CVE-2023-22932
📋 TL;DR
This vulnerability allows attackers to inject malicious scripts into Splunk Web views through Base64-encoded image error messages. When exploited, it enables cross-site scripting attacks that can steal session cookies, redirect users, or perform actions on their behalf. Only Splunk Enterprise 9.0 installations with Splunk Web enabled are affected.
💻 Affected Systems
- Splunk Enterprise
📦 What is this software?
Splunk by Splunk
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator session cookies, gain full control of the Splunk instance, access sensitive data, and pivot to other systems in the network.
Likely Case
Attackers steal user session cookies to impersonate legitimate users, access their data, and perform unauthorized actions within Splunk.
If Mitigated
With proper network segmentation and access controls, impact is limited to the Splunk instance itself without lateral movement.
🎯 Exploit Status
Exploitation requires user interaction (viewing a maliciously crafted page) but the XSS payload execution is straightforward once delivered.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.0.4 or later
Vendor Advisory: https://advisory.splunk.com/advisories/SVD-2023-0202
Restart Required: Yes
Instructions:
1. Download Splunk Enterprise 9.0.4 or later from Splunk website. 2. Stop Splunk services. 3. Install the update following Splunk's upgrade documentation. 4. Restart Splunk services.
🔧 Temporary Workarounds
Disable Splunk Web
allTemporarily disable Splunk Web interface to prevent exploitation
Edit web.conf and set 'startwebserver = false'
Restart Splunk
Restrict Network Access
allLimit access to Splunk Web to trusted IP addresses only
Configure firewall rules to restrict port 8000/tcp access
Use network ACLs or security groups
🧯 If You Can't Patch
- Implement strict Content Security Policy headers to prevent script execution
- Deploy WAF rules to detect and block XSS payloads in image error parameters
🔍 How to Verify
Check if Vulnerable:
Check Splunk version via web interface or CLI. If version is 9.0.0, 9.0.1, 9.0.2, or 9.0.3 with Splunk Web enabled, system is vulnerable.Check Version:
$SPLUNK_HOME/bin/splunk versionVerify Fix Applied:
Verify Splunk version is 9.0.4 or higher. Check that Base64 image error messages are properly sanitized.📡 Detection & Monitoring
Log Indicators:
- Unusual Base64-encoded strings in web access logs
- Multiple failed image loading attempts with script-like content
Network Indicators:
- HTTP requests containing Base64-encoded script tags in image error parameters
- Unusual outbound connections from Splunk server
SIEM Query:
source="*web_access.log*" | search "*base64*" AND ("script" OR "javascript" OR "onerror=")