:warning: THIS IS A EXPERIMENTAL DETECTION

This detection has been marked experimental by the Splunk Threat Research team. This means 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 creation of lookup files in Splunk, which could indicate an attempt to exploit remote code execution via user-supplied XSLT. It leverages REST API queries to monitor the creation of these lookups, focusing on fields such as title, author, and access control lists. This activity is significant because it targets a known vulnerability in Splunk versions 9.1.x, potentially allowing attackers to execute arbitrary code. If confirmed malicious, this could lead to unauthorized code execution, compromising the integrity and security of the Splunk environment.

  • Type: Hunting

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-16
  • Author: Rod Soto, Splunk
  • ID: a053e6a6-2146-483a-9798-2d43652f3299

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1210 Exploitation of Remote Services Lateral Movement
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE
ID Summary CVSS
    


1
2
3
4



| rest splunk_server=local /services/data/lookup-table-files/ 
| fields title author disabled eai:acl.app eai:acl.owner eai:acl.sharing eai:appName eai:data 
| `splunk_app_for_lookup_file_editing_rce_via_user_xslt_filter`

Macros

The SPL above uses the following Macros:

:information_source: splunk_app_for_lookup_file_editing_rce_via_user_xslt_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • title
  • author
  • disabled
  • ea:acl.app
  • eai:acl.owner
  • eai:acl.sharing
  • eai:appName
  • eai:data

How To Implement

Because there is no way to detect the payload, this search only provides the ability to monitor the creation of lookups which are the base of this exploit. An operator must then investigate suspicious lookups. This search requires ability to perform REST queries. Note that if the Splunk App for Lookup File Editing is not, or was not, installed in the Splunk environment then it is not necessary to run the search as the enviornment was not vulnerable.

Known False Positives

This search will provide information for investigation and hunting of lookup creation via user-supplied XSLT which may be indications of possible exploitation. There will be false positives as it is not possible to detect the payload executed via this exploit.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
1.0 50 2 Please review $eai:acl.app$ for possible malicious lookups

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

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

source | version: 2