CVE-2021-44140
📋 TL;DR
CVE-2021-44140 is a critical vulnerability in Apache JSPWiki that allows remote attackers to delete arbitrary files on the server by sending a specially crafted HTTP request during logout. This affects all JSPWiki instances up to version 2.11.0.M8. Organizations running vulnerable JSPWiki versions are at risk of data loss and system disruption.
💻 Affected Systems
- Apache JSPWiki
📦 What is this software?
Jspwiki by Apache
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through deletion of critical system files, leading to service disruption, data loss, and potential privilege escalation.
Likely Case
Deletion of web application files, configuration files, or user data resulting in service disruption and data loss.
If Mitigated
Limited impact if file permissions restrict JSPWiki user access to sensitive directories.
🎯 Exploit Status
Exploitation requires sending a crafted HTTP request to the logout endpoint. No authentication is required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.11.0 or later
Vendor Advisory: https://jspwiki-wiki.apache.org/Wiki.jsp?page=CVE-2021-44140
Restart Required: Yes
Instructions:
1. Download JSPWiki version 2.11.0 or later from Apache. 2. Backup current installation. 3. Replace with patched version. 4. Restart the JSPWiki service or web server.
🔧 Temporary Workarounds
Disable logout functionality
allTemporarily disable the logout endpoint to prevent exploitation
Modify web.xml to remove or restrict access to logout servlet
Restrict file system permissions
linuxLimit JSPWiki user permissions to only necessary directories
chmod -R 750 /path/to/jspwiki/data
chown -R www-data:www-data /path/to/jspwiki/data
🧯 If You Can't Patch
- Implement strict network access controls to limit access to JSPWiki
- Monitor and alert on file deletion events in JSPWiki directories
🔍 How to Verify
Check if Vulnerable:
Check JSPWiki version in web interface or configuration filesCheck Version:
Check WEB-INF/web.xml or JSPWiki configuration for version informationVerify Fix Applied:
Verify version is 2.11.0 or later and test logout functionality📡 Detection & Monitoring
Log Indicators:
- Unusual logout requests with file paths in parameters
- File deletion events in JSPWiki directories
Network Indicators:
- HTTP POST requests to logout endpoint with suspicious parameters
SIEM Query:
source="jspwiki.log" AND (uri="/logout" OR method="POST") AND (param="*../*" OR param="*..\\*")