Detection: Outbound Network Connection from Java Using Default Ports

Description

The following analytic detects outbound network connections from Java processes to default ports used by LDAP and RMI protocols, which may indicate exploitation of the CVE-2021-44228-Log4j vulnerability. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and network traffic logs. Monitoring this activity is crucial as it can signify an attacker’s attempt to perform JNDI lookups and retrieve malicious payloads. If confirmed malicious, this activity could lead to remote code execution and further compromise of the affected server.

Search

 1
 2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where (Processes.process_name="java.exe" OR Processes.process_name=javaw.exe OR Processes.process_name=javaw.exe) by _time Processes.process_id Processes.process_name Processes.dest Processes.process_path Processes.process Processes.parent_process_name 
 3| `drop_dm_object_name(Processes)` 
 4| `security_content_ctime(firstTime)` 
 5| `security_content_ctime(lastTime)` 
 6| join process_id [
 7| tstats `security_content_summariesonly` count FROM datamodel=Network_Traffic.All_Traffic where (All_Traffic.dest_port= 389 OR All_Traffic.dest_port= 636 OR All_Traffic.dest_port = 1389 OR All_Traffic.dest_port = 1099 ) by All_Traffic.process_id All_Traffic.dest All_Traffic.dest_port 
 8| `drop_dm_object_name(All_Traffic)` 
 9| rename dest as connection_to_CNC] 
10| table _time dest parent_process_name process_name process_path process connection_to_CNC dest_port
11| `outbound_network_connection_from_java_using_default_ports_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Sysmon EventID 1	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'	N/A

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

Legitimate Java applications may use perform outbound connections to these ports. Filter as needed

Associated Analytic Story

• Log4Shell CVE-2021-44228

Risk Based Analytics (RBA)

References

• https://www.lunasec.io/docs/blog/log4j-zero-day/

• https://www.govcert.admin.ch/blog/zero-day-exploit-targeting-popular-java-library-log4j/

Detection Testing

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

Source: GitHub | Version: 3