@imqueue/http-protect

Implements simple HTTP traffic protection middleware for node-based express-like web-servers to detect and block abnormal activity on a server from a detected IP sources.

Simple configuration allows to set desired limit on number of requests per given time period and define the blacklist threshold for the users which are by exceeding the limit continue to send requests to the server.

The service protected by this module may be configured on a code level or by setting environment variables.

Requirements

• redis server

Installation

npm i @imqueue/http-protect

Usage

import HttpProtect from '@imqueue/http-protect';

app.use(new HttpProtect().jsonMiddleware());

Or it is possible to do manual injection:

import HttpProtect, { VerificationStatus } from '@imqueue/http-protect';

// inside some async function in the code
const protect = new HttpProtect();
const { status, httpCode } = await protect.verify(req);

switch (status) {
    case VerificationStatus.LIMITED: {
        // user us reached request limit, but not blacklisted yet.
        // warn about abnormal usage
        break;
    }
    case VerificationStatus.BANNED: {
        // bad traffic source, requests must be banned
        break;
    }
    default: {
        // good request, safe to go
        break;
    }
}

This module aldo provides simple API to check if given IP is blacklisted or not, or get the list of banned network addresses:

import HttpProtect from '@imqueue/http-protect';

const protect = new HttpProtect();

// get the list of banned networks
console.log(protect.bannedNetworks().toJSON());

// check if given IP is currently banned or not
console.log(protect.isBanned('127.0.0.1'));

// check if given IP is currently limited or not
console.log(protect.isLimited('127.0.0.1'));

This module uses redis server to deal with requests counters and banned networks. It also based on ioredis module to connect to redis server, so you might want to configure it via constructor options or bypass existing ioredis instance in the options. Please, refer HttpProtectOptions interface for more details.

Client IP resolution

By default the client IP is resolved with request-ip, which reads the usual proxy headers (x-forwarded-for, x-real-ip, etc.). Because bans and rate limits are keyed by this address, a client behind an untrusted proxy could spoof those headers to evade limits or poison the ban list. When the service is exposed behind proxies you do not fully control, override the resolver with a trust-aware one (for example built on top of proxy-addr configured with your known proxies):

import proxyaddr from 'proxy-addr';

const protect = new HttpProtect({
    // trust only your known load balancer subnet
    getClientIp: req => proxyaddr(req, ip => ip === '10.0.0.1'),
});

License

This project is licensed under the GNU General Public License v3.0. See the LICENSE

Happy Coding!