ASP.NET MVC Identity login without password

Question

I have been given the assignment of modifying an ASP.NET MVC application in such a way that navigating to myurl?username=xxxxxx automatically logs in user xxxxxx, without asking for a password.

I already made it very clear that this is a terrible idea for many security-related reasons and scenarios, but the people in charge are determined. The site would not be publicly available.

So: is there any way of signing in without a password by, for example, extending the Microsoft.AspNet.Identity.UserManager and modifying the AccountController?

Some code:

var user = await _userManager.FindAsync(model.UserName, model.Password);
if (user != null && IsAllowedToLoginIntoTheCurrentSite(user))
{
    user = _genericRepository.LoadById<User>(user.Id);
    if (user.Active)
    {
        await SignInAsync(user, model.RememberMe);

_userManager holds an instance of a Microsoft.AspNet.Identity.UserManager.

and SignInAsync():

private async Task SignInAsync(User user, bool isPersistent)
{
    AuthenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie);
    var identity = await _userManager.CreateIdentityAsync(user, DefaultAuthenticationTypes.ApplicationCookie);
    if (user.UserGroupId.IsSet())
        user.UserGroup = await _userManager.Load<UserGroup>(user.UserGroupId);

    //adding claims here ... //

    AuthenticationManager.SignIn(
        new AuthenticationProperties { IsPersistent = isPersistent }, 
        new CustomClaimsIdentity(identity));
}

AuthenticationManager would be OwinSecurity.

Answer 1

You just need to use the usermanager to find the user by name. If you have a record then just sign them in.

    public ActionResult StupidCompanyLogin()
    {

        return View();
    }

    [HttpPost]
    //[ValidateAntiForgeryToken] - Whats the point? F**k security 
    public async Task<ActionResult> StupidCompanyLogin(string name)
    {

        var user = await UserManager.FindByNameAsync(name);

        if (user != null)
        {

            await SignInManager.SignInAsync(user, true, true);
        }

        return View();
    }