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Lack of data validation - HTML code

Description​

Es posible inyectar código HTML válido, que podría interpretarse en el sitio que reciba el JSON de respuesta.

Impact​

  • Insert character sequences whose semantics result in the creation of new HTML elements, log file injection, remote command execution or insecure file fetching.
  • Create delivery requests for non-existent QR codes, since the idQR field accepts text strings with random characters.

Recommendation​

Validate on the server side the types of data that are entered into different types of fields in the application.

Threat​

Unauthorized attacker on the Internet.

Expected Remediation Time​

⌚ 90 minutes.

Score​

Default score using CVSS 3.1. It may change depending on the context of the vulnerability.

Base​

  • Attack vector: N
  • Attack complexity: L
  • Privileges required: N
  • User interaction: N
  • Scope: U
  • Confidentiality: N
  • Integrity: L
  • Availability: N

Temporal​

  • Exploit code madurity: X
  • Remediation level: X
  • Report confidence: X

Result​

  • Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:X/RL:X/RC:X
  • Score:
    • Base: 5.3
    • Temporal: 5.3
  • Severity:
    • Base: Medium
    • Temporal: Medium

Code Examples​

Compliant code​

All input data correctly validates input data before using it

public void doPost( HttpServletRequest request, HttpServletResponse response){
  try {
    String qrRequest = request.getParameter( "idQR" );
    //Use a method to validate that the request is valid using whitelists or similar secure methods
    if ( isValidQR(qrRequest) ) {
      throw new YourValidationException( "Improper file" );
    }
    // Process after its been validated ..
  } catch(YourValidationException e ) {
    response.sendError( response.SC_BAD_REQUEST, e.getMessage() );
  }
}

Non compliant code​

There is unvalidated input data handled by the application

public void doPost( HttpServletRequest request, HttpServletResponse response){
  try {
    String qrRequest = request.getParameter( "idQR" );
    // Process qr code without validating
  } catch(YourValidationException e ) {
    response.sendError( response.SC_BAD_REQUEST, e.getMessage() );
  }
}

Requirements​