CVE-2024-23678 - Exploiting Unsafe Path Handling and Deserialization in Splunk Enterprise for Windows
Splunk Enterprise is a big name when it comes to searching, monitoring, and analyzing machine-generated data. However, sometimes even the most adopted software can have serious issues, especially when security is overlooked. In this post, we’ll break down CVE-2024-23678—a critical vulnerability found in several versions of Splunk Enterprise for Windows. We’ll walk through how the flaw works, what makes it dangerous, and demonstrate how an attacker could exploit it. Let's keep it simple, clear, and actionable.
Versions below 9..8 and 9.1.3
The core issue is that Splunk does not correctly sanitize path input data when loading files. Specifically, path data pointing to other disk partitions can lead to unsafe deserialization—that is, Splunk accidentally loads and runs data the attacker controls.
> Note: Linux and other non-Windows platforms are not affected!
How Does the Vulnerability Happen?
Splunk Enterprise (on Windows) expects to use safe, trusted paths when reading and writing its data. But, versions below 9..8 and 9.1.3 fail to confirm whether a referenced path is on the same disk partition or whether it sneaks off to somewhere else.
So, if a user (or attacker) feeds Splunk a path like D:\evil\payload.pkl, Splunk may blindly load and deserialize any data at that location, no matter how malicious.
Deserialization is dangerous because it can let code run that's hidden inside data. If it’s not checked carefully, attackers can put crafted files in places Splunk will look and give them a way in.
Some way to convince Splunk to load a path to the attacker-controlled file
Once achieved, Splunk's workflow (say, indexing or restoring data) may load the malicious pickle (Python’s serialization format), and boom—the attacker’s code is running as the Splunk service account.
Example: Crafting a Malicious Pickle File
Splunk often uses Python "pickle" files for saving/loading objects on Windows. Here’s an example of a Python pickle payload that opens the calculator app (safe for demo, but proof of remote code execution potential).
import pickle
import os
class EvilPickle(object):
def __reduce__(self):
return (os.system, ('calc.exe',))
with open('C:\\evil\\payload.pkl', 'wb') as f:
pickle.dump(EvilPickle(), f)
The attacker somehow convinces Splunk to load this file via path input.
If Splunk runs this pickle file unsafely, calc.exe will pop up—proof that any code can be executed!
Plant Payload: Drops their malicious pickle payload at D:\badguy\payload.pkl.
3. Supply Path: Through Splunk’s interface or configuration, feeds path such as D:\badguy\payload.pkl.
4. Trigger Deserialization: Splunk, in affected versions, loads and deserializes the file without making sure it’s safe.
5. Gain Code Execution: The attacker's code runs with the permissions assigned to the Splunk process.
Official References
- Splunk Security Advisory: https://advisory.splunk.com/advisories/SVD-2024-0609
- CVE Details: https://nvd.nist.gov/vuln/detail/CVE-2024-23678
How to Fix
Upgrade immediately:
Final Thoughts
CVE-2024-23678 shows just how dangerous unsafe deserialization and unchecked paths can be, especially on Windows environments. If you’re running Splunk Enterprise for Windows and haven’t patched yet, stop reading and upgrade now.
If you're a Blue Team defender, check your logs for any unusual loading of files from unexpected partitions, and audit which users are allowed to configure file paths.
Stay safe, patch quickly, and always check your deserialization hygiene—because attackers only need one vulnerable input to make a whole enterprise topple.
> *This article is crafted for clarity and practical security insight. For official info and the latest updates, always refer to Splunk’s security advisories. Feel free to share or quote with proper credits.*
Timeline
Published on: 01/22/2024 21:15:10 UTC
Last modified on: 01/29/2024 17:44:47 UTC