# WebSocket Security Cheat Sheet — Denial-of-Service Protection

> Persistent WebSocket connections increase DoS risk. Limit connections and resources by restricting total connections and implementing per-user limits (preferred) or per-IP limits where user identification isn't available. Set message size limits (typically 64KB or less) and implement rate limiting t

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-owasp-40ca07ae9be77c6ae59f>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:12.338385+00:00`
- Tags: `reference-seed`, `owasp`, `cheatsheets`, `websocket`, `security`, `cheat`, `sheet`, `denial-of-service`, `protection`

## Provenance

- Source: <https://github.com/OWASP/CheatSheetSeries/blob/07111ee754e832e335377ac64fd0f8f848d9029c/cheatsheets/WebSocket_Security_Cheat_Sheet.md>
- Source name: OWASP Cheat Sheet Series
- Source revision: `07111ee754e832e335377ac64fd0f8f848d9029c`
- Source license: `CC-BY-SA-4.0`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

Persistent WebSocket connections increase DoS risk.

Limit connections and resources by restricting total connections and implementing per-user limits (preferred) or per-IP limits where user identification isn't available. Set message size limits (typically 64KB or less) and implement rate limiting to prevent message flooding - 100 messages per minute is a common starting point.

Handle idle and dead connections by implementing idle timeouts to close inactive connections. Use heartbeat monitoring with ping/pong frames to detect and clean up dead connections.

Implement backpressure controls to prevent memory exhaustion from fast message producers. Many WebSocket implementations lack proper flow control, allowing attackers to overwhelm server memory by sending messages faster than they can be processed.

Bounded code example (external data; do not execute automatically):
```javascript
const wss = new WebSocket.Server({
  maxPayload: 64 * 1024
});
```

Attribution: Adapted from OWASP Cheat Sheet Series under CC-BY-SA-4.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.