Detection: Splunk Code Injection via custom dashboard leading to RCE

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-05-24 ID: b06b41d7-9570-4985-8137-0784f582a1b3 Author: Rod Soto Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic identifies attempts to exploit a vulnerability in Splunk Enterprise versions below 8.2.9, 8.1.12, and 9.0.2, where an authenticated user can execute arbitrary code via the dashboard PDF generation component. It detects this activity by analyzing events in the _internal index with the file=export parameter. This behavior is significant because it indicates a potential code injection attack, which could lead to remote code execution (RCE). If confirmed malicious, an attacker could gain unauthorized access, execute arbitrary commands, and potentially compromise the entire Splunk environment.

 1`splunkd_ui` uri_path=*/data/ui/views/* OR uri_path=*saved/searches/* 
 2| dedup uri_path 
 3| eval URL=urldecode("uri_path")
 4| rex field=URL "\/saved\/searches\/(?<NAME>[^\/]*)" 
 5| rex field=URL "\/data\/ui\/views\/(?<NAME1>[^\/]*)" 
 6| eval NAME=NAME."( Saved Search )",NAME1=NAME1."( Dashboard )" 
 7| eval NAME=coalesce(NAME,NAME1) 
 8| eval STATUS=case(match(status,"2\d+"),"SUCCESS",match(status,"3\d+"),"REDIRECTION",match(status,"4\d+") OR match(status,"5\d+"),"ERROR") 
 9| stats list(NAME) as DASHBOARD_TITLE,list(method) as HTTP_METHOD,list(status) as Status_Code,list(STATUS) as STATUS by user 
10| rename user as User 
11| `splunk_code_injection_via_custom_dashboard_leading_to_rce_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name Value
splunkd_ui index=_internal sourcetype=splunkd_ui_access
splunk_code_injection_via_custom_dashboard_leading_to_rce_filter search *
splunk_code_injection_via_custom_dashboard_leading_to_rce_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1210 Exploitation of Remote Services Lateral Movement
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.CIS_10
APT28
Dragonfly
Earth Lusca
Ember Bear
FIN7
Fox Kitten
MuddyWater
Threat Group-3390
Tonto Team
Wizard Spider
menuPass

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 Risk Event False
This configuration file applies to all detections of type hunting.

Implementation

This detection does not require you to ingest any new data. The detection does require the ability to search the _internal index.

Known False Positives

Not all exports and downloads are malicious, special attention must be put as well on /en-US/splunkd/__raw/services/pdfgen/render in the context of this search.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Potential exploitation of Code Injection via Dashboard PDF generation. 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit ✅ Passing Dataset /opt/splunk/var/log/splunk/splunkd_ui_access.log splunkd_ui_access
Integration ✅ Passing Dataset /opt/splunk/var/log/splunk/splunkd_ui_access.log splunkd_ui_access

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: 2