xss 防御

[xuyajun2013]

方法一：手动escape，例如用户可以输入：<script>alert()</script> 或者输入<h2>abc<h2>，如果有异常，显然有xss漏洞。
首先添加一个jar包：commons-lang-2.5.jar ，然后在后台调用这些函数：StringEscapeUtils.escapeHtml(string); StringEscapeUtils.escapeJavaScript(string); StringEscapeUtils.escapeSql(string)
前台js调用escape函数即可。

方法二：后台加Filter，对每个post请求的参数过滤一些关键字，替换成安全的，例如：< > ' " \ / # &
方法是实现一个自定义的HttpServletRequestWrapper，然后在Filter里面调用它，替换掉getParameter函数即可
首先添加一个XssHttpServletRequestWrapper
package com.ibm.web.beans;



import java.util.Enumeration;



import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletRequestWrapper;



public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {

public XssHttpServletRequestWrapper(HttpServletRequest servletRequest) {

super(servletRequest);

}

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;

}

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) {

//You'll need to remove the spaces from the html entities below

value = value.replaceAll("<", "& lt;").replaceAll(">", "& gt;");

value = value.replaceAll("\\(", "& #40;").replaceAll("\\)", "& #41;");

value = value.replaceAll("'", "& #39;");

value = value.replaceAll("eval\\((.*)\\)", "");

value = value.replaceAll("[\\\"\\\'][\\s]*javascript:(.*)[\\\"\\\']", "\"\"");

value = value.replaceAll("script", "");

return value;

}

}
然后添加一个过滤器XssFilter ：
package com.ibm.web.beans;



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 javax.servlet.http.HttpServletResponse;



public class XssFilter implements Filter {

FilterConfig filterConfig = null;



public void init(FilterConfig filterConfig) throws ServletException {

this.filterConfig = filterConfig;

}



public void destroy() {

this.filterConfig = null;

}

public void doFilter(ServletRequest request, ServletResponse response,

FilterChain chain) throws IOException, ServletException {

chain.doFilter(new XssHttpServletRequestWrapper(

(HttpServletRequest) request), response);

}

}

[xuyajun2013]

最后在web.xml里面配置一下，所有的请求的getParameter会被替换，如果参数里面 含有敏感词会被替换掉： <filter> <filter-name>XssSqlFilter</filter-name> <filter-class>com.ibm.web.beans.XssFilter</filter-class> </filter> <filter-mapping> <filter-name>XssSqlFilter</filter-name> <url-pattern>/*</url-pattern> <dispatcher>REQUEST</dispatcher> </filter-mapping>

[xuyajun2013]

参考网址：http://www.cnblogs.com/Mainz/archive/2012/11/01/2749874.html