feat(security): implement rate limiting and helmet security headers

- Add express-rate-limit: login limiter (10 req/15m) and global limiter (100 req/m)
- Add helmet: secure HTTP headers with custom CSP configuration
- Remove manual header settings in favor of helmet

backend/app.js

@@ -2,6 +2,8 @@ import bodyParser from "body-parser";
 import compression from "compression";
 import express from "express";
 import fileUpload from "express-fileupload";
+import helmet from "helmet";
+import { rateLimit } from "express-rate-limit";
 import { isDebugMode } from "./lib/config.js";
 import cors from "./lib/express/cors.js";
 import jwt from "./lib/express/jwt.js";
@@ -36,25 +38,51 @@ if (isDebugMode()) {
 // CORS for everything
 app.use(cors);
 
-// General security/cache related headers + server header
+/**
-app.use((_, res, next) => {
+ * Global Rate Limiter: 100 requests per minute per IP
-	let x_frame_options = "DENY";
+ */
-
+const globalLimiter = rateLimit({
-	if (typeof process.env.X_FRAME_OPTIONS !== "undefined" && process.env.X_FRAME_OPTIONS) {
+	windowMs: 1 * 60 * 1000, // 1 minute
-		x_frame_options = process.env.X_FRAME_OPTIONS;
+	max: 100,
-	}
+	standardHeaders: true,
-
+	legacyHeaders: false,
-	res.set({
+	message: { error: { message: "Too many requests, please try again later." } },
-		"X-XSS-Protection": "1; mode=block",
-		"X-Content-Type-Options": "nosniff",
-		"X-Frame-Options": x_frame_options,
-		"Cache-Control": "no-cache, no-store, max-age=0, must-revalidate",
-		Pragma: "no-cache",
-		Expires: 0,
-	});
-	next();
 });
 
+/**
+ * Login Rate Limiter: 10 requests per 15 minutes per IP
+ */
+const loginLimiter = rateLimit({
+	windowMs: 15 * 60 * 1000, // 15 minutes
+	max: 10,
+	standardHeaders: true,
+	legacyHeaders: false,
+	message: { error: { message: "Too many login attempts, please try again in 15 minutes." } },
+});
+
+/**
+ * Helmet Security Headers
+ */
+app.use(
+	helmet({
+		contentSecurityPolicy: {
+			directives: {
+				defaultSrc: ["'self'"],
+				scriptSrc: ["'self'", "'unsafe-inline'", "'unsafe-eval'"], // unsafe-inline/eval required by some React libs
+				styleSrc: ["'self'", "'unsafe-inline'"],
+				imgSrc: ["'self'", "data:", "https://www.gravatar.com"],
+				connectSrc: ["'self'"],
+				frameAncestors: [process.env.X_FRAME_OPTIONS === "ALLOWALL" ? "*" : "'none'"],
+			},
+		},
+		crossOriginResourcePolicy: { policy: "cross-origin" },
+	}),
+);
+
+// Apply rate limiting
+app.use("/api/tokens", loginLimiter);
+app.use("/api/", globalLimiter);
+
 // Bypass JWT for public authenticated requests mapped by WireGuard IP
 app.use("/wg-public", wgPublicRoutes);
 

backend/package.json

@@ -23,7 +23,9 @@
 		"compression": "^1.8.1",
 		"express": "^5.2.1",
 		"express-fileupload": "^1.5.2",
+		"express-rate-limit": "^7.5.0",
 		"gravatar": "^1.8.2",
+		"helmet": "^8.0.0",
 		"jsonwebtoken": "^9.0.3",
 		"knex": "3.1.0",
 		"liquidjs": "10.24.0",