Need

Secure user management and access control

Context

• Usage of C# for building robust and scalable applications
• Usage of Microsoft.AspNetCore.Mvc for building web applications with ASP.NET Core
• Usage of Microsoft.AspNetCore.Identity for managing user authentication and authorization in ASP.NET Core applications
• Usage of System.Threading.Tasks for asynchronous programming in .NET

Description

Non compliant code

        public class UserController : Controller
{
    private readonly UserManager _userManager;
    private readonly EmailService _emailService;

    public UserController(UserManager userManager, EmailService emailService)
    {
        _userManager = userManager;
        _emailService = emailService;
    }

    [HttpPost]
    public async Task AssignVulnerabilityManager(string email, Vulnerability vulnerability)
    {
        var user = await _userManager.FindByEmailAsync(email);
        if (user == null)
        {
            // Assigning non-user as vulnerability manager
            _emailService.SendVulnerabilityDetails(email, vulnerability);
            return Ok();
        }

        // Assign user as vulnerability manager
        vulnerability.ManagerId = user.Id;
        _emailService.SendVulnerabilityDetails(email, vulnerability);

        return Ok();
    }
}
        
        

The above code is an example of an insecure functionality vulnerability in a user management system of an ASP.NET Core application.

In this code, there is a UserController class with a AssignVulnerabilityManager method that assigns a user as a manager of a vulnerability. This method takes an email and a vulnerability as parameters. It then finds a user with the provided email using the _userManager.FindByEmailAsync(email) method.

If the user doesn't exist (i.e., user == null), the method sends vulnerability details to the provided email, even if the email is not registered in the system. This is a major security risk as it exposes sensitive vulnerability details to unregistered users.

Moreover, if the user exists, the method assigns the user as the manager of the vulnerability and sends the vulnerability details to the user. However, even if the user is later removed from all the projects of an organization, the vulnerability details and policies are still accessible by the email. This is another security risk as it allows unauthorized access to sensitive information.

Steps

• Validate the email address before assigning it as a vulnerability manager.
• Ensure that the email address belongs to a registered user before sending vulnerability details.
• Remove the ability to send vulnerability details to non-users.
• Implement proper access control to restrict access to vulnerability details based on user permissions.
• Consider removing the ability to assign vulnerability managers by email altogether and use a different method, such as selecting from a list of registered users.

Compliant code

        public class UserController : Controller
{
    private readonly UserManager _userManager;
    private readonly EmailService _emailService;

    public UserController(UserManager userManager, EmailService emailService)
    {
        _userManager = userManager;
        _emailService = emailService;
    }

    [HttpPost]
    public async Task AssignVulnerabilityManager(string email, Vulnerability vulnerability)
    {
        var user = await _userManager.FindByEmailAsync(email);
        if (user == null)
        {
            // User not found, return an error response
            return BadRequest("User not found");
        }

        // Check if user has the necessary permissions
        if (!await _userManager.IsInRoleAsync(user, "VulnerabilityManager"))
        {
            return Forbid();
        }

        // Assign user as vulnerability manager
        vulnerability.ManagerId = user.Id;
        _emailService.SendVulnerabilityDetails(email, vulnerability);

        return Ok();
    }
}
        
        

The updated code now validates the email address before assigning it as a vulnerability manager. If the user is not found, it returns a "Bad Request" response.

Additionally, it checks if the user has the necessary permissions to be assigned as a vulnerability manager. If the user does not have the necessary permissions, it returns a "Forbidden" response.

The ability to send vulnerability details to non-users has been removed. Now, the vulnerability details are only sent to the user if they are found and have the necessary permissions.

This change ensures that only registered users with the necessary permissions can be assigned as vulnerability managers and receive vulnerability details. It also provides proper access control by restricting access to vulnerability details based on user permissions.

References

• 324. Insecure functionality - User management