CVE-2021-41127
📋 TL;DR
CVE-2021-41127 is a path traversal vulnerability in Rasa's model loading functionality that allows attackers to overwrite or replace bot files by crafting malicious model.tar.gz archives. This affects Rasa instances that load untrusted model files, potentially compromising bot functionality and data integrity. Users of affected Rasa versions are vulnerable if they process model files from untrusted sources.
💻 Affected Systems
- Rasa Open Source
📦 What is this software?
Rasa by Rasa
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of Rasa instance through arbitrary file write leading to remote code execution, data corruption, or service disruption.
Likely Case
Bot file manipulation causing service degradation, data loss, or unauthorized configuration changes.
If Mitigated
Limited impact with proper access controls and trusted model sources only.
🎯 Exploit Status
Exploitation requires ability to upload or provide model files to the Rasa instance.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.8.10
Vendor Advisory: https://github.com/RasaHQ/rasa/security/advisories/GHSA-4365-fhm5-qcrx
Restart Required: Yes
Instructions:
1. Update Rasa using pip: 'pip install rasa==2.8.10' 2. Restart all Rasa services 3. Verify version with 'rasa --version'
🔧 Temporary Workarounds
Restrict model file sources
allOnly load model files from trusted, verified sources and implement strict access controls on model upload endpoints.
Implement file validation
allAdd validation checks for model files before processing, including path traversal detection.
🧯 If You Can't Patch
- Implement strict access controls on CLI and API endpoints that accept model files
- Only process model files from trusted, verified sources and implement file integrity checks
🔍 How to Verify
Check if Vulnerable:
Check Rasa version with 'rasa --version'. If version is below 2.8.10, system is vulnerable.Check Version:
rasa --versionVerify Fix Applied:
Run 'rasa --version' and confirm version is 2.8.10 or higher.📡 Detection & Monitoring
Log Indicators:
- Unusual model file loading patterns
- File write operations outside expected bot directories
- Errors in model loading process
Network Indicators:
- Unexpected model file uploads to Rasa endpoints
- Large or unusual file transfers to model endpoints
SIEM Query:
source="rasa" AND (event="model_load" OR event="file_write") AND path="*../*"