filecoin-pin: Unbounded DAG pinning can exhaust server resources

The Helia node created for each pin has no bootstrap or mDNS configuration (src/create-pinning-helia.ts:57). A public CID alone may therefore not be fetchable unless the node can reach a content source. In practice, the API also accepts origins, so an attacker can supply a reachable attacker-controlled libp2p origin that serves a large DAG and cause the server to retrieve it.

Impact

Successful exploitation affects availability:

• ■Disk exhaustion from unbounded CAR files in carStoragePath.
• ■Network exhaustion from recursive Bitswap retrieval.
• ■CPU and memory pressure from concurrent libp2p/Helia pin operations.
• ■Service degradation or process failure for other users of the daemon.
• ■Operational cost and manual recovery burden from large partial CAR files.

The default daemon configuration reduces exposure because the server binds to localhost and refuses to start without an access token unless ALLOW_NO_AUTH=true. The finding is most significant when the daemon is exposed beyond localhost, when the token is shared across untrusted users, or when the no-auth mode is enabled.

PoC

curl -X POST "https://target.example/pins" \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "cid": "CID_OF_LARGE_DAG",
    "origins": ["/ip4/203.0.113.10/tcp/4001/p2p/ATTACKER_PEER_ID"],
    "meta": { "purpose": "resource-exhaustion-validation" }
  }'

Submitting many such requests concurrently accelerates resource pressure because each request schedules independent background processing.