Detection: Splunk Image File Disclosure via PDF Export in Classic Dashboard

Updated Date: 2024-10-17 ID: 7464e2dc-98a5-4af9-87a1-fa6d5a256fa6 Author: Rod Soto Type: Hunting Product: Splunk Enterprise Security

Description

In Splunk Enterprise versions 9.3.0, 9.2.3, and 9.1.6, a low-privileged user that does not hold the “admin” or “power” Splunk roles could view images on the host machine using the PDF export feature in Splunk classic dashboards.

Search

 1```Search for any PDFs that have been generated```
 2index=_internal sourcetype=splunk_pdfgen "Generated pdf" 
 3```Extract a potential Dashboard Filename```
 4
 5| rex field=filename "(?<title>.*)-[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}.pdf" 
 6```Join this with all dashboards. Potentially vulnerable dashbaords MUST be classic (version 1.1) AND contain at least one <img...> tag```
 7
 8| join type=inner title 
 9    [
10| rest /servicesNS/-/-/data/ui/views 
11    
12| search eai:data="*<img*" version="1.1"] 
13
14| stats count min(_time) as earliestTime max(_time) as latestTime by author eai:acl.app label title eai:data
15
16| `security_content_ctime(earliestTime)`
17
18| `security_content_ctime(latestTime)`
19
20| `splunk_image_file_disclosure_via_pdf_export_in_classic_dashboard_filter`

Data Source

Name	Platform	Sourcetype	Source
Splunk	Splunk	`'splunkd_ui_access'`	`'splunkd_ui_access.log'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
splunk_image_file_disclosure_via_pdf_export_in_classic_dashboard_filter	`search *`

splunk_image_file_disclosure_via_pdf_export_in_classic_dashboard_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
T1087	Account Discovery	Discovery

KillChainPhase.EXPLOITAITON

NistCategory.DE_AE

Cis18Value.CIS_10

Aquatic Panda

FIN13

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

Need to access to REST API.

Known False Positives

This is a hunting search and operator must identify indicators of local host image source such as UNC paths ('C:'', '//'') in order to identify potential exploitation of this vulnerability.

Associated Analytic Story

Splunk Vulnerabilities

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Potential disclosure of local system source images in dashbaord $label$ by $author$	8	10	80

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

https://advisory.splunk.com/advisories/SVD-2024-1004

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	N/A	`N/A`	`N/A`
Integration	✅ Passing	N/A	`N/A`	`N/A`

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