CVE-2018-20325
📋 TL;DR
CVE-2018-20325 is a critical remote code execution vulnerability in the Danijar Hafner definitions Python package. The load() method in definitions/parser.py allows arbitrary Python command execution through unsafe deserialization. Any Python application using this package with untrusted input is affected.
💻 Affected Systems
- Danijar Hafner definitions Python package
📦 What is this software?
Definitions by Definitions Project
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attackers to execute arbitrary commands, install malware, exfiltrate data, or pivot to other systems.
Likely Case
Remote code execution leading to data theft, service disruption, or unauthorized system access.
If Mitigated
Limited impact if input validation and sandboxing prevent untrusted data from reaching vulnerable function.
🎯 Exploit Status
Simple proof-of-concept exists in GitHub issues. Exploitation requires sending malicious serialized data to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in updated package versions
Vendor Advisory: https://github.com/danijar/definitions/issues/14
Restart Required: No
Instructions:
1. Update definitions package to patched version. 2. Replace vulnerable load() method calls with safe alternatives. 3. Test application functionality.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation to reject untrusted serialized data before it reaches load() method.
Replace load() with safe_load()
allModify code to use safe_load() instead of load() where possible to prevent arbitrary code execution.
Replace: data = parser.load(input)
With: data = parser.safe_load(input)
🧯 If You Can't Patch
- Network segmentation to isolate vulnerable systems
- Implement strict input validation and whitelisting for all data processed by definitions package
🔍 How to Verify
Check if Vulnerable:
Check if application imports definitions package and uses load() method with potentially untrusted input.Check Version:
pip show definitions | grep VersionVerify Fix Applied:
Verify package version is updated and load() method is no longer used with untrusted data.📡 Detection & Monitoring
Log Indicators:
- Unusual Python module imports
- Suspicious process execution from Python scripts
- Errors from definitions parser
Network Indicators:
- Unexpected outbound connections from application servers
- Traffic patterns suggesting data exfiltration
SIEM Query:
source="application.log" AND "definitions" AND "load()" AND ("pickle" OR "yaml.load")