Is it alright to put sensitive data into the cache? ASP MVC - asp.net

Question

I currently implemented some "checkers" for my MVC application.
So far here is what i have,
Authorization(Form)
Authentication (Custom RoleProvider)
Action Filters(to make sure that the user won't put any bogus id numbers or try accessing the other's data by editing the GET url.
I have several questions regarding the best practices for cache on ASP MVC.
Here is my implementation of my login:
[HttpGet]
[ActionName("login")]
public ActionResult login_load()
{
return View();
}
[HttpPost]
[ActionName("login")]
public ActionResult login_post(string uname,string pword)
{
using (EmployeeContext emp = new EmployeeContext())
{
//h student log = new student();
int success = emp.login.Where(x => x.username == uname && x.password == pword).Count();
if (success == 1)
{
int id = (from logs in emp.login
join rol in emp.roles on logs.role equals rol.id
where logs.username == uname
select logs.id).First();
FormsAuthentication.SetAuthCookie(uname, false);
HttpRuntime.Cache.Insert("id", id);
return RedirectToAction("Details", "Enrollment", new { id = id});
}
return View();
}
}
(I plan on implementing H&S as soon)
Anyway, here are my concerns so far:
For security concerns, would it be fine to store something like id's on cache? or it's better if i use sessions ?
Let's say i successfully logged in, and i add another line of this code :
HttpRuntime.Cache.Insert("id", id);
Is it going to edit my previous record or it's going to add another entry?
I have this code from my Custom RoleProvider, HttpRuntime.Cache.Insert(cacheKey, roles, null, DateTime.Now.AddMinutes(_cacheTimeoutInMinute), Cache.NoSlidingExpiration); and i believe that they are "fired" everytime i ask a controller with a protection of [Authorize(Role="users")]. So does it make a new entry or it edits the previous/existing one?
Should i worry about deleting/clearing my cache as soon as the user decided to log out? my role provider timeout is currently set to 20 minutes
I need the id because aside from the username, it is my unique identifier and i use it to compare on whatever id the user is trying to access.
I am thinking if it would be possible to edit the cache and use it against my application.

Answer 1

Don't worry about storing the ID, you need to go back and refactor to use the inbuilt identity stuff that's in the box for MVC. Looking at your code I can only assume that this system would store passwords in plain text. You will not pass any compliance with a system like this.
Rule of thumb when it comes to "is this secure" is don't write it yourself. Find a proven product and use that.
If for whatever reason the inbuilt identity system that is provided with MVC doesn't work for your requirements, have a look into this: https://github.com/brockallen/BrockAllen.MembershipReboot
FYI:
Identity system is the service that logs people in, out and manages the logged in user. Feel free to head over to this to learn more about the inbuilt system for MVC: http://www.asp.net/identity/overview/getting-started/introduction-to-aspnet-identity

Answer 2

For security concerns, would it be fine to store something like id's on cache? or it's better if i use sessions ?
In this case it doesn't make a lot of difference. However, the cache cannot be distributed across multiple web servers. Session state can by changing the <sessionState> section of the web.config file. So you are building an inherent limitation in scalability into your application by using cache.
Let's say i successfully logged in, and i add another line of this code :
HttpRuntime.Cache.Insert("id", id);
Is it going to edit my previous record or it's going to add another entry? I have this code from my Custom RoleProvider, HttpRuntime.Cache.Insert(cacheKey, roles, null, DateTime.Now.AddMinutes(_cacheTimeoutInMinute), Cache.NoSlidingExpiration); and i believe that they are "fired" everytime i ask a controller with a protection of [Authorize(Role="users")]. So does it make a new entry or it edits the previous/existing one?
First of all, you have a major flaw in your code. Cache is intended to be shared between all users on the site. So, when you insert a value, such as HttpRuntime.Cache.Insert("id", id);, all of the users will see it. If you are using this value to lookup data later, then the user data will always be for the last user that signed in.
You can fix this by adding adding a value unique to the user to the key.
var key = this.User.Identity.Name + "|Id";
HttpRuntime.Cache.Insert(key, id);
Note I am using a pipe character as a separator here. This is assuming the user name doesn't allow a pipe character (which you would also need to ensure).
Secondly, using a proper cache pattern means that you will never need to worry about whether "id" exists because you have already made that check. Using the cache typically looks like this.
public static string GetUserID()
{
// Check whether the user is logged in
if (!HttpContext.Current.User.Identity.IsAuthenticated) {
return 0;
}
// Make a UNIQUE key that can be used for this scenario
var userName = HttpContext.Current.User.Identity.Name;
var key = userName + "|Id";
// Attempt to get the ID from the cache
var id = HttpRuntime.Cache[key];
// A null value indicates there was no value in the cache
if (id == null)
{
// No ID in the cache, look it up from the database
using (EmployeeContext emp = new EmployeeContext())
{
id = (from user in emp.login
where user.username = userName
select user.id).First();
}
// Store the ID from the database into the cache
HttpRuntime.Cache.Insert(key, id,
// No Dependencies
null,
// No absolute expiration (mimic the behavior of forms authentication)
System.Web.Caching.Cache.NoAbsoluteExpiration,
// Timeout 20 minutes after the last access
// (to mimic the behavior of forms authentication)
new TimeSpan(0, 20, 0),
// Setting to NotRemovable ensures that if the
// application pool restarts, you don't lose your cache
System.Web.Caching.CacheItemPriority.NotRemovable,
// No callback needed here
null);
}
return (string)id
}
Of course, you can improve performance if the value is available at login by inserting it into the cache directly, but you need to ensure you use the same key in that case.
Session is probably a better choice in this scenario, but either way you should make use of this pattern to double check you have a value before returning it to the user.
Should i worry about deleting/clearing my cache as soon as the user decided to log out? my role provider timeout is currently set to 20 minutes
If you use Session state instead of cache this is much easier. Simply call Session.Abandon() when the user logs out.