Need

Secure session management

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 {
    var sessionToken: String?

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        sessionToken = "1234567890"
    }

    func postRequest() {
        if let token = sessionToken {
            // post request using session token
            print("Post request using session token: \\(token)")
        }
    }

    func terminateSession() {
        // here, session token is not set to nil after termination of session
        print("Session terminated")
    }
}
        
        

In the above code snippet, a sessionToken is assigned when the ViewController is loaded. This token is used for posting requests in the postRequest function.

The vulnerability lies in the terminateSession function. When a user terminates a session, the sessionToken should be invalidated to prevent further requests from being made using the same token. However, in this code, the sessionToken is not set to nil when the session is terminated. This means that the token remains active after session termination and can be used to post requests afterwards, leading to insecure session management.

Steps

• Implement a session timeout mechanism to automatically expire the session after a certain period of inactivity.
• When the session is terminated, set the session token to nil or remove it from memory to ensure it cannot be used for subsequent requests.
• Consider using secure session management techniques such as using secure cookies or JSON Web Tokens (JWT) with expiration dates and signature verification.
• Implement strong authentication mechanisms to prevent unauthorized access to the session token.
• Regularly review and update the session management implementation to address any new vulnerabilities or best practices.

Compliant code

        import UIKit

class ViewController: UIViewController {
    var sessionToken: String?

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        sessionToken = "1234567890"
    }

    func postRequest() {
        if let token = sessionToken {
            // post request using session token
            print("Post request using session token: \\(token)")
        } else {
            print("Session token is not available. Please login again.")
        }
    }

    func terminateSession() {
        // Set session token to nil after termination of session
        sessionToken = nil
        print("Session terminated")
    }
}
        
        

The updated code now includes a mechanism to invalidate the session token once the session is terminated. This is done by setting the sessionToken to nil in the terminateSession() function. This ensures that the session token cannot be used for subsequent requests after the session has been terminated.

In the postRequest() function, we check if the sessionToken is nil before making a post request. If the sessionToken is nil, it means the session has been terminated or the user is not logged in, and we print a message asking the user to login again.

This is a simple fix for the insecure session management vulnerability. However, for a more secure session management, consider using secure session management techniques such as using secure cookies or JSON Web Tokens (JWT) with expiration dates and signature verification. Also, implement strong authentication mechanisms to prevent unauthorized access to the session token. Regularly review and update the session management implementation to address any new vulnerabilities or best practices.

References

• 076. Insecure session management