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splunk-security_content/detections/endpoint/linux_java_spawning_shell.yml
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author: Michael Haag, Splunk
datamodel:
- Endpoint.Processes
date: '2021-12-13'
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.
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.
id: 7b09db8a-5c20-11ec-9945-acde48001122
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.
name: Linux Java Spawning Shell
references:
- https://blog.netlab.360.com/ten-families-of-malicious-samples-are-spreading-using-the-log4j2-vulnerability-now/
- https://gist.github.com/olafhartong/916ebc673ba066537740164f7e7e1d72
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=java
OR Processes.parent_process_name=apache OR Processes.parent_process_name=tomcat
`linux_shells` by Processes.dest Processes.user Processes.parent_process_name Processes.process_name
Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_java_spawning_shell_filter`'
tags:
analytic_story:
- Log4Shell CVE-2021-44228
confidence: 50
context:
- Source:Endpoint
- Stage:Defense Evasion
cve:
- CVE-2021-44228
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/java/java_spawn_shell_nix.log
impact: 80
kill_chain_phases:
- Exploitation
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
role:
- Victim
type: Hostname
- name: parent_process_name
role:
- Parent Process
type: Parent Process
- name: process_name
role:
- Child Process
type: Process
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- Endpoint.Processes.dest
- Endpoint.Processes.parent_process_id
- Endpoint.Processes.parent_process_name
- Endpoint.Processes.process
- Endpoint.Processes.process_id
- Endpoint.Processes.process_name
- Endpoint.Processes.user
- _time
risk_score: 40
security_domain: endpoint
type: TTP
version: 1