CVE-2023-32707: Splunk Enterprise Privilege Escalation Flaw

CVE-2023-32707 Overview

CVE-2023-32707 is a privilege escalation vulnerability affecting Splunk Enterprise and Splunk Cloud Platform. In versions of Splunk Enterprise below 9.0.5, 8.2.11, and 8.1.14, and Splunk Cloud Platform below version 9.0.2303.100, a low-privileged user who holds a role that has the edit_user capability assigned to it can escalate their privileges to that of the admin user by providing specially crafted web requests.

Critical Impact

A low-privileged attacker with the edit_user capability can escalate to full administrative privileges, potentially gaining complete control over the Splunk deployment and access to all indexed data.

Affected Products

• Splunk Enterprise versions below 9.0.5
• Splunk Enterprise versions below 8.2.11
• Splunk Enterprise versions below 8.1.14
• Splunk Cloud Platform versions below 9.0.2303.100

Discovery Timeline

• 2023-06-01 - CVE-2023-32707 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-32707

Vulnerability Analysis

This vulnerability stems from improper authorization controls (CWE-285) within Splunk's user management functionality. The edit_user capability, which is intended to allow certain administrative functions related to user account management, does not properly restrict the scope of modifications that can be made. Specifically, a user possessing only this limited capability can craft malicious web requests to modify user attributes beyond their intended authorization scope, including elevating their own role to administrator.

The attack is network-accessible and requires only low privileges (the edit_user capability), making it relatively straightforward to exploit once an attacker has obtained initial access with a role containing this capability. No user interaction is required for successful exploitation.

Root Cause

The root cause is improper authorization (CWE-285) in Splunk's user management API endpoints. The application fails to adequately verify that users with the edit_user capability are only modifying user attributes within their permitted scope. This missing authorization check allows privilege boundaries to be bypassed, enabling horizontal and vertical privilege escalation through role manipulation.

Attack Vector

The attack is conducted over the network through specially crafted HTTP requests to Splunk's web interface or REST API. An attacker who has compromised or created an account with the edit_user capability can:

1. Authenticate to the Splunk instance with their low-privileged account
2. Craft malicious web requests targeting user management endpoints
3. Modify their own user account or create new accounts with elevated privileges
4. Gain full administrative access to the Splunk deployment

The vulnerability exploits the trust placed in users with the edit_user capability without proper boundary enforcement on what user attributes can be modified.

Detection Methods for CVE-2023-32707

Indicators of Compromise

• Unexpected changes to user roles, particularly elevations to admin or power user roles
• Audit log entries showing role modifications by users who should not have that level of access
• New admin accounts created by non-administrative users
• Unusual REST API calls to /services/authentication/users endpoints from low-privileged accounts

Detection Strategies

• Monitor Splunk's internal audit logs for suspicious user modification activities using Splunk's own SIEM capabilities
• Review the _audit index for events related to user role changes and privilege modifications
• Implement alerts for any role changes involving administrative capabilities
• Utilize the Splunk Research detection content specifically designed for this vulnerability

Monitoring Recommendations

• Enable verbose audit logging for all user management operations in Splunk
• Create correlation searches to detect privilege escalation patterns
• Monitor for multiple rapid user modification requests from the same source
• Implement role-based access control reviews to identify accounts with unnecessary edit_user capability

How to Mitigate CVE-2023-32707

Immediate Actions Required

• Upgrade Splunk Enterprise to version 9.0.5, 8.2.11, or 8.1.14 or later depending on your release branch
• For Splunk Cloud Platform, ensure you are running version 9.0.2303.100 or later
• Audit all roles to identify which have the edit_user capability assigned
• Remove edit_user capability from roles where it is not strictly necessary
• Review user accounts for any unauthorized privilege changes

Patch Information

Splunk has released patches addressing this vulnerability. Organizations should upgrade to the following versions:

• Splunk Enterprise 9.0.x: Upgrade to version 9.0.5 or later
• Splunk Enterprise 8.2.x: Upgrade to version 8.2.11 or later
• Splunk Enterprise 8.1.x: Upgrade to version 8.1.14 or later
• Splunk Cloud Platform: Upgrade to version 9.0.2303.100 or later

For detailed patch information, refer to the Splunk Security Advisory SVD-2023-0602.

Workarounds

• Remove the edit_user capability from all non-essential roles until patching is complete
• Implement network segmentation to restrict access to Splunk management interfaces
• Enable multi-factor authentication to reduce the risk of account compromise
• Monitor for exploitation attempts using Splunk's built-in security monitoring capabilities

# Review roles with edit_user capability in Splunk CLI
splunk btool authorize list --debug | grep -A 10 "edit_user"

# Disable edit_user capability for a specific role (example)
# Edit $SPLUNK_HOME/etc/system/local/authorize.conf
# Remove or comment out 'edit_user = enabled' from affected roles