Insecure authentication method - NTLM
Need
Secure authentication method - Implement a modern and secure authentication protocol such as OAuth or OpenID Connect to replace the insecure NTLM protocol.
Context
- Usage of TypeScript for type-checking and compiling JavaScript code
- Usage of Express for building web applications and handling HTTP requests
- Usage of express-ntlm for NTLM authentication in Express applications
Description
Non compliant code
import express from 'express';
import ntlm from 'express-ntlm';
const app = express();
app.use(ntlm());
app.get('/', (req, res) => {
if (req.ntlm && req.ntlm.UserName) {
res.send(`Welcome, ${req.ntlm.UserName}!`);
} else {
res.status(401).send('Unauthorized');
}
});
app.listen(3000, () => {
console.log('Server is running on port 3000');
});
The vulnerability in this code is the use of the Legacy NTLM authentication protocol. The code imports the 'express' and 'express-ntlm' modules and sets up an Express application.
The vulnerable part of the code is the line app.use(ntlm()), which enables the NTLM authentication middleware provided by the 'express-ntlm' module. This means that any incoming requests to the application will be processed by the NTLM authentication middleware.
In the route handler for the root path '/', the code checks if the req.ntlm object exists and if it has a UserName property. If it does, it sends a welcome message with the username. Otherwise, it sends a 401 Unauthorized response.
The vulnerability lies in the use of the NTLM authentication protocol. NTLM is an older and less secure authentication method that is susceptible to various security flaws, including Relay attacks, Man-in-the-Middle attacks, and brute force attacks.
These vulnerabilities can allow an attacker to intercept and manipulate the authentication process, potentially obtaining valid challenge results and impersonating legitimate application users. This can lead to unauthorized access to sensitive information or actions on behalf of the compromised user.
To mitigate this vulnerability, it is recommended to avoid and restrict the use of NTLM as an authentication mechanism. Instead, more recent and secure alternatives such as Kerberos, Smart Cards, OAuth, Bearer Authentication, forms, JWT, among others, should be used.
Steps
- Replace the use of NTLM authentication with a more secure authentication mechanism.
- Consider using modern authentication protocols such as OAuth, Bearer Authentication, or JWT.
- Remove the 'express-ntlm' package dependency.
- Update the code to use the new authentication mechanism.
- Ensure that the new authentication mechanism is properly implemented and secure.
- Test the application thoroughly to verify the functionality and security of the new authentication mechanism.
- Monitor and log authentication events to detect any suspicious activity.
Compliant code
import express from 'express';
const app = express();
app.use(express.json());
app.post('/login', (req, res) => {
const { username, password } = req.body;
// Implement your secure authentication mechanism here
// Example: verify username and password against a secure database
if (username === 'admin' && password === 'password') {
// Generate a secure token or session ID
const token = generateToken();
// Return the token to the client
res.json({ token });
} else {
res.status(401).json({ error: 'Unauthorized' });
}
});
app.get('/', (req, res) => {
const token = req.headers.authorization;
// Implement your token verification logic here
// Example: verify the token against a secure database
if (token === 'valid_token') {
// Get the user information associated with the token
const user = getUserFromToken(token);
res.send(`Welcome, ${user.username}!`);
} else {
res.status(401).json({ error: 'Unauthorized' });
}
});
app.listen(3000, () => {
console.log('Server is running on port 3000');
});
function generateToken() {
// Implement your token generation logic here
// Example: use a secure library to generate a random token
return 'valid_token';
}
function getUserFromToken(token) {
// Implement your token verification logic here
// Example: query the database to get the user information associated with the token
return { username: 'admin' };
}
The fixed code is written in TypeScript and uses the Express framework to handle HTTP requests. It addresses the vulnerability by implementing a secure authentication mechanism instead of using the insecure NTLM protocol.
The code starts by importing the necessary modules and creating an instance of the Express application. It then adds middleware to parse JSON data in the request body.
The /login route is defined as a POST request handler. It expects the client to send a JSON object containing a username and password. The code should be modified to implement a secure authentication mechanism, such as verifying the credentials against a secure database. In the example code, it checks if the username is 'admin' and the password is 'password'. If the credentials are valid, it generates a secure token using the generateToken function and sends it back to the client as a JSON response.
The / route is defined as a GET request handler. It expects the client to send the token in the Authorization header. The code should be modified to implement a secure token verification logic, such as checking the token against a secure database. In the example code, it checks if the token is 'valid_token'. If the token is valid, it retrieves the user information associated with the token using the getUserFromToken function and sends a welcome message to the client.
The server is set to listen on port 3000, and a console log message is printed to indicate that the server is running.
The generateToken function is a placeholder and should be replaced with a secure token generation logic, such as using a secure library to generate a random token.
The getUserFromToken function is also a placeholder and should be replaced with a secure token verification logic, such as querying a secure database to retrieve the user information associated with the token.
Overall, the code demonstrates the use of secure authentication mechanisms, such as verifying credentials and using secure tokens, to mitigate the vulnerability of insecure authentication methods like NTLM.