CVE-2025-20370
📋 TL;DR
This vulnerability allows authenticated Splunk users with the 'change_authentication' capability to send multiple LDAP bind requests to a specific internal endpoint, causing high CPU usage that can lead to denial of service (DoS). Affected systems include Splunk Enterprise versions below 10.0.1, 9.4.4, 9.3.6, and 9.2.8, and Splunk Cloud Platform versions below specific patch levels.
💻 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
Complete denial of service requiring restart of the Splunk instance, disrupting monitoring, logging, and security operations.
Likely Case
Performance degradation and intermittent service disruption affecting Splunk functionality.
If Mitigated
Minimal impact if proper access controls and monitoring are in place to detect abnormal LDAP activity.
🎯 Exploit Status
Exploitation requires the 'change_authentication' capability, which is typically assigned to administrative roles.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Splunk Enterprise: 10.0.1, 9.4.4, 9.3.6, 9.2.8; Splunk Cloud Platform: 9.3.2411.108, 9.3.2408.118, 9.2.2406.123
Vendor Advisory: https://advisory.splunk.com/advisories/SVD-2025-1005
Restart Required: Yes
Instructions:
1. Backup your Splunk configuration. 2. Download the appropriate patch from Splunk's website. 3. Stop Splunk services. 4. Apply the patch following Splunk's upgrade documentation. 5. Restart Splunk services. 6. Verify the version is updated.
🔧 Temporary Workarounds
Restrict 'change_authentication' capability
allRemove the 'change_authentication' capability from non-essential user roles to limit potential attackers.
Monitor LDAP authentication requests
allImplement monitoring for abnormal LDAP bind request patterns to detect potential exploitation attempts.
🧯 If You Can't Patch
- Review and restrict user roles with 'change_authentication' capability to only essential administrators.
- Implement rate limiting or monitoring for LDAP authentication endpoints to detect and block abuse.
🔍 How to Verify
Check if Vulnerable:
Check Splunk version via web interface or CLI and compare against affected versions. Verify if any users have 'change_authentication' capability.Check Version:
On Splunk server: $SPLUNK_HOME/bin/splunk versionVerify Fix Applied:
Confirm Splunk version is at or above patched versions. Test that users with 'change_authentication' capability cannot trigger excessive LDAP requests.📡 Detection & Monitoring
Log Indicators:
- High frequency of LDAP bind requests from single users
- Unusual CPU spikes on Splunk servers
- Authentication endpoint access logs showing repetitive patterns
Network Indicators:
- Increased traffic to Splunk LDAP authentication endpoints
- Abnormal request patterns to internal Splunk APIs
SIEM Query:
index=_internal source=*splunkd* (LDAP OR authentication) | stats count by user, source | where count > threshold