Struts網站基於Filter的XSS漏洞修復

下面的代碼只支持struts2框架中的xss漏洞

第一步,創建過濾器XssFilter :

package com.ulic.ulcif.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

import com.ulic.ulcif.requestwrapper.XssHttpServletRequestWrapper;

/**
 *  XSS防跨站腳本攻擊過濾器
 *
 */
public class XssFilter implements Filter {
     FilterConfig filterConfig = null;
     /**
         * Default constructor. 
         */
    public XssFilter() {
    }

    public void destroy() {
        this.filterConfig = null;  
    }
    
    public void init(FilterConfig fConfig) throws ServletException {
        this.filterConfig = fConfig; 
    }
    
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        chain.doFilter(new XssHttpServletRequestWrapper((HttpServletRequest) request), response);
    }


}

第二步,創建業務操作XssHttpServletRequestWrapper:

package com.ulic.ulcif.requestwrapper;

import java.util.Enumeration;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.dispatcher.StrutsRequestWrapper;
import org.springframework.util.CollectionUtils;

/**
 * 寫一個 Filter，使用 Filter 來過濾瀏覽器發出的請求。對每個 post 請求的參數過濾一些關鍵字，替換成安全的，例如：< > ' " \ / # & 。
 * 
 * 方法:實現一個自定義的 HttpServletRequestWrapper，然后在 Filter 里面調用它，替換掉 getParameter 函數即可
 */
public class XssHttpServletRequestWrapper extends StrutsRequestWrapper  {
    
    HttpServletRequest orgRequest = null; 
    
    public XssHttpServletRequestWrapper(HttpServletRequest servletRequest) {
        super(servletRequest);
        orgRequest = servletRequest;
    }
    
    /**
     * 重寫getParameterValues方法
     * 通過循環取出每一個請求結果
     * 再對請求結果進行過濾
     * */
    public String[] getParameterValues(String parameter) {
        String[] values = super.getParameterValues(parameter);
        if (values == null) {
            return null;
        }
        int count = values.length;
        String[] encodedValues = new String[count];
        for (int i = 0; i < count; i++) {
            encodedValues[i] = cleanXSS(values[i]);
        }
        return encodedValues;
    }
    
    /**
     * 重寫getParameter方法
     * 對請求結果進行過濾
     * */
    public String getParameter(String parameter) {
        String value = super.getParameter(parameter);
        if (value == null) {
            return null;
        }
        return cleanXSS(value);
    }
    
    public String getHeader(String name) {
        String value = super.getHeader(name);
        if (value == null)
            return null;
        return cleanXSS(value);
    }
     /** 
       * 獲取最原始的request 
       *  
       * @return 
       */  
      public HttpServletRequest getOrgRequest() {  
          return orgRequest;  
      }  

      /** 
       * 獲取最原始的request的靜態方法 
       *  
       * @return 
       */  
      public static HttpServletRequest getOrgRequest(HttpServletRequest req) {  
          if (req instanceof XssHttpServletRequestWrapper) {  
              return ((XssHttpServletRequestWrapper) req).getOrgRequest();  
          }  
          return req;  
      }
      
      @Override
        public Enumeration<String> getParameterNames() {
            Enumeration<String> names = super.getParameterNames();
            while(names.hasMoreElements()){
                String name = names.nextElement();
                name = cleanXSS(name);
            }
            return names;
        }
      
      
      @Override
      public Map getParameterMap() {
            
          Map paramMap = super.getParameterMap();
          if (CollectionUtils.isEmpty(paramMap)) {
              return paramMap;
          }
            
          for (Object value : paramMap.values()) { 
              String[] str = (String[])value;
              if (str != null) {
                  for (int i = 0; i < str.length; i++) {
                        
                      str[i] = cleanXSS(str[i]);
                  }
              }
          }
          return paramMap;
      }

    private String cleanXSS(String value) {
        value = value.replaceAll("<", "& lt;").replaceAll(">", "& gt;");
        //先暫時去除 英文括號的攔截
//        value = value.replaceAll("\\(", "& #40;").replaceAll("\\)", "& #41;");
        value = value.replaceAll("'", "& #39;");
        value = value.replaceAll("eval\\((.*)\\)", "");
        value = value.replaceAll("[\\\"\\\'][\\s]*javascript:(.*)[\\\"\\\']","\"\"");
        value = value.replaceAll("script", "");
        value = value.replaceAll("alert", "");
        
        return value;
    }
}

第三步在web.xml中配置:

<filter>
        <filter-name>struts-xssFilter</filter-name>
        <filter-class>
            com.ulic.ulcif.filter.XssFilter
        </filter-class>
    </filter>

<filter-mapping>
        <filter-name>struts-xssFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

到此為止xss在struts2中得到了解決,那么非struts2中xss漏洞怎么解決呢,簡單,將第二步換成:如下代碼

package com.ulic.ulcif.requestwrapper;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

/**
 * 寫一個 Filter，使用 Filter 來過濾瀏覽器發出的請求。對每個 post 請求的參數過濾一些關鍵字，替換成安全的，例如：< > ' " \ / # & 。
 * 
 * 方法:實現一個自定義的 HttpServletRequestWrapper，然后在 Filter 里面調用它，替換掉 getParameter 函數即可
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
    
    HttpServletRequest orgRequest = null; 
    
    public XssHttpServletRequestWrapper(HttpServletRequest servletRequest) {
        super(servletRequest);
        orgRequest = servletRequest;
    }
    
    /**
     * 重寫getParameterValues方法
     * 通過循環取出每一個請求結果
     * 再對請求結果進行過濾
     * */
    public String[] getParameterValues(String parameter) {
        String[] values = super.getParameterValues(parameter);
        if (values == null) {
            return null;
        }
        int count = values.length;
        String[] encodedValues = new String[count];
        for (int i = 0; i < count; i++) {
            encodedValues[i] = cleanXSS(values[i]);
        }
        return encodedValues;
    }
    
    /**
     * 重寫getParameter方法
     * 對請求結果進行過濾
     * */
    public String getParameter(String parameter) {
        String value = super.getParameter(parameter);
        if (value == null) {
            return null;
        }
        return cleanXSS(value);
    }
    
    public String getHeader(String name) {
        String value = super.getHeader(name);
        if (value == null)
            return null;
        return cleanXSS(value);
    }
      
    private String cleanXSS(String value) {
        value = value.replaceAll("<", "& lt;").replaceAll(">", "& gt;");
        //先暫時去除 英文括號的攔截
//        value = value.replaceAll("\\(", "& #40;").replaceAll("\\)", "& #41;");
        value = value.replaceAll("'", "& #39;");
        value = value.replaceAll("eval\\((.*)\\)", "");
        value = value.replaceAll("[\\\"\\\'][\\s]*javascript:(.*)[\\\"\\\']","\"\"");
        value = value.replaceAll("script", "");
        value = value.replaceAll("alert", "");
        
        return value;
    }
}