Detection: Shai-Hulud 2 Exfiltration Artifact Files

Description

Detects creation of exfiltration artifact files associated with Shai-Hulud 2.0 npm supply chain malware. The malware creates cloud.json, contents.json, environment.json, truffleSecrets.json, and actionsSecrets.json files containing harvested credentials from AWS, Azure, GCP, GitHub secrets, and environment variables. These files are staged before being pushed to attacker-controlled repositories.

 1
 2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime
 3
 4from datamodel=Endpoint.Filesystem where
 5
 6Filesystem.file_name IN (
 7  "cloud.json",
 8  "contents.json",
 9  "environment.json",
10  "truffleSecrets.json",
11  "actionsSecrets.json"
12)
13
14by Filesystem.action Filesystem.dest Filesystem.file_access_time Filesystem.file_create_time
15   Filesystem.file_hash Filesystem.file_modify_time Filesystem.file_name Filesystem.file_path Filesystem.file_acl Filesystem.file_size Filesystem.process_guid Filesystem.process_id Filesystem.user
16   Filesystem.vendor_product
17
18
19| `drop_dm_object_name(Filesystem)`
20
21| `security_content_ctime(firstTime)`
22
23| `security_content_ctime(lastTime)`
24
25| `shai_hulud_2_exfiltration_artifact_files_filter`

Data Source

Name Platform Sourcetype Source
Sysmon for Linux EventID 11 Linux icon Linux 'sysmon:linux' 'Syslog:Linux-Sysmon/Operational'
Sysmon EventID 11 Windows icon Windows 'XmlWinEventLog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Name Value
security_content_summariesonly summariesonly=summariesonly_config allow_old_summaries=oldsummaries_config fillnull_value=fillnull_config``
shai_hulud_2_exfiltration_artifact_files_filter search *
shai_hulud_2_exfiltration_artifact_files_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

Default Configuration

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

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Finding (Notable) Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Intermediate Finding (Risk Event) No
TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

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 filesystem events, specifically file creation events. 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 Filesystem 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

Low but possible. Generic filenames like cloud.json or environment.json may appear in legitimate contexts. Correlate with npm install activity or suspicious parent processes.

Associated Analytic Story

Finding

Title Entity Field Entity Type Risk Score
Shai-Hulud 2.0 exfiltration artifact $file_name$ created on $dest$ dest system 50

Threat Objects

Field Type
file_name file_name

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Passing N/A N/A N/A
Unit Passing Dataset Syslog:Linux-Sysmon/Operational sysmon:linux
Integration ✅ Passing Dataset Syslog:Linux-Sysmon/Operational sysmon:linux

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: 4