CSHARP.IO.INJ.XSS : Cross Site Scripting (C#)

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CodeSonar^® 9.2p0

CONFIDENTIAL

CodeSecure Inc

CSHARP.IO.INJ.XSS : Cross Site Scripting (C#)

Summary

Tainted data flows into a field annotated as [CrossSiteTrusted], or into a script execution routine.

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:

Properties

Examples

Example 1

using com.juliasoft.julia.checkers.injection;
using System;

using System.IO;
using System.Web;
using System.Web.UI;


namespace DocumentationExamples
{

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

        [SqlTrusted]
        private object sqlTrusted;
        [Trusted]
        private object trusted;
        public string a = "my friend";
        protected void Page_Load(object sender, EventArgs e)
        {
            ProcessRequest(Request, Response);
        }
        private void Test2([SqlTrusted] string s) { }
        private void Test3([Trusted] string s) { }
        private void ProcessRequest(HttpRequest request, HttpResponse response)
        {
            response.ContentType = "text/html;charset=UTF-8";
            string user = request.Params["user"];
            using (TextWriter p = response.Output)
            {
                p.WriteLine("User : " + user);  // Cross Site Scripting (C#) warning issued here
                p.WriteLine(user);              // Cross Site Scripting (C#) warning issued here
                p.WriteLine("hello");
                p.WriteLine("hello " + a);
            }
            if (user != null)
                Test2(user);                    // SQL Injection (C#) warning issued here 
            Test2("User: " + user);             //[SQL Injection (C#) warning issued here 
            Test2("hello");
            Test2("hello " + a);
            Test3(user);                        // Tainted @Trusted Value (C#) warning issued here 
            Test3("User: " + user);             // Tainted @Trusted Value (C#) warning issued here 
            Test3("hello");
            Test3("hello " + a);
            sqlTrusted = user;                  // SQL Injection (C#) warning issued here 
            trusted = user;                     // Tainted @Trusted Value (C#) warning issued here 
            sqlTrusted = "User: " + user;       // SQL Injection (C#) warning issued here 
            trusted = "User: " + user;          // Tainted @Trusted Value (C#) warning issued here 
            sqlTrusted = "hello";
            trusted = "hello";
            sqlTrusted = "hello " + a;
            trusted = "hello " + a;
        }
    }
}

Example 2

using com.juliasoft.julia.checkers.flows;
using com.juliasoft.julia.checkers.injection;
using System;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Web;
using System.Web.UI;

namespace DocumentationExamples
{

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

        [SqlTrusted]
        private object sqlTrusted;
        [Trusted]
        private object trusted;

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

        public void Test1([UntrustedUserInput] string user)
        {
            SqlConnection sqlConnection1 = new SqlConnection("Your Connection String");
            SqlCommand cmd = new SqlCommand();
            SqlDataReader reader;

            string query = "SELECT * FROM  User where userId='" + user + "'";


            cmd.CommandText = query;             // SQL Injection (C#) warning issued here
            cmd.CommandType = CommandType.Text;
            cmd.Connection = sqlConnection1;

            sqlConnection1.Open();

            reader = cmd.ExecuteReader();
            Console.WriteLine(cmd.CommandText);

            // the analyzer does not like these
            Test2(query + " extra characters");  // SQL Injection (C#) warning issued here 
            Test3(query + " hello");             // Tainted @Trusted Value (C#) warning issued here

            // while the analyzer likes this!
            Test2("driver".Substring(3, 5));

            sqlConnection1.Close();
        }

        private void Test2([SqlTrusted] string s) { }

        private void Test3([Trusted] string s) { }

        private void ProcessRequest(HttpRequest request, HttpResponse response)
        {
            response.ContentType = "text/html;charset=UTF-8";

            string user = request.Params["user"];

            using (SqlConnection conn = new SqlConnection("Connection String"))
            using (TextWriter p = response.Output)
            {
                SqlCommand st = conn.CreateCommand();
                string query = "SELECT * FROM  User where userId='" + user + "'";
                p.WriteLine(query);              // Cross Site Scripting (C#) warning issued here
                st.CommandText = query;          // SQL Injection (C#) warning issued here
                st.CommandType = CommandType.Text;
                SqlDataReader reader = st.ExecuteReader();
                trusted = query.Substring(5, 7); // Tainted @Trusted Value (C#) warning issued here
                sqlTrusted = query;              // SQL Injection (C#) warning issued here

                p.WriteLine("Results");
                while (reader.NextResult())
                {
                    string s = reader["address"] as string;
                    p.WriteLine("\t\t" + s);     // 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.