence: 50
  impact: 40
  message: An instance of $parent_process_name$ spawning $process_name$ was identified
    on endpoint $dest$
  mitre_attack_id:
  - T1548.003
  - T1548
  observable:
  - 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: 20
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548/cpulimit/sysmon_linux.log
    source: Syslog:Linux-Sysmon/Operational
    sourcetype: sysmon_linux
    update_timestamp: true