本篇内容介绍了“如何使用springMVC通过Filter实现防止xss注入”的有关知识,在实际案例的操作过程中,不少人都会遇到这样的困境,接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读,能够学有所成!
跨站脚本工具(cross 斯特scripting),为不和层叠样式表(cascading style sheets,CSS)的缩写混淆,故将跨站脚本攻击缩写为XSS。
恶意攻击者往web页面里插入恶意scriptScript代码,当用户浏览该页之时,嵌入其中Web里面的Script代码会被执行,从而达到恶意攻击用户的目的。
防止XSS攻击简单的预防就是对Request请求中的一些参数去掉一些比较敏感的脚本命令。
原本是打算通过springMVC的HandlerInterceptor机制来实现的,通过获取request然后对request中的参数进行修改,结果虽然值修改了,但在Controller中获取的数值还是没有修改的。没办法就是要Filter来完成。
简单来说就是创建一个新的httpRequest类XsslHttpServletRequestWrapper,然后重写一些get方法(获取参数时对参数进行XSS判断预防)。
@WebFilter(filterName="xssMyfilter",urlPatterns="/*")
public class MyXssFilter implements Filter{
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
XsslHttpServletRequestWrapper xssRequest = new XsslHttpServletRequestWrapper((HttpServletRequest)request);
chain.doFilter(xssRequest , response);
}
@Override
public void destroy() {
}
}
XSS代码的过滤是在XsslHttpServletRequestWrapper中实现的,主要是覆盖实现了getParameter,getParameterValues,getHeader这几个方法,然后对获取的value值进行XSS处理。
public class XsslHttpServletRequestWrapper extends HttpServletRequestWrapper {
HttpServletRequest xssRequest = null;
public XsslHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
xssRequest = request;
}
@Override
public String getParameter(String name) {
String value = super.getParameter(replaceXSS(name));
if (value != null) {
value = replaceXSS(value);
}
return value;
}
@Override
public String[] getParameterValues(String name) {
String[] values = super.getParameterValues(replaceXSS(name));
if(values != null && values.length > 0){
for(int i =0; i< values.length ;i++){
values[i] = replaceXSS(values[i]);
}
}
return values;
}
@Override
public String getHeader(String name) {
String value = super.getHeader(replaceXSS(name));
if (value != null) {
value = replaceXSS(value);
}
return value;
}
/**
* 去除待带script、src的语句,转义替换后的value值
*/
public static String replaceXSS(String value) {
if (value != null) {
try{
value = value.replace("+","%2B"); //'+' replace to '%2B'
value = URLDecoder.decode(value, "utf-8");
}catch(UnsupportedEncodingException e){
}catch(IllegalArgumentException e){
}
// Avoid null characters
value = value.replaceAll("\0", "");
// Avoid anything between script tags
Pattern scriptPattern = Pattern.compile("<script>(.*?)</script>", Pattern.CASE_INSENSITIVE);
value = scriptPattern.matcher(value).replaceAll("");
// Avoid anything in a src='...' type of e­xpression
scriptPattern = Pattern.compile("src[\r\n]*=[\r\n]*\\\'(.*?)\\\'", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
value = scriptPattern.matcher(value).replaceAll("");
scriptPattern = Pattern.compile("src[\r\n]*=[\r\n]*\\\"(.*?)\\\"", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
value = scriptPattern.matcher(value).replaceAll("");
// Remove any lonesome </script> tag
scriptPattern = Pattern.compile("</script>", Pattern.CASE_INSENSITIVE);
value = scriptPattern.matcher(value).replaceAll("");
// Remove any lonesome <script ...> tag
scriptPattern = Pattern.compile("<script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
value = scriptPattern.matcher(value).replaceAll("");
// Avoid eval(...) e­xpressions
scriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
value = scriptPattern.matcher(value).replaceAll("");
// Avoid e­xpression(...) e­xpressions
scriptPattern = Pattern.compile("e­xpression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
value = scriptPattern.matcher(value).replaceAll("");
// Avoid javascript:... e­xpressions
scriptPattern = Pattern.compile("javascript:", Pattern.CASE_INSENSITIVE);
value = scriptPattern.matcher(value).replaceAll("");
// Avoid alert:... e­xpressions
scriptPattern = Pattern.compile("alert", Pattern.CASE_INSENSITIVE);
value = scriptPattern.matcher(value).replaceAll("");
// Avoid οnlοad= e­xpressions
scriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
value = scriptPattern.matcher(value).replaceAll("");
scriptPattern = Pattern.compile("vbscript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);
value = scriptPattern.matcher(value).replaceAll("");
}
return filter(value);
}
/**
* 过滤特殊字符
*/
public static String filter(String value) {
if (value == null) {
return null;
}
StringBuffer result = new StringBuffer(value.length());
for (int i=0; i<value.length(); ++i) {
switch (value.charAt(i)) {
case '<':
result.append("<");
break;
case '>':
result.append(">");
break;
case '"':
result.append(""");
break;
case '\'':
result.append("'");
break;
case '%':
result.append("%");
break;
case ';':
result.append(";");
break;
case '(':
result.append("(");
break;
case ')':
result.append(")");
break;
case '&':
result.append("&");
break;
case '+':
result.append("+");
break;
default:
result.append(value.charAt(i));
break;
}
}
return result.toString();
}
}
xss过滤请求的参数:Content-Type为 json(application/json)
SpringMVC 对于application/json 转换处理说明:
spring mvc默认使用MappingJackson2HttpMessageConverter转换器,
而它是使用jackson来序列化对象的,如果我们能 将jackson的序列化和反序列化过程修改,加入过滤xss代码,并将其注册到MappingJackson2HttpMessageConverter中
import java.io.IOException;
import org.apache.commons.text.StringEscapeUtils;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
/**
* 反序列化
*
*/
public class XssDefaultJsonDeserializer extends StdDeserializer<String> {
public XssDefaultJsonDeserializer(){
this(null);
}
public XssDefaultJsonDeserializer(Class<String> vc) {
super(vc);
}
@Override
public String deserialize(JsonParser jsonParser, DeserializationContext ctxt) throws IOException, JsonProcessingException {
// TODO Auto-generated method stub
//return StringEscapeUtils.escapeEcmaScript(jsonParser.getText());
return StringEscapeUtils.unescapeHtml4(jsonParser.getText());
}
}
@Configuration
@EnableWebMvc
public class SpingMVCConfig extends WebMvcConfigurerAdapter {
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
super.configureMessageConverters(converters);
// TODO Auto-generated method stub
SimpleModule module = new SimpleModule();
// 反序列化
module.addDeserializer(String.class, new XssDefaultJsonDeserializer());
// 序列化
module.addSerializer(String.class, new XssDefaultJsonSerializer());
ObjectMapper mapper = Jackson2ObjectMapperBuilder.json().build();
// 注册自定义的序列化和反序列化器
mapper.registerModule(module);
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter(mapper);
converters.add(converter);
}
}
“如何使用springMVC通过Filter实现防止xss注入”的内容就介绍到这里了,感谢大家的阅读。如果想了解更多行业相关的知识可以关注亿速云网站,小编将为大家输出更多高质量的实用文章!
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