name: Linux Gem Privilege Escalation
id: 0115482a-5dcb-4bb0-bcca-5d095d224236
version: 1
date: '2022-08-09'
author: Gowthamaraj Rajendran, Splunk
status: production
type: Anomaly
description: RubyGems is a package manager for the Ruby programming language that
  provides a standard format for distributing Ruby programs and libraries (in a self-contained
  format called a "gem"), a tool designed to easily manage the installation of gems,
  and a server for distributing them. If sudo right is given to GEM utility 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: '*-c*'
  selection2:
    CommandLine: '*gem*open*-e*'
  selection3:
    CommandLine: '*sudo*'
  condition: selection1 and selection2 and selection3
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/gem/
- https://en.wikipedia.org/wiki/RubyGems
tags:
  analytic_story:
  - Linux Privilege Escalation
  - Linux Living Off The Land
  asset_type: Endpoint
  confidence: 50
  impact: 20
  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: 10
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548/gem/sysmon_linux.log
    source: Syslog:Linux-Sysmon/Operational
    sourcetype: sysmon_linux
    update_timestamp: true