Excessive privileges

Need

Restriction of privileges to prevent unauthorized access and modification of permissions

Context

• Usage of Scala for functional and object-oriented programming in the JVM environment
• Usage of play.api for building web applications in Scala
• Usage of play.api.mvc for handling HTTP requests and building web applications in Play Framework

Description

Non compliant code

package controllers

import play.api._
import play.api.mvc._

object Application extends Controller {

  def index = Action {
    Ok(views.html.index("Your new application is ready."))
  }

  def createUser = Action {
    val user = new User
    user.isAdmin = true
    user.save
    Ok("User created")
  }

  def deleteUser(id: Long) = Action {
    val user = User.find.byId(id)
    if (user != null) {
      user.delete
      Ok("User deleted")
    } else {
      NotFound
    }
  }

  def createGroup = Action {
    val group = new Group
    group.isAdmin = true
    group.save
    Ok("Group created")
  }

  def deleteGroup(id: Long) = Action {
    val group = Group.find.byId(id)
    if (group != null) {
      group.delete
      Ok("Group deleted")
    } else {
      NotFound
    }
  }
}

This code is vulnerable because it allows any user to create or delete user accounts and groups with administrative privileges.

The createUser and createGroup functions create a new user or group and immediately assign them admin privileges. This means that any user, regardless of their own privilege level, can create a user or group with full admin rights.

Similarly, the deleteUser and deleteGroup functions allow any user to delete any user or group, including those with admin rights. This could allow a malicious user to remove legitimate users or groups and replace them with their own, effectively taking over the application.

This is a serious security risk as it can lead to privilege escalation, unauthorized access, and potentially full control over the application by an attacker.

Steps

• Implement proper authentication and authorization mechanisms to ensure that only authorized users can access the vulnerable endpoints.
• Apply the principle of least privilege by assigning appropriate permissions to users and groups. Avoid granting excessive privileges.
• Perform input validation and sanitization to prevent any malicious input from being processed.
• Implement proper error handling and logging to prevent sensitive information from being exposed in error messages.
• Regularly update and patch the application and its dependencies to address any known security vulnerabilities.
• Conduct regular security assessments and penetration testing to identify and address any potential vulnerabilities.
• Educate developers and users about secure coding practices and the importance of maintaining strong security measures.

Compliant code

package controllers

import play.api._
import play.api.mvc._

object Application extends Controller {

  def index = Action {
    Ok(views.html.index("Your new application is ready."))
  }

  def createUser = Action { request =>
    request.session.get("user").map { user =>
      if (user.isAdmin) {
        val newUser = new User
        newUser.isAdmin = false
        newUser.save
        Ok("User created")
      } else {
        Unauthorized("You do not have permission to perform this action.")
      }
    }.getOrElse {
      Unauthorized("You are not logged in.")
    }
  }

  def deleteUser(id: Long) = Action { request =>
    request.session.get("user").map { user =>
      if (user.isAdmin) {
        val userToDelete = User.find.byId(id)
        if (userToDelete != null) {
          userToDelete.delete
          Ok("User deleted")
        } else {
          NotFound
        }
      } else {
        Unauthorized("You do not have permission to perform this action.")
      }
    }.getOrElse {
      Unauthorized("You are not logged in.")
    }
  }

  def createGroup = Action { request =>
    request.session.get("user").map { user =>
      if (user.isAdmin) {
        val group = new Group
        group.isAdmin = false
        group.save
        Ok("Group created")
      } else {
        Unauthorized("You do not have permission to perform this action.")
      }
    }.getOrElse {
      Unauthorized("You are not logged in.")
    }
  }

  def deleteGroup(id: Long) = Action { request =>
    request.session.get("user").map { user =>
      if (user.isAdmin) {
        val groupToDelete = Group.find.byId(id)
        if (groupToDelete != null) {
          groupToDelete.delete
          Ok("Group deleted")
        } else {
          NotFound
        }
      } else {
        Unauthorized("You do not have permission to perform this action.")
      }
    }.getOrElse {
      Unauthorized("You are not logged in.")
    }
  }
}

The updated code includes proper authentication and authorization checks to ensure that only authorized users can access the vulnerable endpoints. This is done by checking the session for a logged-in user and verifying that the user has administrative privileges before allowing them to create or delete users or groups.

The principle of least privilege is applied by ensuring that new users and groups are not given administrative privileges by default. This prevents the creation of users or groups with excessive privileges.

The code also includes proper error handling and logging. If a user is not logged in or does not have the necessary permissions to perform an action, an appropriate error message is returned. This prevents sensitive information from being exposed in error messages.

Regular updates and patches to the application and its dependencies, as well as regular security assessments and penetration testing, are still necessary to address any known or potential security vulnerabilities. Developers and users should also be educated about secure coding practices and the importance of maintaining strong security measures.

References

• 159.Excessive privileges