Threat Model Analysis for expressjs/body-parser

Threat: Large Request Body DoS

Threat: Large Request Body DoS
Description: An attacker sends excessively large HTTP request bodies to the server. body-parser attempts to parse these large bodies into memory, consuming server resources. This can be achieved by automated scripts or manual attacks sending very large payloads.
Impact:
- Server memory exhaustion, leading to application crashes or unresponsiveness.
- CPU exhaustion due to parsing extremely large bodies, significantly slowing down or halting the application.
- Denial of service for legitimate users, rendering the application unavailable.
Affected body-parser component: All parser modules (json, urlencoded, raw, text) are affected as they all parse the request body content.
Risk Severity: High
Mitigation Strategies:
- limit option: Configure the limit option within body-parser middleware (e.g., bodyParser.json({ limit: '100kb' })) to strictly enforce maximum request body sizes.
- Reverse Proxy Limits: Implement request body size limits at the reverse proxy level (e.g., using Nginx's client_max_body_size directive or Apache's LimitRequestBody directive) for an initial layer of defense before requests reach the application.
- Rate Limiting: Implement rate limiting to restrict the number of requests from a single IP address within a given timeframe. This can help mitigate rapid, automated DoS attempts.