CVE-2025-20325: Splunk Enterprise Secret Key Disclosure

CVE-2025-20325 Overview

CVE-2025-20325 is an information disclosure vulnerability in Splunk Enterprise and Splunk Cloud Platform. The flaw exposes the search head cluster splunk.secret key through debug logs when administrators enable the SHCConfig log channel at the DEBUG logging level in a clustered deployment. An attacker with local access to log files or administrative access to internal indexes could retrieve the key. The splunk.secret key is used to encrypt sensitive configuration data across search head cluster members, so exposure undermines the confidentiality of stored credentials and secrets. The vulnerability is categorized under [CWE-200: Exposure of Sensitive Information to an Unauthorized Actor].

Critical Impact
Disclosure of the splunk.secret key enables an attacker to decrypt sensitive configuration data protected by that key across the search head cluster.

Affected Products

Splunk Enterprise versions below 9.4.3, 9.3.5, 9.2.7, and 9.1.10
Splunk Cloud Platform versions below 9.3.2411.103, 9.3.2408.113, and 9.2.2406.119
Search head cluster deployments with SHCConfig set to DEBUG logging

Discovery Timeline

2025-07-07 - CVE-2025-20325 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-20325

Vulnerability Analysis

The vulnerability stems from unsafe logging behavior in the Splunk search head clustering subsystem. When an administrator raises the SHCConfig log channel to DEBUG in a clustered deployment, the software writes the splunk.secret key value into log records. Those records are persisted to local log files and forwarded to internal Splunk indexes. Any actor able to read those logs or query the internal indexes can recover the key.

The splunk.secret key protects encrypted passwords, tokens, and other sensitive configuration values shared across search head cluster members. Recovery of the key allows an attacker to decrypt those values offline. Because the exposure requires an operator to enable DEBUG logging and requires access preconditions on the log data, exploitation complexity is elevated.

Root Cause

The root cause is insufficient sanitization of sensitive material written by the SHCConfig log channel. The debug logging path emits the cluster secret in cleartext rather than redacting or omitting it. Any downstream consumer of those logs, including the default internal indexes, inherits the exposure.

Attack Vector

Exploitation requires the DEBUG logging condition to be active and one of two access paths. A local attacker with read access to Splunk log files on a search head can extract the key. Alternatively, an authenticated user with administrative access to Splunk internal indexes can search for and retrieve the value. By default, only the admin role has access to internal indexes, so overly permissive role assignments broaden the exposure. See the Splunk Security Advisory SVD-2025-0709 for vendor details.

Detection Methods for CVE-2025-20325

Indicators of Compromise

Presence of SHCConfig DEBUG entries in $SPLUNK_HOME/var/log/splunk/splunkd.log that contain the splunk.secret value
Search queries against internal indexes (for example _internal) referencing SHCConfig or the secret string from non-admin users
Unexpected reads or copies of the $SPLUNK_HOME/etc/auth/splunk.secret file on cluster members

Detection Strategies

Audit Splunk logging configuration for any SHCConfig log channel set to DEBUG in log.cfg or log-local.cfg
Search _internal for historical events that captured the secret and flag any user activity that retrieved those events
Review role-to-capability mappings to identify non-admin roles granted srchIndexesAllowed = _* or equivalent access to internal indexes

Monitoring Recommendations

Alert on modifications to Splunk logging configuration that raise SHCConfig above INFO
Monitor privileged searches touching _internal and other internal indexes, especially by non-administrative accounts
Track authentication and file-system access to search head hosts using endpoint telemetry to catch offline log exfiltration

How to Mitigate CVE-2025-20325

Immediate Actions Required

Upgrade Splunk Enterprise to 9.4.3, 9.3.5, 9.2.7, 9.1.10, or later; Splunk Cloud Platform customers should confirm they are on 9.3.2411.103, 9.3.2408.113, 9.2.2406.119, or later
Set the SHCConfig log channel back to its default level (INFO) if DEBUG was previously enabled
Rotate the splunk.secret key across the search head cluster and re-encrypt affected secrets following Splunk documentation
Purge or restrict access to any log files and internal index events that captured the key during the exposure window

Patch Information

Splunk addresses the issue in Splunk Enterprise 9.4.3, 9.3.5, 9.2.7, and 9.1.10, and in Splunk Cloud Platform 9.3.2411.103, 9.3.2408.113, and 9.2.2406.119. Refer to the Splunk Security Advisory SVD-2025-0709 for full patch guidance and Cloud rollout status.

Workarounds

Keep the SHCConfig log channel at INFO or higher; do not enable DEBUG on production clustered deployments
Restrict internal index access to administrator-level roles by reviewing role capabilities per Define roles on the Splunk platform with capabilities
Enforce strict file-system permissions on $SPLUNK_HOME/var/log/splunk/ so only the Splunk service account can read log files
Follow the vendor guide to Set a security key for the search head cluster after rotation

bash

# Verify the SHCConfig log channel is not set to DEBUG
grep -i "SHCConfig" $SPLUNK_HOME/etc/log.cfg $SPLUNK_HOME/etc/log-local.cfg

# Reset the channel to INFO at runtime
$SPLUNK_HOME/bin/splunk set log-level SHCConfig -level INFO -auth admin:<password>

# Restrict access to the splunk.secret file
chmod 400 $SPLUNK_HOME/etc/auth/splunk.secret
chown splunk:splunk $SPLUNK_HOME/etc/auth/splunk.secret