name: Linux GNU Awk Privilege Escalation
id: 0dcf43b9-50d8-42a6-acd9-d1c9201fe6ae
version: 1
date: '2022-08-09'
author: Gowthamaraj Rajendran, Splunk
type: Anomaly
datamodel:
- Endpoint
description: gawk command in Linux is used for pattern scanning and processing language. The awk command requires no compiling and allows the user to use variables, numeric functions, string functions, and logical operators. It is a utility that enables programmers to write tiny and effective programs in the form of statements 
  that define text patterns that are to be searched for, in a text document and the action that is to be taken when a match is found within a line.
  If sudo right is given to gawk tool for the user, then the user can run system commands as root and possibly get a root shell.
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where Processes.process="*gawk*" AND Processes.process="*BEGIN*{system*" AND Processes.process="*sudo*" by Processes.dest Processes.user Processes.parent_process_name
  Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
  Processes.process_guid | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `linux_gnu_awk_privilege_escalation_filter`'
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/gawk/
- https://www.geeksforgeeks.org/gawk-command-in-linux-with-examples/
tags:
  analytic_story:
  - Linux Privilege Escalation
  - Linux Living Off The Land
  asset_type: Endpoint
  cis20:
  - CIS 3
  - CIS 5
  - CIS 16
  confidence: 50
  context:
  - Source:Endpoint
  - Stage:Privilege Escalation
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548/gawk/sysmon_linux.log
  impact: 60
  kill_chain_phases:
  - Exploitation
  message: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$
  mitre_attack_id:
  - T1548.003
  - T1548
  nist:
  - DE.CM
  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
  required_fields:
  - _time
  - Processes.dest
  - Processes.user
  - Processes.parent_process_name
  - Processes.process_name
  - Processes.process
  - Processes.process_id
  - Processes.parent_process_id
  risk_score: 30
  security_domain: endpoint