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Insecure encryption algorithm - DSA

Need​

Implementation of a secure encryption algorithm

Context​

  • Usage of Node.js v14.0.0 for server-side JavaScript development
  • Usage of Express for building web applications and APIs
  • Usage of crypto for cryptographic operations

Description​

Non compliant code​

import express from 'express';
import crypto from 'crypto';

const app = express();

app.get('/login', (req, res) => {
  const username = req.query.username;
  const password = req.query.password;

  // Insecure encryption algorithm (DSA)
  const cipher = crypto.createCipher('dsa', 'secretKey');
  let encryptedPassword = cipher.update(password, 'utf8', 'hex');
  encryptedPassword += cipher.final('hex');

  // Store the encrypted password in the database
  // ...

  res.send('Login successful');
});

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

The vulnerability in the provided code lies in the usage of an insecure encryption algorithm, specifically the DSA (Digital Signature Algorithm).

In the code, the crypto.createCipher function is used to create a cipher object with the algorithm set to 'dsa' and a secret key. The createCipher function is part of the Node.js crypto module and is used for symmetric encryption. However, DSA is not a suitable algorithm for encryption purposes. It is primarily used for digital signatures and not designed for confidentiality.

Using an insecure encryption algorithm like DSA can lead to the decryption of the information transmitted between the client and the server. Attackers can potentially exploit this vulnerability to gain unauthorized access to sensitive data, such as passwords or other confidential information.

To address this vulnerability, it is recommended to use algorithms that are considered cryptographically secure, such as AES (Advanced Encryption Standard) or RSA (Rivest-Shamir-Adleman). These algorithms have been extensively tested and are widely accepted as secure for encryption purposes.

Steps​

  • Replace the insecure encryption algorithm (DSA) with a cryptographically secure algorithm such as AES or bcrypt.
  • Generate a secure secret key for the encryption algorithm.
  • Update the code to use the new encryption algorithm and secret key.
  • Ensure that the encrypted password is securely stored in the database.
  • Test the updated code to ensure it functions correctly and securely.

Compliant code​

import express from 'express';
import crypto from 'crypto';

const app = express();

app.get('/login', (req, res) => {
  const username = req.query.username;
  const password = req.query.password;

  // Generate a secure secret key
  const secretKey = crypto.randomBytes(32);

  // Use a cryptographically secure encryption algorithm (AES)
  const cipher = crypto.createCipher('aes-256-cbc', secretKey);
  let encryptedPassword = cipher.update(password, 'utf8', 'hex');
  encryptedPassword += cipher.final('hex');

  // Store the encrypted password securely in the database
  // ...

  res.send('Login successful');
});

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

The fixed code addresses the vulnerability by using a cryptographically secure encryption algorithm (AES) instead of the insecure encryption algorithm (DSA). Here is an explanation of the changes made in the code:

  1. The code imports the necessary modules, including the 'express' module for creating the server and the 'crypto' module for cryptographic operations.

  2. The code creates an instance of the express application using the 'express()' function.

  3. The code defines a route for the '/login' endpoint using the 'app.get()' method. This route handles the login request from the client.

  4. Inside the route handler, the code retrieves the username and password from the request query parameters.

  5. To generate a secure secret key, the code uses the 'crypto.randomBytes()' method to generate a 32-byte random key.

  6. The code creates a cipher object using the 'crypto.createCipher()' method, specifying the 'aes-256-cbc' algorithm and the generated secret key. This ensures that a cryptographically secure encryption algorithm (AES) is used.

  7. The code encrypts the password using the cipher object by calling the 'cipher.update()' method with the password, specifying the input encoding as 'utf8' and the output encoding as 'hex'. The 'cipher.final()' method is then called to obtain the final encrypted password in hexadecimal format.

  8. The code securely stores the encrypted password in the database. The implementation of this step is not shown in the code snippet.

  9. Finally, the code sends a response to the client with the message 'Login successful' using the 'res.send()' method.

  10. The code starts the server on port 3000 by calling the 'app.listen()' method and logs a message to the console when the server starts.

By using a cryptographically secure encryption algorithm (AES) and generating a secure secret key, the fixed code ensures that the transmitted information between the client and the server is encrypted securely, mitigating the vulnerability.

References​

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