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Lack of data validation

Need​

Implementation of robust data validation mechanisms

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
  • Usage of javax.inject.Inject for dependency injection in Java applications
  • Usage of play.api.mvc.ControllerComponents for handling HTTP requests in Play Framework
  • Usage of AbstractController in the play.api.mvc package for creating controllers in the Play framework
  • Usage of play.api.mvc.Action for handling HTTP requests in Play Framework
  • Usage of play.api.db.Database for database operations in Play Framework

Description​

Non compliant code​

import play.api.mvc._

class ApplicationController @Inject()(cc: ControllerComponents) extends AbstractController(cc) {

  def updateRecord = Action { request =>
    val id = request.body.asFormUrlEncoded.get("id").head
    val name = request.body.asFormUrlEncoded.get("name").head
    val email = request.body.asFormUrlEncoded.get("email").head

    // update the record in the database
    Database.update(id, name, email)
    Ok("Record updated")
  }
}

In the above code, the updateRecord function accepts a POST request and directly uses the data from the request body to update a record in the database.

The id, name, and email fields are extracted from the request body without any validation. This means that the server is trusting that the client will always send valid data. However, an attacker could send an invalid id (such as an id composed of only letters), which could potentially cause unexpected behavior or errors in the application.

This lack of data validation is a significant security vulnerability. It opens the application up to various attacks, such as SQL Injection, Cross-Site Scripting (XSS), and can potentially lead to data corruption or loss.

Steps​

  • Implement server-side data validation to ensure that the received data is valid.
  • Validate the 'id' field to ensure it meets the required format (e.g., alphanumeric characters only).
  • Validate the 'name' field to ensure it is not empty and does not contain any invalid characters.
  • Validate the 'email' field to ensure it is a valid email address.
  • Handle validation errors appropriately and provide meaningful error messages to the user.
  • Consider using a validation library or framework to simplify the validation process.

Compliant code​

import play.api.data._
import play.api.data.Forms._
import play.api.mvc._

class ApplicationController @Inject()(cc: ControllerComponents) extends AbstractController(cc) {

  val userForm: Form[UserData] = Form(
    mapping(
      "id" -> nonEmptyText.verifying("Invalid ID", id => id.matches("[a-zA-Z0-9]*")),
      "name" -> nonEmptyText.verifying("Invalid name", name => name.matches("[a-zA-Z]*")),
      "email" -> email
    )(UserData.apply)(UserData.unapply)
  )

  def updateRecord = Action { implicit request =>
    userForm.bindFromRequest.fold(
      formWithErrors => {
        // binding failure, you retrieve the form containing errors:
        BadRequest("Invalid data")
      },
      userData => {
        /* binding success, you get the actual value. */
        Database.update(userData.id, userData.name, userData.email)
        Ok("Record updated")
      }
    )
  }
}

case class UserData(id: String, name: String, email: String)

The updated code now includes server-side data validation for the 'id', 'name', and 'email' fields.

The userForm is a Form object that maps the request data to a UserData case class. It uses the mapping method to define the validation rules for each field:

  • The 'id' field must be a non-empty string that only contains alphanumeric characters. This is enforced by the nonEmptyText method and the verifying method with a regular expression that matches any string composed of zero or more alphanumeric characters.
  • The 'name' field must be a non-empty string that only contains alphabetic characters. This is enforced by the nonEmptyText method and the verifying method with a regular expression that matches any string composed of zero or more alphabetic characters.
  • The 'email' field must be a valid email address. This is enforced by the email method.

The updateRecord method now uses the bindFromRequest method to bind the request data to the userForm. If the binding is successful, it updates the record in the database with the validated data. If the binding fails, it returns a "Bad Request" response with an error message.

This approach ensures that only valid data is used to update the record in the database, which helps to prevent various types of attacks and errors.

References​

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