T09 · Insecure Skill Coding Practices
Error
- Location
scripts/relay-send.cjs:42- Finding
Relay credentials and message contents are transmitted over unauthenticated plaintext TCP
- Content
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{ sock.write(frame({ v: 1, type: 'HELLO', id: `${AGENT}-${Date.now()}`, ts: Date.now(), payload: { agent: AGENT, version: '1.0.0', authToken: TOKEN } })); }); const dec = new Decoder(); sock.on('data', (data) => { for (const f of dec.push(data)) { if (f.type === 'WELCOME') { sock.write(frame({ v: 1, type: 'SEND', id: `m-${Date.now()}`, ts: Date.now(), to: TO, payload: { kind: 'message', body: BODY } })); console.log(JSON.stringify({ ok: true, to: TO, body: BODY })); ``` The corresponding documentation explicitly identifies the transport as TCP: ```markdown **Protocol:** TCP, 4-byte big-endian length prefix + JSON payload (legacy framing) ``` ### Technical Analysis The script uses Node.js `net.createConnection`, which establishes a raw TCP connection without TLS encryption or server authentication. The initial `HELLO` frame contains the relay authentication token, while the subsequent `SEND` frame contains the recipient and message body. Consequently, any party able to observe or alter traffic between the client and relay can read the token and message, modify frames, or impersonate the relay. The destination is also configurable through `--host` and `X402_RELAY_HOST`, so a configuration error or manipulated invocation can send the credential directly to an attacker-controlled server. Network communication is necessary for the declared relay functionality, but transmitting reusable credentials and message contents without transport protection is not the minimum safe privilege required. ### Attack Path 1. A user invokes the relay script with a valid relay token. 2. The script opens a plaintext TCP connec ...[truncated 963 chars]- Remediation
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