CVE-2025-67852
📋 TL;DR
An open redirect vulnerability in Moodle's OAuth login flow allows attackers to redirect authenticated users to malicious websites. This affects all Moodle instances using OAuth authentication. Users could be tricked into visiting phishing sites after legitimate login.
💻 Affected Systems
- Moodle
📦 What is this software?
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
⚠️ Risk & Real-World Impact
Worst Case
Users redirected to sophisticated phishing sites that steal credentials or install malware, leading to account compromise and potential data breaches.
Likely Case
Users redirected to phishing pages attempting to harvest login credentials or personal information.
If Mitigated
Users redirected to benign but unexpected external sites, causing confusion but no direct harm.
🎯 Exploit Status
Exploitation requires user interaction (clicking malicious link) but is technically simple once the vulnerability is understood
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Moodle security advisories for specific patched versions
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2025-67852
Restart Required: No
Instructions:
1. Check Moodle security advisories for patched version. 2. Update Moodle to patched version. 3. Verify OAuth redirect validation is properly implemented.
🔧 Temporary Workarounds
Disable OAuth authentication
allTemporarily disable OAuth authentication until patch is applied
Edit Moodle configuration to disable OAuth plugins
Implement redirect validation
allAdd server-side validation to ensure redirect URLs are within allowed domains
Implement whitelist validation for redirect URLs in OAuth flow
🧯 If You Can't Patch
- Implement web application firewall rules to detect and block suspicious redirect patterns
- Educate users about phishing risks and verify URLs before entering credentials
🔍 How to Verify
Check if Vulnerable:
Test OAuth login flow with crafted redirect URLs to external domainsCheck Version:
Check Moodle version in administration panel or via moodle_version tableVerify Fix Applied:
Verify that OAuth redirects only go to approved domains after patch📡 Detection & Monitoring
Log Indicators:
- Unusual redirect patterns in authentication logs
- OAuth requests with external redirect URLs
Network Indicators:
- HTTP 302 redirects to unexpected external domains after authentication
SIEM Query:
Search for authentication events followed by redirects to non-whitelisted domains