CVE-2025-55796
📋 TL;DR
This vulnerability allows remote attackers to brute-force predictable MD5 tokens used for critical user workflows like password resets and email confirmations. Attackers can guess valid tokens within a small time window, potentially leading to unauthorized account access and takeover. All users of the openml.org web application version v2.0.20241110 are affected.
💻 Affected Systems
- openml.org web application
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete account takeover through unauthorized password resets and email changes, leading to data exposure, privilege escalation, and potential lateral movement within the platform.
Likely Case
Targeted account compromise of specific users through automated brute-force attacks on password reset and email confirmation workflows.
If Mitigated
Limited impact with proper rate limiting, monitoring, and multi-factor authentication in place, though the fundamental vulnerability remains.
🎯 Exploit Status
Exploitation requires only basic scripting knowledge to brute-force tokens within the predictable time window.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check GitHub security advisory for latest patched version
Vendor Advisory: https://github.com/openml/openml.org/security/advisories/GHSA-xfjh-gf9p-8qr6
Restart Required: Yes
Instructions:
1. Review the GitHub security advisory
2. Update to the latest patched version of openml.org
3. Restart the application service
4. Verify token generation now uses cryptographically secure random values
🔧 Temporary Workarounds
Implement rate limiting
allAdd strict rate limiting on token validation endpoints to prevent brute-force attacks
# Configure web server rate limiting (example for nginx)
limit_req_zone $binary_remote_addr zone=tokenlimit:10m rate=10r/m;
location /api/token-validation {
limit_req zone=tokenlimit burst=5 nodelay;
}
Add monitoring for failed token attempts
linuxMonitor and alert on excessive failed token validation attempts
# Example log monitoring rule
grep -i 'invalid.*token' /var/log/application.log | wc -l
🧯 If You Can't Patch
- Implement web application firewall rules to block suspicious token validation patterns
- Enable multi-factor authentication for all user accounts to add additional protection layer
🔍 How to Verify
Check if Vulnerable:
Check if token generation uses predictable timestamp-based MD5 hashing without user-specific entropyCheck Version:
Check application version in configuration or via API endpointVerify Fix Applied:
Verify token generation now incorporates cryptographically secure random values and user-specific data📡 Detection & Monitoring
Log Indicators:
- Multiple failed token validation attempts from single IP
- Successful token validations with timestamps outside expected window
- Unusual patterns of password reset or email confirmation requests
Network Indicators:
- Bursts of requests to token validation endpoints
- Requests with sequential or predictable token values
SIEM Query:
source="application.log" ("invalid token" OR "token validation failed") | stats count by src_ip | where count > 10