CVE-2025-20229
📋 TL;DR
This vulnerability allows low-privileged Splunk users without admin or power roles to execute arbitrary code on the server by uploading files to a specific directory. It affects Splunk Enterprise versions below 9.3.3, 9.2.5, and 9.1.8, and Splunk Cloud Platform versions below specific builds. The issue stems from missing authorization checks for file uploads to the apptemp directory.
💻 Affected Systems
- Splunk Enterprise
- Splunk Cloud Platform
📦 What is this software?
Splunk by Splunk
Splunk by Splunk
Splunk by Splunk
Splunk by Splunk
⚠️ Risk & Real-World Impact
Worst Case
An attacker with any authenticated user account could gain full control of the Splunk server, potentially leading to data exfiltration, lateral movement, or complete system compromise.
Likely Case
Malicious insiders or compromised low-privileged accounts could execute arbitrary code, install backdoors, or access sensitive data within Splunk.
If Mitigated
With proper access controls and monitoring, exploitation attempts would be detected and blocked before successful execution.
🎯 Exploit Status
Requires authenticated access with any non-admin, non-power user role. Exploitation involves file upload to specific directory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Splunk Enterprise: 9.3.3, 9.2.5, 9.1.8. Splunk Cloud Platform: 9.3.2408.104, 9.2.2406.108, 9.2.2403.114, 9.1.2312.208 or later.
Vendor Advisory: https://advisory.splunk.com/advisories/SVD-2025-0301
Restart Required: No
Instructions:
1. Backup your Splunk configuration. 2. Download the appropriate patch from Splunk's downloads page. 3. Follow Splunk's upgrade documentation for your version. 4. Verify the upgrade completed successfully.
🔧 Temporary Workarounds
Restrict access to apptemp directory
allSet strict file permissions on $SPLUNK_HOME/var/run/splunk/apptemp to prevent unauthorized writes.
chmod 750 $SPLUNK_HOME/var/run/splunk/apptemp
chown splunk:splunk $SPLUNK_HOME/var/run/splunk/apptemp
Review and restrict user roles
allAudit all user accounts and ensure only trusted users have any access. Consider removing or disabling low-privileged accounts.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Splunk servers from critical systems.
- Enable detailed audit logging for all file operations in $SPLUNK_HOME/var/run/splunk/apptemp and monitor for suspicious activity.
🔍 How to Verify
Check if Vulnerable:
Check Splunk version via web interface (Settings > Server Info) or command line. Compare against affected versions list.Check Version:
$SPLUNK_HOME/bin/splunk versionVerify Fix Applied:
Verify version is at or above patched versions. Test that low-privileged users cannot write to $SPLUNK_HOME/var/run/splunk/apptemp.📡 Detection & Monitoring
Log Indicators:
- Unauthorized file writes to $SPLUNK_HOME/var/run/splunk/apptemp directory
- Suspicious process execution from apptemp location
- Failed authorization attempts for file upload operations
Network Indicators:
- Unusual outbound connections from Splunk server following file uploads
- Unexpected network traffic to/from Splunk server on non-standard ports
SIEM Query:
index=* sourcetype=splunkd (file_path="*apptemp*" AND action=write) NOT user="admin" NOT user="power"