JSP spring boot / cloud 使用filter防止XSS
一.前言
XSS(跨站腳本攻擊)
跨站腳本攻擊(Cross Site Scripting)，為不和層疊樣式表(Cascading Style Sheets, CSS)的縮寫混淆，故將跨站腳本攻擊縮寫為XSS。惡意攻擊者往Web頁面里插入惡意Script代碼，當用戶瀏覽該頁之時，嵌入其中Web里面的Script代碼會被執行，從而達到惡意攻擊用戶的目的。
二.思路
基于filter攔截,將特殊字符替換為html轉意字符 (如: "<" 轉意為 "<") , 需要攔截的點如下:
三.實現
1.創建XssHttpServletRequestWrapper類
在獲取請求頭,請求參數的這些地方,將目標值使用HtmlUtils.htmlEscape方法轉意為html字符,而避免惡意代碼參與到后續的流程中
/** * XssHttpServletRequestWrapper.java * Created at 2016-09-19 * Created by wangkang * Copyright (C) 2016 egridcloud.com, All rights reserved. */package com.egridcloud.udf.core.xss;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRequestWrapper;import org.springframework.web.util.HtmlUtils;/** * 描述 : 跨站請求防范 * * @author wangkang * */public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper { /** * 描述 : 構造函數 * * @param request 請求對象 */ public XssHttpServletRequestWrapper(HttpServletRequest request) { super(request); } @Override public String getHeader(String name) { String value = super.getHeader(name); return HtmlUtils.htmlEscape(value); } @Override public String getParameter(String name) { String value = super.getParameter(name); return HtmlUtils.htmlEscape(value); } @Override public String[] getParameterValues(String name) { String[] values = super.getParameterValues(name); if (values != null) { int length = values.length; String[] escapseValues = new String[length]; for (int i = 0; i < length; i++) { escapseValues[i] = HtmlUtils.htmlEscape(values[i]); } return escapseValues; } return super.getParameterValues(name); }}2.創建XssStringJsonSerializer類
其次是涉及到json轉換的地方,也一樣需要進行轉意,比如,rerquestBody,responseBody
/** * XssStringJsonSerializer.java * Created at 2016-09-19 * Created by wangkang * Copyright (C) 2016 egridcloud.com, All rights reserved. */package com.egridcloud.udf.core.xss;import java.io.IOException;import org.springframework.web.util.HtmlUtils;import com.fasterxml.jackson.core.JsonGenerator;import com.fasterxml.jackson.databind.JsonSerializer;import com.fasterxml.jackson.databind.SerializerProvider;/** * 描述 : 基于xss的JsonSerializer * * @author wangkang * */public class XssStringJsonSerializer extends JsonSerializer<String> { @Override public Class<String> handledType() { return String.class; } @Override public void serialize(String value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException { if (value != null) { String encodedValue = HtmlUtils.htmlEscape(value); jsonGenerator.writeString(encodedValue); } }}3.創建Bean
在啟動類中,創建XssObjectMapper的bean,替換spring boot原有的實例,用于整個系統的json轉換.
/** * 描述 : xssObjectMapper * * @param builder builder * @return xssObjectMapper */ @Bean @Primary public ObjectMapper xssObjectMapper(Jackson2ObjectMapperBuilder builder) { //解析器 ObjectMapper objectMapper = builder.createXmlMapper(false).build(); //注冊xss解析器 SimpleModule xssModule = new SimpleModule("XssStringJsonSerializer"); xssModule.addSerializer(new XssStringJsonSerializer()); objectMapper.registerModule(xssModule); //返回 return objectMapper; }4.創建XssFilter
首先是攔截所有的請求,然后在doFilter方法中,將HttpServletRequest強制類型轉換成XssHttpServletRequestWrapper
然后傳遞下去.
/** * XssFilter.java * Created at 2016-09-19 * Created by wangkang * Copyright (C) 2016 egridcloud.com, All rights reserved. */package com.egridcloud.udf.core.xss;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;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * 描述 : 跨站請求防范 * * @author wangkang * */@WebFilter(filterName = "xssFilter", urlPatterns = "/*", asyncSupported = true)public class XssFilter implements Filter { /** * 描述 : 日志 */ private static final Logger LOGGER = LoggerFactory.getLogger(XssFilter.class); @Override public void init(FilterConfig filterConfig) throws ServletException { LOGGER.debug("(XssFilter) initialize"); } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper((HttpServletRequest) request); chain.doFilter(xssRequest, response); } @Override public void destroy() { LOGGER.debug("(XssFilter) destroy"); }}四.結束
本文雖基于spring boot實現主題,但是思路是一致的,不限于任何框架.
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