splunk-security_content/docs/_posts/2021-12-13-windows_java_spawning_shells.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Windows Java Spawning Shells	Exploit Public-Facing Application	Endpoint	2021-12-13	true		Exploit Public-Facing Application Initial Access Splunk Enterprise Splunk Enterprise Security Splunk Cloud CVE-2021-44228 Endpoint

⚠️ WARNING THIS IS A EXPERIMENTAL DETECTION

We have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.

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Description

The following analytic identifies the process name of java.exe and w3wp.exe spawning a Windows 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 "cmd.exe", "powershell.exe". Upon triage, review parallel processes and command-line arguments to determine legitimacy.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-12-13
• Author: Michael Haag, Splunk
• ID: 28c81306-5c47-11ec-bfea-acde48001122

ATT&CK

ID	Technique	Tactic
T1190	Exploit Public-Facing Application	Initial Access

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=java.exe OR Processes.parent_process_name=w3wp.exe `windows_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)` 
| `windows_java_spawning_shells_filter`

Associated Analytic Story

• Log4Shell CVE-2021-44228

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. Restrict the analytic to publicly facing endpoints to reduce false positives. Add any additional identified web application process name to the query. Add any further Windows process names to the macro (ex. LOLBins) to further expand this query.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process_name
• Processes.parent_process
• Processes.original_file_name
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_path
• Processes.process_path
• Processes.parent_process_id

Kill Chain Phase

• Exploitation

Known False Positives

Filtering may be required on internal developer build systems or classify assets as web facing and restrict the analytic based on that.

RBA

Risk Score	Impact	Confidence	Message
40.0	80	50	An instance of parent_process_name spawning process_name was identified on endpoint dest spawning a Windows shell, potentially indicative of exploitation.

CVE

ID	Summary	CVSS
CVE-2021-44228	Apache Log4j2 2.0-beta9 through 2.12.1 and 2.13.0 through 2.15.0 JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0, this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.	9.3

Reference

• https://blog.netlab.360.com/ten-families-of-malicious-samples-are-spreading-using-the-log4j2-vulnerability-now/
• https://gist.github.com/olafhartong/916ebc673ba066537740164f7e7e1d72

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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