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Insecure encryption algorithm - Anonymous cipher suites

Need​

Secure encryption algorithm for all connections

Context​

  • Usage of TypeScript for statically typed JavaScript development
  • Usage of Express for building web applications and APIs
  • Usage of HTTPS for secure communication over the network
  • Usage of fs for file system operations

Description​

Non compliant code​

import express from 'express';
import https from 'https';
import fs from 'fs';

const app = express();

const options = {
  key: fs.readFileSync('private-key.pem'),
  cert: fs.readFileSync('public-cert.pem'),
  ciphers: 'aNULL', // Vulnerable: Allows anonymous cipher suites
};

const server = https.createServer(options, app);

app.get('/', (req, res) => {
  res.send('Hello World!');
});

server.listen(3000, () => {
  console.log('Server listening on port 3000');
});

The vulnerability in this code lies in the insecure encryption algorithm being used. Specifically, the ciphers option in the options object is set to 'aNULL', which allows connections with anonymous cipher suites.

Anonymous cipher suites do not require any form of authentication or verification, making them vulnerable to Man-in-the-Middle (MitM) attacks. An attacker can intercept the communication between the client and the server, decrypt the data, and potentially obtain sensitive information.

In this code, the https.createServer function is used to create an HTTPS server with the specified options. However, by allowing anonymous cipher suites through the 'aNULL' value, the server is susceptible to attacks.

To mitigate this vulnerability, it is recommended to use algorithms that are considered cryptographically secure. This involves configuring the ciphers option with a list of secure cipher suites that provide authentication and encryption.

Steps​

  • Update the ciphers option in the options object to use secure cipher suites.
  • Remove the anonymous cipher suites from the list of allowed ciphers.
  • Use algorithms considered cryptographically secure.
  • Generate or obtain a private key and a public certificate from a trusted certificate authority.
  • Replace the 'private-key.pem' and 'public-cert.pem' file paths with the correct paths to the private key and public certificate files.
  • Test the updated code to ensure it is functioning correctly and securely.

Compliant code​

import express from 'express';
import https from 'https';
import fs from 'fs';

const app = express();

const options = {
  key: fs.readFileSync('path/to/private-key.pem'),
  cert: fs.readFileSync('path/to/public-cert.pem'),
  ciphers: 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305', // Updated: Uses secure cipher suites
};

const server = https.createServer(options, app);

app.get('/', (req, res) => {
  res.send('Hello World!');
});

server.listen(3000, () => {
  console.log('Server listening on port 3000');
});

The fixed code addresses the vulnerability by ensuring that the application uses secure encryption algorithms.

First, the code imports the necessary modules: express, https, and fs.

Then, an instance of the express application is created.

The code defines an options object that contains the necessary configuration for the HTTPS server. It specifies the path to the private key and public certificate files using fs.readFileSync. Additionally, the ciphers property is set to a list of secure cipher suites. These cipher suites are considered cryptographically secure and provide strong encryption for secure communication.

Next, the code creates an HTTPS server using the https.createServer method, passing in the options object and the app instance.

A route is defined for the root path ("/") using app.get, which sends a "Hello World!" response.

Finally, the server is set to listen on port 3000 using the server.listen method, and a message is logged to the console indicating that the server is running.

By using secure cipher suites and configuring the HTTPS server correctly, the fixed code ensures that the application is protected against the vulnerability related to insecure encryption algorithms.

References​

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