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Insufficient data authenticity validation

Need​

Enhanced data authenticity validation and verification

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 {
    
    @IBOutlet weak var nameField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func saveButtonPressed(_ sender: Any) {
        let name = nameField.text
        saveData(name: name)
    }
    
    func saveData(name: String?) {
        // Save the data to the server without validation
    }
}

The above Swift code represents a simple ViewController for an iOS application, where a user enters their name into a text field and presses a save button to send this data to the server.

The vulnerability lies in the saveData(name: String?) function. This function takes the user's input and sends it to the server without any form of validation or permission checks.

This means that an attacker could potentially input any data into the name field, including non-existing names or other invalid data, and the application would accept it without any checks. This could lead to data inconsistency, data corruption, or even security breaches if the input data is used in a harmful way.

Moreover, there's no check to see if the person who is trying to modify the data has the permission to do so. This could allow unauthorized users to modify data they are not supposed to have access to.

The insufficient data authenticity validation vulnerability here could lead to serious implications for the application's data integrity and security.

Steps​

  • Implement server-side validation to ensure that only authorized users can modify certain fields.
  • Validate the data received from the client-side before saving it to the server.
  • Use proper authentication and authorization mechanisms to control access to sensitive data and operations.
  • Implement input validation on the client-side to prevent the submission of invalid data.
  • Consider implementing a whitelist or blacklist approach to validate the data against a predefined set of allowed values.
  • Implement data integrity checks, such as checksums or digital signatures, to ensure the authenticity and integrity of the data.
  • Regularly update and patch the server-side code to address any security vulnerabilities.

Compliant code​

import UIKit

class ViewController: UIViewController {
    
    @IBOutlet weak var nameField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func saveButtonPressed(_ sender: Any) {
        let name = nameField.text
        if validateName(name: name) {
            saveData(name: name)
        } else {
            // Handle invalid name
        }
    }
    
    func validateName(name: String?) -> Bool {
        // Implement your validation logic here
        // For example, check if the name exists in a predefined whitelist
        return true
    }
    
    func saveData(name: String?) {
        // Before saving the data, validate it on the server-side
        // Use proper authentication and authorization mechanisms
        // Implement data integrity checks
    }
}

The updated code includes a new function validateName(name: String?) -> Bool that validates the name before saving it. This function should contain the logic to check if the name exists in a predefined whitelist of allowed values. If the name is valid, the saveData(name: String?) function is called; otherwise, the invalid name is handled appropriately.

In the saveData(name: String?) function, before saving the data, it should be validated on the server-side. This can be done by sending a request to the server and waiting for the response. The server should check if the user is authorized to modify the data and if the data is valid.

Proper authentication and authorization mechanisms should be used to control access to sensitive data and operations. This can be done by using secure tokens or other similar methods.

Data integrity checks should also be implemented to ensure the authenticity and integrity of the data. This can be done by using checksums or digital signatures.

Regularly updating and patching the server-side code is also important to address any security vulnerabilities. This can be done by regularly checking for updates and applying them as soon as they are available.

References​

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