name: Linux Java Spawning Shell
id: 7b09db8a-5c20-11ec-9945-acde48001122
version: 1
date: '2021-12-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies the process name of Java, Apache, or
  Tomcat spawning a Linux shell. This is potentially indicative of exploitation of
  the Java application and may be related to current event CVE-2021-44228 (Log4Shell).
  The shells included in the macro are "sh", "ksh", "zsh", "bash", "dash", "rbash",
  "fish", "csh', "tcsh', "ion", "eshell". Upon triage, review parallel processes and
  command-line arguments to determine legitimacy.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    ParentImage:
    - java
    - apache
    - tomcat
  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 for Linux, you will need to ensure mapping is
  occurring correctly. Ensure EDR product is mapping OS Linux to the datamodel properly.
  Add any additional java process names for your environment to the analytic as needed.
known_false_positives: Filtering may be required on internal developer build systems
  or classify assets as web facing and restrict the analytic based on asset type.
references:
- https://blog.netlab.360.com/ten-families-of-malicious-samples-are-spreading-using-the-log4j2-vulnerability-now/
- https://gist.github.com/olafhartong/916ebc673ba066537740164f7e7e1d72
tags:
  analytic_story:
  - Hermetic Wiper
  - Log4Shell CVE-2021-44228
  - Spring4Shell CVE-2022-22965
  asset_type: Endpoint
  confidence: 50
  cve:
  - CVE-2021-44228
  impact: 80
  message: An instance of $parent_process_name$ spawning $process_name$ was identified
    on endpoint $dest$ spawning a Linux shell, potentially indicative of exploitation.
  mitre_attack_id:
  - T1190
  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: 40
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/java/java_spawn_shell_nix.log
    source: Syslog:Linux-Sysmon/Operational
    sourcetype: sysmon_linux