XSS安全漏洞修复解决方案

背景：等保测评公司针对我系统进行了一次渗透测试，并发现存在XSS漏洞，现记录修复过程。

框架：SSM。

全站XSS：

漏洞风险等级：中危

涉及页面：全站存在内容输入处

漏洞描述：所有模块可以修改内容处存在XSS，填入恶意代码后触发。 

修复建议：过滤所有输入内容。（防止恶意弹窗/跨站脚本/过滤敏感字符/违法信息等）

 

 

解决方案

列举方案1：写个DispatcherServlet

import javax.servlet.http.HttpServletRequest;

import org.springframework.stereotype.Controller;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.HandlerExecutionChain;

@SuppressWarnings("serial")
public class DispatcherServletWrapper extends DispatcherServlet {
	
	@Override
	protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
		HandlerExecutionChain chain = super.getHandler(request);
		Object handler = chain.getHandler();
        if (!(handler instanceof HandlerMethod)) {
            return chain;
        }
		
        HandlerMethod hm = (HandlerMethod)handler;
        if (!hm.getBeanType().isAnnotationPresent(Controller.class)) {
        	return chain;
        }
        
        //仅处理@Controller注解的Bean
		return new HandlerExecutionChainWrapper(chain,request,getWebApplicationContext());
	}
	
}

在getHandler中返回HandlerExecutionChainWrapper

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.ReflectionUtils.FieldCallback;
import org.springframework.util.ReflectionUtils.FieldFilter;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerExecutionChain;
import org.springframework.web.util.HtmlUtils;

public class HandlerExecutionChainWrapper extends HandlerExecutionChain {
	 
	private BeanFactory beanFactory;
	private HttpServletRequest request;
	private HandlerMethod handlerWrapper;
	private byte[] lock = new byte[0];
	
	public HandlerExecutionChainWrapper(HandlerExecutionChain chain,
			HttpServletRequest request,
			BeanFactory beanFactory) {
		super(chain.getHandler(),chain.getInterceptors());
		this.request = request;
		this.beanFactory = beanFactory;
	}
 
	@Override
	public Object getHandler() {
		if (handlerWrapper != null) {
			return handlerWrapper;
		}
		
		synchronized (lock) {
			if (handlerWrapper != null) {
				return handlerWrapper;
			}
			HandlerMethod superMethodHandler = (HandlerMethod)super.getHandler();
			Object proxyBean = createProxyBean(superMethodHandler);
			handlerWrapper = new HandlerMethod(proxyBean,superMethodHandler.getMethod());
			return handlerWrapper;
		}
		
	}
	
	/**
	 * 为Controller Bean创建一个代理实例,以便用于 实现调用真实Controller Bean前的切面拦截
	 * 用以过滤方法参数中可能的XSS注入
	 * @param handler
	 * @return
	 */
	private Object createProxyBean(HandlerMethod handler) {
		try {
			Enhancer enhancer = new Enhancer();
			enhancer.setSuperclass(handler.getBeanType());
			Object bean = handler.getBean();
			if (bean instanceof String) {
				bean = beanFactory.getBean((String)bean);
			}
			ControllerXssInterceptor xss = new ControllerXssInterceptor(bean);
			xss.setRequest(this.request);
			enhancer.setCallback(xss);
			return enhancer.create();
		}catch(Exception e) {
			throw new IllegalStateException("为Controller创建代理失败:"+e.getMessage(), e);
		}
	}
	
	
	public static class ControllerXssInterceptor implements MethodInterceptor {
 
		private Object target;
		private HttpServletRequest request;
		private List objectMatchPackages;
		
		public ControllerXssInterceptor(Object target) {
			this.target = target;
			this.objectMatchPackages = new ArrayList();
			this.objectMatchPackages.add("com.jwell");
		}
		
		public void setRequest(HttpServletRequest request) {
			this.request = request;
		}
 
 
		@Override
		public Object intercept(Object obj, Method method, Object[] args, 
				MethodProxy proxy) 
				throws Throwable {
			
			//对Controller的方法参数进行调用前处理
			//过滤String类型参数中可能存在的XSS注入
			if (args != null) {
				for (int i=0;i

web.xml 替换DispatcherServlet

    SpringMVC
    
    
     org.springframework.web.servlet.DispatcherServlet 
    
      contextConfigLocation
      classpath:spring-mvc-bpbj.xml
    
    1
    true
  

再次测试，已解决，不过此方案本人不推荐，原因（会影响业务，谁用谁知道 哈哈~）

列举方案2：写个filter（推荐）

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;

public class XssFilter implements Filter{

	FilterConfig filterConfig = null;
	
	@Override
	public void destroy() {
		// TODO Auto-generated method stub
		 this.filterConfig = null;
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
		// TODO Auto-generated method stub
		 chain.doFilter(new XssShellInterceptor( (HttpServletRequest) request), response);
	}

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		// TODO Auto-generated method stub
		 this.filterConfig = filterConfig;
	}

XssShellInterceptor类（HttpServletRequestWrapper）

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

public class XssShellInterceptor extends HttpServletRequestWrapper{

	public XssShellInterceptor(HttpServletRequest request) {
		super(request);
	}

	
	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);
	    }
	    
	    //过滤规则 目前我只配了过滤 script 
	    private String cleanXSS(String value) {
	        //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;
	    }
	
}

web.xml 添加filter

    	XssFilter
     	com.xx.xx.bmms.web.filter.XssFilter
  
  
	   XssFilter
       /*  
   

再次测试，已解决。注意：如果web.xml中有多个filter 注意执行顺序。