CVE-2022-32153: Splunk Enterprise Auth Bypass Vulnerability

CVE-2022-32153 Overview

CVE-2022-32153 is a TLS Certificate Validation Bypass vulnerability affecting Splunk Enterprise and Splunk Cloud Platform deployments. The vulnerability exists because Splunk Enterprise peers in versions before 9.0 and Splunk Cloud Platform versions before 8.2.2203 did not validate TLS certificates during Splunk-to-Splunk communications by default. While properly configured Splunk peer communications with valid certificates were not vulnerable, attackers with administrator credentials could exploit this weakness by adding peers without valid certificates. Additionally, connections from misconfigured nodes without valid certificates would not fail by default, creating a significant security gap in distributed Splunk environments.

Critical Impact

Attackers could perform man-in-the-middle attacks on Splunk-to-Splunk communications, potentially intercepting, modifying, or injecting sensitive log data and security telemetry across distributed deployments.

Affected Products

• Splunk Enterprise versions before 9.0
• Splunk Cloud Platform versions before 8.2.2203
• Distributed Splunk deployments with peer-to-peer communications

Discovery Timeline

• June 15, 2022 - CVE-2022-32153 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-32153

Vulnerability Analysis

This vulnerability stems from improper certificate validation (CWE-295) and improper validation of certificate with host mismatch (CWE-297) in Splunk's inter-node communication architecture. The core issue lies in how Splunk Enterprise handles TLS certificate verification during peer-to-peer communications between distributed components such as indexers, search heads, and forwarders.

In vulnerable configurations, the default behavior allows encrypted communications to proceed without verifying that the presented certificate is valid, properly signed by a trusted certificate authority, or matches the expected hostname. This creates a window of opportunity where an attacker positioned on the network could intercept communications between Splunk nodes.

The vulnerability requires network-level access and has high attack complexity due to the need for either administrator credentials or exploitation of misconfigured nodes. However, successful exploitation could result in complete compromise of confidentiality, integrity, and availability of data flowing between Splunk components.

Root Cause

The root cause of CVE-2022-32153 is the absence of mandatory TLS certificate hostname validation in Splunk-to-Splunk communications. By default, Splunk Enterprise did not enforce certificate validation, meaning nodes could establish encrypted connections without verifying the authenticity of peer certificates. This permissive default configuration was compounded by the ability for administrators to add peers without valid certificates, effectively bypassing any security controls that TLS encryption would normally provide.

Attack Vector

The vulnerability is exploitable over the network (AV:N) and requires specific conditions to be met:

1. Man-in-the-Middle Position: An attacker must be positioned to intercept network traffic between Splunk nodes
2. Administrator Access Scenario: An attacker with compromised administrator credentials could intentionally add malicious peers without valid certificates
3. Misconfiguration Exploitation: Attackers could exploit environments where nodes were deployed without proper certificate configuration, as these connections would not fail by default

The attack flow involves either actively inserting a rogue Splunk peer into the distributed environment or passively intercepting communications between nodes that have not been properly configured with certificate validation.

Detection Methods for CVE-2022-32153

Indicators of Compromise

• Unexpected Splunk peer nodes appearing in the distributed environment configuration
• TLS connections between Splunk components using self-signed or invalid certificates
• Anomalous network traffic patterns between Splunk indexers and search heads
• Certificate-related warnings or errors in Splunk internal logs

Detection Strategies

• Monitor Splunk peer configurations for unauthorized additions using Splunk's internal audit logs
• Implement network-based detection for TLS connections with certificate validation failures
• Utilize Splunk's research detections for digital certificate infrastructure issues
• Deploy Splunk's SSL/TLS certificate identification searches to identify weak encryption scenarios

Monitoring Recommendations

• Enable verbose logging for Splunk-to-Splunk communications to capture certificate validation events
• Configure alerts for any peer additions or modifications in the distributed deployment
• Review Splunk's protocol impersonation and weak encryption detection guidance
• Implement SentinelOne Singularity platform for endpoint-level visibility into Splunk node behavior

How to Mitigate CVE-2022-32153

Immediate Actions Required

• Upgrade Splunk Enterprise to version 9.0 or later immediately
• Upgrade Splunk Cloud Platform to version 8.2.2203 or later
• Audit all existing Splunk peer configurations for unauthorized or misconfigured nodes
• Enable TLS hostname validation for all Splunk-to-Splunk communications

Patch Information

Splunk has addressed this vulnerability in Splunk Enterprise version 9.0 and Splunk Cloud Platform version 8.2.2203. Organizations should upgrade to these versions or later and additionally enable TLS certificate hostname validation following Splunk's official TLS configuration guide. The complete security update details are available in the Splunk Security Announcement SVD-2022-0603.

Workarounds

• If immediate patching is not possible, manually verify all peer certificates before adding new nodes to the distributed environment
• Remove any peers that do not present valid, properly-signed TLS certificates
• Implement network segmentation to isolate Splunk-to-Splunk communication channels
• Deploy additional network monitoring to detect suspicious traffic between Splunk nodes

# Configuration example for enabling TLS certificate validation
# In server.conf on each Splunk instance:
[sslConfig]
sslVerifyServerCert = true
sslVerifyServerName = true
sslCommonNameToCheck = <hostname>
caCertFile = /opt/splunk/etc/auth/cacert.pem