JAVA.IO.INJ.XSS : Cross Site Scripting (Java)

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CodeSonar^® 9.2p0

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CodeSecure Inc

JAVA.IO.INJ.XSS : Cross Site Scripting (Java)

Summary

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

Checks for this class use the CodeSonar Java taint analysis. See Taint Tracking for CodeSonar Java 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 JAVA_ANALYSIS_ADVANCED_INJECTION to specify the level of checking to perform for this and other taint-related warning classes:

Properties

Example

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.juliasoft.julia.checkers.injection.SqlTrusted;
import com.juliasoft.julia.checkers.injection.Trusted;

@SuppressWarnings("serial")
public class BasicInjection extends HttpServlet {
  private @SqlTrusted Object sqlTrusted;
  private @Trusted Object trusted;
  public String a = "my friend";

  @Override
  protected final void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
    processRequest(request, response);
  }

  private void test2(@SqlTrusted String s) {}

  private void test3(@Trusted String s) {}

  private void processRequest(HttpServletRequest request, HttpServletResponse response) throws IOException {
    response.setContentType("text/html;charset=UTF-8");

    String user = request.getParameter("user");              // The value of variable 'user' is obtained from user input
      out.println(user);                                     // and is therefore treated as tainted.

    try (PrintWriter out = response.getWriter()) {
      out.println("User : " + user); // Cross Site Scripting (Java) warning issued here
      out.println(user);             // Cross Site Scripting (Java) warning issued here
      out.println("hello");
      out.println("hello " + a);
    }

    if (user != null)
      test2(user);                   // SQL Injection (Java) warning issued here
    test2("User: " + user);          // SQL Injection (Java) warning issued here
    test2("hello");
    test2("hello " + a);
    test3(user);                     // Tainted @Trusted Value (Java) warning issued here
    test3("User: " + user);          // Tainted @Trusted Value (Java) warning issued here
    test3("hello");
    test3("hello " + a);
    sqlTrusted = user;               // SQL Injection (Java) warning issued here
    trusted = user;                  // Tainted @Trusted Value (Java) warning issued here
    sqlTrusted = "User: " + user;    // SQL Injection (Java) warning issued here
    trusted = "User: " + user;       // Tainted @Trusted Value (Java) warning issued here
    sqlTrusted = "hello";
    trusted = "hello";
    sqlTrusted = "hello " + a;
    trusted = "hello " + a;
  }
}

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.juliasoft.julia.checkers.flows.UntrustedUserInput;
import com.juliasoft.julia.checkers.injection.SqlTrusted;
import com.juliasoft.julia.checkers.injection.Trusted;
import com.juliasoft.julia.extraction.EntryPoint;

public class SqlInjection extends HttpServlet {
  private @SqlTrusted Object sqlTrusted;
  private @Trusted Object trusted;

  @Override
  protected final void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
      processRequest(request, response);
  }

  @Override
  protected final void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
      processRequest(request, response);
  }

  public @EntryPoint void test1(@UntrustedUserInput String user) {
      Connection conn = null;
      String url = "jdbc:mysql://192.168.2.128:3306/";
      String dbName = "anvayaV2";
      String driver = "com.mysql.jdbc.Driver";
      String userName = "root";
      String password = "";
      // with the following assignment, there is no injection anymore at line 48
      // user = "erasmus";

      try {
        Class.forName(driver).newInstance();
        conn = DriverManager.getConnection(url + dbName, userName, password);

        Statement st = conn.createStatement();
        String query = "SELECT * FROM  User where userId='" + user + "'";
        System.out.printf(query);
        st.executeQuery(query);                 // SQL Injection (Java) warning issued here

        test2(query + " extra characters");     /* SQL Injection (Java) warning issued here
                                                 * only if JAVA_ANALYSIS_ADVANCED_INJECTION=Yes 
                                                 */ 
        test3(query + " hello");                /* Tainted @Trusted Value (Java) warning issued here
                                                 * only if JAVA_ANALYSIS_ADVANCED_INJECTION=Yes 
                                                 */ 

        test2("driver".substring(3, 5));

        conn.close();
      } catch (Exception e) {
        e.printStackTrace();
      }
  }

  private void test2(@SqlTrusted String s) {
  }

  private void test3(@Trusted String s) {
  }

  private void processRequest(HttpServletRequest request, HttpServletResponse response) throws IOException {
      response.setContentType("text/html;charset=UTF-8");

      String user = request.getParameter("user");
      String url = "jdbc:mysql://192.168.2.128:3306/";
      String dbName = "anvayaV2";
      String driver = "com.mysql.jdbc.Driver";
      String userName = "root";
      String password = "";

      try {
        Class.forName(driver).newInstance();
      }
      catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
        return;
      }

      try (Connection conn = DriverManager.getConnection(url + dbName, userName, password);
           PrintWriter out = response.getWriter())  {
        Statement st = conn.createStatement();
        String query = "SELECT * FROM  User where userId='" + user + "'";
        out.println("Query : " + query);        // Cross-Site Scripting (Java) warning issued here
        System.out.printf(query);
        ResultSet res = st.executeQuery(query); // SQL Injection (Java) warning issued here
        trusted = query.substring(5, 7);        // Tainted @Trusted Value (Java) warning issued here
        sqlTrusted = query;                     // SQL Injection (Java) warning issued here

        out.println("Results");
        while (res.next()) {
            String s = res.getString("address");
            out.println("\t\t" + s);            // Cross-Site Scripting (Java) warning issued here
        }
      }
      catch (SQLException e) {}
    }
}

In this example, the programmer should avoid a direct flow of user input into database queries or into the output stream of the servlet. The solution is to use a sanitizing method that guarantees the correct handling of user input, so that it becomes harmless (see the list of Java methods recognized by CodeSonar), or to use prepared statements for database queries, or to implement proprietary sanitizing methods. For an example of the last case, the query might be passed through a sanitizing method such as query = clean(query) just after the construction of the query string.

private @Trusted String clean(String query) {
  return ...sanitized query
}

The @Trusted annotation is needed here to inform the analyzer the fact that this is a sanitizing method, whose result is always trusted.

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.