CVE-2024-39031
📋 TL;DR
This is a stored cross-site scripting (XSS) vulnerability in Silverpeas Core's calendar feature. An authenticated user can inject malicious scripts into event titles and descriptions, which execute automatically when invited users view their profiles. All users of affected Silverpeas instances are potentially vulnerable to session hijacking or credential theft.
💻 Affected Systems
- Silverpeas Core
📦 What is this software?
Silverpeas by Silverpeas
⚠️ Risk & Real-World Impact
Worst Case
Administrator account compromise leading to full system takeover, data exfiltration, or ransomware deployment.
Likely Case
Session hijacking of regular users, credential theft, or unauthorized actions performed in victims' contexts.
If Mitigated
Limited impact due to proper input validation and output encoding preventing script execution.
🎯 Exploit Status
Exploit requires authenticated user access. Public proof-of-concept demonstrates the injection technique.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.3.6 or later
Vendor Advisory: https://www.github.com/Silverpeas/Silverpeas-Core/pull/1346
Restart Required: Yes
Instructions:
1. Upgrade Silverpeas Core to version 6.3.6 or later. 2. Restart the Silverpeas application server. 3. Verify the fix by testing XSS payloads in event fields.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation to sanitize event title and description fields
Configure web application firewall rules to block script tags in POST requests to event creation endpoints
Content Security Policy
allImplement strict Content Security Policy headers to prevent script execution
Add 'Content-Security-Policy: default-src 'self'; script-src 'self'' to HTTP headers
🧯 If You Can't Patch
- Disable event creation permissions for non-trusted users in Mes Agendas module
- Implement network segmentation to isolate Silverpeas instances from critical systems
🔍 How to Verify
Check if Vulnerable:
Test by creating an event with <script>alert('XSS')</script> in title/description fields and inviting another userCheck Version:
Check Silverpeas administration panel or application logs for version informationVerify Fix Applied:
Attempt the same XSS payload after patching - script should not execute and should be properly encoded📡 Detection & Monitoring
Log Indicators:
- Unusual event creation patterns
- Script tags in event title/description fields in application logs
Network Indicators:
- POST requests to event creation endpoints containing script tags or JavaScript code
SIEM Query:
source="silverpeas_logs" AND (event_title CONTAINS "<script>" OR event_description CONTAINS "javascript:")