CVE-2023-23937
📋 TL;DR
This vulnerability allows authenticated users to bypass file upload validation in Pimcore by adding a fake GIF signature to malicious files. Attackers can upload HTML files containing JavaScript that executes in the domain context, potentially leading to cross-site scripting attacks. All Pimcore installations with user upload functionality are affected.
💻 Affected Systems
- Pimcore
📦 What is this software?
Pimcore by Pimcore
⚠️ Risk & Real-World Impact
Worst Case
Authenticated attacker uploads malicious HTML/JS files that execute in domain context, leading to session hijacking, account takeover, or malware distribution to other users.
Likely Case
Authenticated user uploads malicious scripts that execute when viewed by other users, enabling cross-site scripting attacks and potential data theft.
If Mitigated
With proper input validation and content-type checking, malicious uploads are blocked, limiting impact to failed upload attempts.
🎯 Exploit Status
Exploitation requires authenticated access but is technically simple once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.5.16
Vendor Advisory: https://github.com/pimcore/pimcore/security/advisories/GHSA-8xv4-jj4h-qww6
Restart Required: No
Instructions:
1. Update Pimcore to version 10.5.16 or later. 2. Apply the patch from the GitHub commit. 3. Verify the fix by testing file upload functionality.
🔧 Temporary Workarounds
Disable user profile uploads
allTemporarily disable the vulnerable upload functionality until patching is complete.
Modify Pimcore configuration to disable user profile file uploads
Implement WAF rules
allAdd web application firewall rules to block suspicious file uploads with mismatched content types.
Configure WAF to inspect Content-Type headers and file signatures
🧯 If You Can't Patch
- Implement strict file upload validation at the application layer
- Restrict user upload permissions to trusted users only
🔍 How to Verify
Check if Vulnerable:
Check if Pimcore version is below 10.5.16 and test if file upload accepts files with mismatched content-type and file signatures.Check Version:
Check Pimcore version in admin panel or via composer show pimcore/pimcoreVerify Fix Applied:
After updating to 10.5.16+, test that file uploads with mismatched content-type and signatures are rejected.📡 Detection & Monitoring
Log Indicators:
- Multiple failed upload attempts with different content types
- Uploads of files with .html extension via profile update
Network Indicators:
- HTTP POST requests to upload endpoints with mismatched Content-Type headers
SIEM Query:
source="pimcore" AND (event="file_upload" AND (file_extension=".html" OR content_type!="image/gif"))🔗 References
- https://github.com/pimcore/pimcore/commit/75a448ef8ac74424cf4e723afeb6d05f9eed872f
- https://github.com/pimcore/pimcore/security/advisories/GHSA-8xv4-jj4h-qww6
- https://github.com/pimcore/pimcore/commit/75a448ef8ac74424cf4e723afeb6d05f9eed872f
- https://github.com/pimcore/pimcore/security/advisories/GHSA-8xv4-jj4h-qww6
