name: Linux c89 Privilege Escalation
id: 54c95f4d-3e5d-44be-9521-ea19ba62f7a8
version: 1
date: '2022-08-11'
author: Gowthamaraj Rajendran, Splunk
status: production
type: Anomaly
description: The c89 and cc commands compile, assemble, and link-edit C programs;
  the cxx or c++ command does the same for C++ programs. The c89 command should be
  used when compiling C programs that are written according to Standard C. If sudo
  right is given to c89 application 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: '*-wrapper*'
  selection2:
    CommandLine: '*c89*'
  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/c89/
- https://www.ibm.com/docs/en/zos/2.1.0?topic=guide-c89-compiler-invocation-using-host-environment-variables
tags:
  analytic_story:
  - Linux Privilege Escalation
  - Linux Living Off The Land
  asset_type: Endpoint
  confidence: 50
  impact: 60
  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: 30
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548/c89/sysmon_linux.log
    source: Syslog:Linux-Sysmon/Operational
    sourcetype: sysmon:linux
    update_timestamp: true