CSHARP.IO.INJ.XSS.EMWP : Cross Site Scripting In Error Message Web Page (C#)

Summary

Tainted data flows into a field annotated as [CrossSiteTrusted] and [SendWebError], or into a script execution routine that send an web page error.

Checks for this class use the CodeSonar C# taint analysis. See Taint Tracking for CodeSonar C# Warning Classes for more information on this analysis, including lists of the methods that CodeSonar automatically recognizes as relevant and information about specifying additional methods that CodeSonar should recognize as taint sources, sinks, or sanitizers.

Use configuration parameter CSHARP_ANALYSIS_ADVANCED_INJECTION to specify the level of checking to perform for this and other taint-related warning classes:

• For basic checking, set CSHARP_ANALYSIS_ADVANCED_INJECTION=No in your project configuration file.
• For advanced checking, set CSHARP_ANALYSIS_ADVANCED_INJECTION=Yes.

Properties

WARNING_FILTER += discard class="Cross Site Scripting In Error Message Web Page (C#)"

Examples

using System;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Web;
using System.Web.UI;

namespace DocumentationExamples {

    public class InjectionTest : Page {
        public static void Main(string[] args) { }

        public void Page_Load(object source, EventArgs e) {
            ProcessRequest(Request, Response);
        }

        private void ProcessRequest(HttpRequest request, HttpResponse response) {
            response.ContentType = "text/html;charset=UTF-8";
            string data = request.Params["data"];
            // ...
            response.StatusCode = 404
            response.StatusDescription = data // 'Cross Site Scripting (C#)' warning issued here
            // ...
            }
        }
    }
}

Resolution

Verify that a security error actually corresponds to unconstrained information flow from source locations into sink locations. If this is the case, add a sanitizing algorithm to clean data before it flows into sinks, or use safe statements to propagate data inside the program.

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.

• CSHARP_ANALYSIS_ADVANCED_INJECTION
• REPORT_SIMILAR_WARNINGS
• WARNING_FILTER