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The vulnerability in cryptidy arises from the insecure deserialization of user-supplied data using the `pickle.loads()` function within the `aes_decrypt_message` method. The Pickle module is designed to serialize and deserialize Python objects. However, it is inherently unsafe because the deserialization process can instantiate arbitrary objects and execute their `__reduce__` method, which allows for the execution of any Python code. In this case, the `aes_decrypt_message` function takes an encrypted message, decrypts it, and then passes the resulting data directly to `pickle.loads()` without validation. An attacker can craft a malicious payload, encrypt it using the expected AES key, and submit it. When the application decrypts and deserializes this payload, the embedded code is executed within the application’s context, leading to full remote code execution.
Platform: Python
Version: through 1.2.4
Vulnerability : Code Execution
Severity: Moderate
date: 2025-10-31
Prediction: Patch by 2025-11-07
What Undercode Say:
python3 -c "import pickle; pickle.loads(open('malicious.pkl', 'rb').read())"
Example malicious pickle payload
import pickle
import os
class RCE:
def <strong>reduce</strong>(self):
return (os.system, ('whoami', ))
payload = pickle.dumps(RCE())
with open('malicious.pkl', 'wb') as f:
f.write(payload)
How Exploit:
Attacker crafts a malicious serialized object using `pickle.dumps()` that executes code upon deserialization. This object is then encrypted using the application’s known AES key and sent to the vulnerable `aes_decrypt_message` endpoint. The application decrypts the data and passes it to pickle.loads, triggering the execution of the attacker’s code.
Protection from this CVE
Replace `pickle.loads` with a secure serialization format like JSON for handling untrusted data. If Pickle is mandatory, implement integrity checks using digital signatures (HMAC) to ensure the data has not been tampered with before deserialization.
Impact:
Remote Code Execution
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Sources:
Reported By: github.com
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