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Insecure authentication method - Basic

Need​

Secure authentication method

Context​

  • Usage of Scala for building scalable and high-performance applications
  • Usage of play.api.mvc for handling HTTP requests and responses in Play Framework

Description​

Non compliant code​

import play.api.mvc._

object Application extends Controller {
  
  def authenticate = Action { request =>
    request.headers.get("Authorization") match {
      case Some(BasicAuthentication(user, password)) => {
        // authenticate user
      }
      case _ => Unauthorized("Unauthorized")
    }
  }
  
  object BasicAuthentication {
    def unapply(header: String): Option[(String, String)] = {
      val (user, password) = decodeBasicAuth(header)
      Some(user, password)
    }
    
    private def decodeBasicAuth(auth: String): (String, String) = {
      val baStr = auth.stripPrefix("Basic ").trim
      val Array(user, password) = new String(java.util.Base64.getDecoder.decode(baStr), "UTF-8").split(":")
      (user, password)
    }
  }

}

The above code is a controller in a Scala application using the Play framework. The controller has an authenticate endpoint which uses Basic authentication over an insecure channel.

The authenticate method checks if the Authorization header is present in the request. If it is, it uses the BasicAuthentication object to decode the header and extract the username and password.

The BasicAuthentication object has an unapply method that is used to extract the username and password from the Authorization header. The decodeBasicAuth method removes the "Basic" prefix from the header, decodes the Base64 encoded string, and splits it into the username and password.

This code is vulnerable because it transmits the username and password over an insecure channel. An attacker could intercept the request and extract the username and password, leading to unauthorized access to the system.

Steps​

  • Use a secure channel (HTTPS) to transmit sensitive data, including authentication credentials.
  • Implement a stronger authentication method, such as token-based authentication or OAuth, instead of Basic authentication.
  • Ensure that the authentication method used is resistant to common attacks, such as brute force attacks or session hijacking.
  • Consider implementing additional security measures, such as rate limiting or multi-factor authentication, to enhance the overall security of the authentication process.

Compliant code​

import play.api.mvc._
import play.api.libs.ws._
import play.api.libs.oauth._

object Application extends Controller {
  
  val KEY = ConsumerKey("key", "secret")
  val oauth = OAuth(KEY, callbackURL = "http://localhost:9000/authenticate")
  
  def authenticate = Action.async { request =>
    request.getQueryString("oauth_verifier") match {
      case Some(verifier) => {
        val tokenPair = sessionTokenPair(request).get
        oauth.retrieveAccessToken(tokenPair, verifier) match {
          case Right(t) => {
            // authenticate user
            Future.successful(Ok("User authenticated"))
          }
          case _ => Future.successful(Unauthorized("Unauthorized"))
        }
      }
      case _ => Future.successful(Unauthorized("Unauthorized"))
    }
  }
  
  private def sessionTokenPair(implicit request: RequestHeader): Option[RequestToken] = {
    for {
      token <- request.session.get("token")
      secret <- request.session.get("secret")
    } yield {
      RequestToken(token, secret)
    }
  }

}

The updated code now uses OAuth for authentication instead of Basic authentication. OAuth is a more secure method of authentication as it allows users to approve the interaction between the server and the client without sharing their password.

The KEY is a ConsumerKey object that contains the key and secret provided by the OAuth provider. The oauth object is an instance of the OAuth class, which is used to handle the OAuth authentication process.

The authenticate method is now asynchronous and returns a Future[Result]. It retrieves the OAuth verifier from the request query string. If the verifier is present, it retrieves the access token using the retrieveAccessToken method of the oauth object. If the access token is successfully retrieved, the user is authenticated. If the access token retrieval fails, or if the verifier is not present in the request, the method returns an Unauthorized result.

The sessionTokenPair method retrieves the request token and secret from the session. These are used to retrieve the access token.

This code assumes that the server is running on http://localhost:9000 and that the callback URL for the OAuth provider is set to http://localhost:9000/authenticate. These values should be updated to match the actual server URL and OAuth provider callback URL.

This code also assumes that the OAuth provider has provided a key and secret. These values should be replaced with the actual key and secret provided by the OAuth provider.

This code does not include error handling for cases where the key, secret, or callback URL are not correctly configured. Additional error handling should be added as appropriate for the specific application and OAuth provider.

References​

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