XssChallengeFour.java

package servlets.module.challenge;

import dbProcs.Getter;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Locale;
import java.util.ResourceBundle;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import utils.FindXSS;
import utils.Hash;
import utils.ShepherdLogManager;
import utils.Validate;
import utils.XssFilter;

/**
 * Cross Site Scripting Challenge Four control class. <br>
 * <br>
 * This file is part of the Security Shepherd Project.
 *
 * <p>The Security Shepherd project is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.<br>
 *
 * <p>The Security Shepherd project is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE. See the GNU General Public License for more details.<br>
 *
 * <p>You should have received a copy of the GNU General Public License along with the Security
 * Shepherd project. If not, see <http://www.gnu.org/licenses/>.
 *
 * @author Mark Denihan
 */
public class XssChallengeFour extends HttpServlet {

  private static final long serialVersionUID = 1L;
  private static final Logger log = LogManager.getLogger(XssChallengeFour.class);
  private static final String levelHash =
      "06f81ca93f26236112f8e31f32939bd496ffe8c9f7b564bce32bd5e3a8c2f751";
  private static String levelName = "XSS Challenge 4";

  /**
   * Cross Site Request Forgery safe Reflected XSS vulnerability. cannot be remotely exploited, and
   * there fore only is executable against the person initiating the function.
   *
   * @param searchTerm To be spat back out at the user after been encoded for wrong HTML Context
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    // Setting IpAddress To Log and taking header for original IP if forwarded from proxy
    ShepherdLogManager.setRequestIp(request.getRemoteAddr(), request.getHeader("X-Forwarded-For"));
    log.debug("Cross-Site Scripting Challenge Four Servlet");
    PrintWriter out = response.getWriter();
    out.print(getServletInfo());

    // Translation Stuff
    Locale locale = new Locale(Validate.validateLanguage(request.getSession()));
    ResourceBundle errors = ResourceBundle.getBundle("i18n.servlets.errors", locale);
    ResourceBundle bundle = ResourceBundle.getBundle("i18n.servlets.challenges.xss.xss4", locale);

    try {
      HttpSession ses = request.getSession(true);
      if (Validate.validateSession(ses)) {
        ShepherdLogManager.setRequestIp(
            request.getRemoteAddr(),
            request.getHeader("X-Forwarded-For"),
            ses.getAttribute("userName").toString());
        log.debug(levelName + " servlet accessed by: " + ses.getAttribute("userName").toString());
        Cookie tokenCookie = Validate.getToken(request.getCookies());
        Object tokenParmeter = request.getParameter("csrfToken");
        if (Validate.validateTokens(tokenCookie, tokenParmeter)) {
          String htmlOutput = new String();
          String userPost = new String();
          String searchTerm = request.getParameter("searchTerm");
          log.debug("User Submitted - " + searchTerm);
          if (!searchTerm.startsWith("http")) {
            searchTerm = "https://www.owasp.org/index.php/OWASP_Security_Shepherd";
            userPost =
                "<a href=\""
                    + searchTerm
                    + "\" alt=\"OWASP Security Shepherd\">"
                    + searchTerm
                    + "</a>";
          } else {

            searchTerm = XssFilter.encodeForHtml(searchTerm);
            userPost =
                "<a href=\"" + searchTerm + "\" alt=\"" + searchTerm + "\">" + searchTerm + "</a>";
            log.debug("After Encoding - " + searchTerm);
            if (FindXSS.search(userPost)) {
              htmlOutput =
                  "<h2 class='title'>"
                      + bundle.getString("result.wellDone")
                      + "</h2>"
                      + "<p>"
                      + bundle.getString("result.youDidIt")
                      + "<br />"
                      + bundle.getString("result.resultKey")
                      + " <a>"
                      + Hash.generateUserSolution(
                          Getter.getModuleResultFromHash(
                              getServletContext().getRealPath(""), levelHash),
                          (String) ses.getAttribute("userName"))
                      + "</a>";
            }
          }
          log.debug("Adding searchTerm to Html: " + searchTerm);
          htmlOutput +=
              "<h2 class='title'>"
                  + bundle.getString("response.yourPost")
                  + "</h2>"
                  + "<p>"
                  + bundle.getString("response.linkPosted")
                  + "</p> "
                  + userPost
                  + "</p>";
          out.write(htmlOutput);
        }
      } else {
        log.error(levelName + " servlet was accessed without a valid session");
        out.write(errors.getString("error.noSession"));
      }
    } catch (Exception e) {
      out.write(errors.getString("error.funky"));
      log.fatal("Cross Site Scripting Challenge 4 - " + e.toString());
    }
  }
}