Java Web XSS安全防御

以你之姓@ 2022-04-06 03:38 260阅读 0赞

XSS攻击简单来讲就是攻击者在请求中巧妙地加上执行脚本，达到攻击的目的。实践过滤器方案和JSP的EL表达式+JSTL标签库方案都还可以达到防XSS攻击的目的。

**一.过滤器方案**

XSSFilter.java

package com.bijian.study.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.annotation.WebFilter;
    import javax.servlet.http.HttpServletRequest;
    
    /**
     * Servlet Filter implementation class XSSFilter
     */
    @WebFilter("/XSSFilter")
    public class XSSFilter implements Filter {
        
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
        }
    
        @Override
        public void destroy() {
        }
    
        @Override
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
                ServletException {
    
            chain.doFilter(new XSSRequestWrapper((HttpServletRequest) request), response);
        }
    }

XSSRequestWrapper.java

package com.bijian.study.filter;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletRequestWrapper;
    
    import org.apache.commons.lang.StringEscapeUtils;
    
    public class XSSRequestWrapper extends HttpServletRequestWrapper {
        
        public XSSRequestWrapper(HttpServletRequest servletRequest) {
            super(servletRequest);
        }
    
        @Override
        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] = stripXSS(values[i]);
            }
            return encodedValues;
        }
    
        @Override
        public String getParameter(String parameter) {
            String value = super.getParameter(parameter);
            return stripXSS(value);
        }
    
        @Override
        public String getHeader(String name) {
            String value = super.getHeader(name);
            return stripXSS(value);
        }
    
        private String stripXSS(String value) {
            value = StringEscapeUtils.escapeHtml(value); 
            value = StringEscapeUtils.escapeJavaScript(value); 
            value = StringEscapeUtils.escapeSql(value);
            return value;
        }
    }

web.xml中的配置

<filter>
    	<filter-name>XSSFilter</filter-name>
    	<filter-class>com.bijian.study.filter.XSSFilter</filter-class>
    </filter>
    <filter-mapping>
    	<filter-name>XSSFilter</filter-name>
    	<url-pattern>*.do</url-pattern>
    </filter-mapping>
    <filter-mapping>
    	<filter-name>XSSFilter</filter-name>
    	<url-pattern>*.jsp</url-pattern>
    </filter-mapping>

**二.JSP的EL表达式+JSTL标签库方案**

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
    <%
    	String path = request.getContextPath();
    	String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";
    	String nameStr = request.getParameter("name");//用request得到
    	request.setAttribute("nameAttr", nameStr);
    %> 
    <!DOCTYPE html>   
    <html>   
    <head>   
    	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">   
    	<title>Hello</title>   
    </head>   
    <body>
        Hi,<c:out value="${nameAttr}"/>
    	
    </body>   
    </html>

XSS更详细的背景及方案，请参看：[http://www.cnblogs.com/flyingeagle/articles/6746732.html][http_www.cnblogs.com_flyingeagle_articles_6746732.html]

[http_www.cnblogs.com_flyingeagle_articles_6746732.html]: http://www.cnblogs.com/flyingeagle/articles/6746732.html