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Insecure object reference - Corporate information

Need​

Secure handling of object references for corporate information

Context​

  • Usage of Scala 2.12.10 for building scalable and high-performance applications
  • Usage of play.api.mvc.Action for handling HTTP requests in Play Framework
  • Usage of play.api.mvc.MultipartFormData for handling multipart form data in Play Framework
  • Usage of play.api.mvc.Request for handling HTTP requests in Play Framework
  • Usage of play.api.mvc.Result for handling HTTP responses in Play Framework
  • Usage of play.api.mvc.Results for handling HTTP responses in Play Framework
  • Usage of play.api.mvc.AnyContent for handling any type of content in Play Framework
  • Usage of AnyContentAsMultipartFormData in Play Framework for handling multipart form data
  • Usage of play.api.mvc.MultipartFormData.FilePart for handling file uploads in Play Framework
  • Usage of TemporaryFile for handling temporary files in Play Framework
  • Usage of scala.collection.immutable.List for immutable list operations in Scala
  • Usage of java.io.File for file input/output operations

Description​

Non compliant code​

def uploadFile = Action(parse.multipartFormData) { request =>
  request.body.file("excel").map { excelFile =>
    val companyIdentifier = request.body.dataParts("payrollNumber").headOption
    val employees = parseExcelFile(excelFile)
    companyIdentifier.map { payrollNumber =>
      employees.foreach { employee =>
        EmployeeModel.updateOrCreate(payrollNumber, employee)
      }
      Ok("File has been uploaded and data processed.")
    }.getOrElse {
      BadRequest("Missing company identifier.")
    }
  }.getOrElse {
    BadRequest("Missing file.")
  }
}

def parseExcelFile(file: FilePart[TemporaryFile]): List[Employee] = {
  // Logic to parse the Excel file and return a list of Employee objects
}

object EmployeeModel {
  def updateOrCreate(payrollNumber: String, employee: Employee): Unit = {
    // Logic to update or create an Employee in the database
  }
}

The above code represents an insecure object reference vulnerability. The Play Framework action uploadFile is responsible for handling file uploads, specifically excel files that contain employee data.

The vulnerability arises from the fact that the company identifier (payroll number) is taken directly from the request data and used to update or create Employee records in the database. There is no check to ensure that the user making the request has the appropriate permissions to modify data for the company identified by the payroll number.

When the excel file is uploaded, it is parsed into a list of Employee objects. These Employee objects are then passed, along with the payroll number, to the updateOrCreate method of the EmployeeModel. This method updates existing records or creates new ones based on the data provided. However, because there is no access control check before this operation, an attacker could potentially modify employee data for any company just by knowing its payroll number.

This means an attacker could upload a crafted excel file and specify a payroll number for a company they do not have access to, resulting in unauthorized modification of that company's employee data.

Steps​

  • Implement proper authentication and authorization mechanisms to ensure that only authorized users can access and modify employee information.
  • Validate the company identifier (payrollNumber) to ensure that the user has permission to access and modify the corresponding company's data.
  • Implement server-side validation of the uploaded Excel file to ensure it contains valid and expected data.
  • Use a secure file upload mechanism that includes file type validation, size restrictions, and proper file handling to prevent malicious file uploads.
  • Implement input validation and sanitization to prevent any potential injection attacks.
  • Implement proper error handling and error messages to provide meaningful feedback to the user in case of any issues or failures during the file upload and data processing.
  • Consider implementing logging and monitoring mechanisms to track and detect any suspicious activities or unauthorized access attempts.
  • Regularly update and patch the underlying frameworks and libraries used in the application to address any known security vulnerabilities.

Compliant code​

import play.api.mvc.Security.AuthenticatedRequest

def uploadFile = Action(parse.multipartFormData) { implicit request =>
  request.body.file("excel").map { excelFile =>
    val companyIdentifier = request.body.dataParts("payrollNumber").headOption
    val employees = parseExcelFile(excelFile)
    companyIdentifier.map { payrollNumber =>
      if (isAuthorized(payrollNumber)) {
        employees.foreach { employee =>
          EmployeeModel.updateOrCreate(payrollNumber, employee)
        }
        Ok("File has been uploaded and data processed.")
      } else {
        Unauthorized("You are not authorized to modify this company's data.")
      }
    }.getOrElse {
      BadRequest("Missing company identifier.")
    }
  }.getOrElse {
    BadRequest("Missing file.")
  }
}

def isAuthorized(payrollNumber: String)(implicit request: AuthenticatedRequest[_, _]): Boolean = {
  // Logic to check if the user is authorized to modify the company's data
}

def parseExcelFile(file: FilePart[TemporaryFile]): List[Employee] = {
  // Logic to parse the Excel file and return a list of Employee objects
}

object EmployeeModel {
  def updateOrCreate(payrollNumber: String, employee: Employee): Unit = {
    // Logic to update or create an Employee in the database
  }
}

The updated code includes an authorization check to ensure that the user is authorized to modify the company's data. This is done by adding a new function isAuthorized that takes the payrollNumber as a parameter and checks if the user is authorized to modify the company's data. This function is called before updating or creating an Employee in the database.

The uploadFile function now includes a check for authorization. If the user is not authorized to modify the company's data, the function returns an Unauthorized response. If the user is authorized, the function proceeds as before.

The isAuthorized function uses the AuthenticatedRequest implicit parameter to get information about the authenticated user. This information can be used to check if the user has the necessary permissions to modify the company's data.

This solution ensures that only authorized users can modify the company's data, thus preventing unauthorized access and modification of data. It also provides meaningful feedback to the user in case of unauthorized access attempts.

References​

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