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Authentication mechanism absence or evasion

Need​

Implementation of a robust and secure authentication mechanism

Context​

  • Usage of Swift for iOS and macOS app development
  • Usage of UIKit for building modern and responsive user interfaces

Description​

Non compliant code​

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBAction func accessProtectedResource(_ sender: Any) {
        // Accessing protected resource without any authentication
        let protectedResourceViewController = ProtectedResourceViewController()
        self.present(protectedResourceViewController, animated: true, completion: nil)
    }
}

The above Swift code represents a ViewController in an iOS application. This controller has a function accessProtectedResource(_:) which is triggered when a user tries to access a protected resource.

However, the vulnerability lies in the fact that there is no authentication mechanism in place to verify the identity of the user before granting access to the protected resource. The function simply instantiates the ProtectedResourceViewController and presents it, allowing anyone to access the protected resource without any authentication.

This lack of authentication mechanism or its bypass is a serious security flaw as it can allow unauthorized users to gain access to sensitive data or perform actions they are not permitted to do, potentially leading to data breaches or other serious security incidents.

To fix this vulnerability, an authentication mechanism should be implemented before granting access to the protected resource. This could be in the form of a login screen where users are required to enter their credentials, or a biometric authentication mechanism such as Touch ID or Face ID. Additionally, session management should be implemented to ensure that a user's session remains active only for a certain period of time and gets invalidated after inactivity or logout.

Steps​

  • Implement a secure authentication mechanism.
  • Ensure that all sensitive resources are protected and can only be accessed by authenticated users.
  • Use a secure session management system to track and validate user sessions.
  • Implement proper authorization checks to ensure that only authorized users can access protected resources.
  • Consider using industry-standard authentication protocols and libraries to enhance security.
  • Regularly update and patch the authentication mechanism to address any known vulnerabilities.

Compliant code​

import UIKit

class LoginViewController: UIViewController {
    @IBOutlet weak var usernameTextField: UITextField!
    @IBOutlet weak var passwordTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func loginButtonTapped(_ sender: Any) {
        guard let username = usernameTextField.text, let password = passwordTextField.text else {
            return
        }

        // Implement your authentication logic here
        authenticateUser(username: username, password: password)
    }

    func authenticateUser(username: String, password: String) {
        // This is a placeholder for your authentication logic
        // In a real-world application, you would replace this with code to authenticate the user
        // For example, you might check the username and password against a database or use an authentication service
        if username == "admin" && password == "password" {
            let protectedResourceViewController = ProtectedResourceViewController()
            self.present(protectedResourceViewController, animated: true, completion: nil)
        } else {
            // Handle authentication failure
            print("Authentication failed")
        }
    }
}

The updated code introduces a new LoginViewController that contains two text fields for the user to enter their username and password. When the login button is tapped, the loginButtonTapped(_:) method is called. This method retrieves the entered username and password and passes them to the authenticateUser(username:password:) method.

The authenticateUser(username:password:) method is where the authentication logic should be implemented. In this placeholder implementation, it simply checks if the username is "admin" and the password is "password", and if so, it presents the ProtectedResourceViewController. In a real-world application, this method should be replaced with proper authentication logic, such as checking the credentials against a database or using an authentication service.

If the authentication fails, a message is printed to the console. In a real-world application, you would want to provide feedback to the user, such as displaying an alert or updating the UI to indicate that the login attempt was unsuccessful.

This code ensures that the protected resource can only be accessed by authenticated users, addressing the identified vulnerability.

References​

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