CVE-2021-40849
📋 TL;DR
This vulnerability allows attackers to exploit web services tokens in Mahara to log into associated accounts without proper authentication. This affects all Mahara installations running vulnerable versions, potentially exposing user data and system access. The flaw enables unauthorized access that can lead to information disclosure and privilege escalation.
💻 Affected Systems
- Mahara
📦 What is this software?
Mahara by Mahara
Mahara by Mahara
Mahara by Mahara
Mahara by Mahara
Mahara by Mahara
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise where attackers gain administrative access, exfiltrate all user data, modify or delete content, and potentially use the system as a foothold for further attacks.
Likely Case
Unauthorized access to user accounts leading to information disclosure, data theft, and potential privilege escalation within the Mahara platform.
If Mitigated
Limited impact with proper network segmentation, strong authentication controls, and monitoring in place, though the vulnerability still exists.
🎯 Exploit Status
Exploitation requires access to web services tokens but does not require authentication to the Mahara system itself. The vulnerability is in the authentication mechanism.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 20.04.5, 20.10.3, 21.04.2, or 21.10.0
Vendor Advisory: https://mahara.org/interaction/forum/topic.php?id=8949
Restart Required: No
Instructions:
1. Backup your Mahara installation and database. 2. Download the appropriate patched version from the Mahara website. 3. Replace the vulnerable files with the patched version. 4. Clear any caches if applicable. 5. Verify the fix by testing authentication.
🔧 Temporary Workarounds
Disable Web Services
allTemporarily disable Mahara web services to prevent exploitation of the token vulnerability
Edit Mahara configuration to disable web services functionality
Restrict Network Access
allLimit access to Mahara web services endpoints to trusted IP addresses only
Configure firewall rules to restrict access to Mahara web services ports
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Mahara instances from untrusted networks
- Enable detailed logging and monitoring for authentication attempts and web services access
🔍 How to Verify
Check if Vulnerable:
Check your Mahara version against the vulnerable versions list. If running a version before the patched versions, you are vulnerable.Check Version:
Check the Mahara admin interface or config.php file for version informationVerify Fix Applied:
After patching, verify the version shows as 20.04.5, 20.10.3, 21.04.2, or 21.10.0 or later. Test web services authentication to ensure proper token validation.📡 Detection & Monitoring
Log Indicators:
- Unusual authentication patterns
- Multiple failed login attempts followed by successful login via web services
- Access from unexpected IP addresses to web services endpoints
Network Indicators:
- Unusual traffic patterns to Mahara web services endpoints
- Authentication requests without proper session establishment
SIEM Query:
source="mahara" AND (event_type="authentication" OR event_type="web_services") AND result="success" | stats count by src_ip, user