一：跨站脚本的攻击
- XSS全称是Cross Site Scripting即跨站脚本，当目标网站目标用户浏览器渲染HTML文档的过程中，出现了不被预期的脚本指令并执行时，XSS就发生了。
这里我们主要注意四点：1、目标网站目标用户；2、浏览器；3、不被预期；4、脚本。
二：跨站脚本攻击的原理
主要是黑客可以通过修改传输的参数进行站点攻击，或者黑客通过盗取用户的信息进行站点攻击
三：跨站脚本攻击的预防措施
对于大部分的跨站攻击我们可以在程序的角度上进行解决，最常用的方法就是写一个过滤器
- 过滤配置类
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* filter配置类
*
* @author : lizhangyu
* @date : 2020-04-21
*/
@Configuration
public class FilterConfig {
@Bean
public FilterRegistrationBean registerXssFilter() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new XssFilter());
registration.addUrlPatterns("/*");
registration.setName("xssFilter");
registration.setOrder(1);
return registration;
}
}
- Xss过滤器类
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;
/**
* xss拦截器
*
* @author : lizhangyu
* @date : 2020-04-21
*/
@WebFilter(filterName = "XssFilter", urlPatterns = "/*")
public class XssFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// 包装request
XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper((HttpServletRequest) request);
chain.doFilter(xssRequest, response);
}
@Override
public void destroy() {
}
}
- 过滤器请求类
import com.lutongnet.cps.base.util.XssFilterUtil;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
/**
* @author : lizhangyu
* @date : 2020-04-21
*/
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
public XssHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
}
@Override
public String getParameter(String name) {
String string = super.getParameter(name);
// 返回值之前 先进行过滤
return XssFilterUtil.stripXss(string);
}
@Override
public String[] getParameterValues(String name) {
// 返回值之前 先进行过滤
String[] values = super
.getParameterValues(name);
if (values != null) {
for (int i = 0; i < values.length; i++) {
values[i] = XssFilterUtil.stripXss(values[i]);
}
}
return values;
}
}
- 过滤器工具类 （过滤的大多数条件）
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang.StringUtils;
/**
* Xss过滤工具类
* @author lizhangyu
* @version 1.0
* @date 2020/4/30 10:16
*/
public class XssFilterUtil {
private static List<Pattern> patterns = null;
private static List<Object[]> getXssPatternList() {
List<Object[]> ret = new ArrayList<Object[]>();
ret.add(new Object[] {
"<(no)?script[^>]*>.*?</(no)?script>",
Pattern.CASE_INSENSITIVE });
ret.add(new Object[] {
"eval\\((.*?)\\)",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] {
"expression\\((.*?)\\)",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] {
"(javascript:|vbscript:|view-source:)*",
Pattern.CASE_INSENSITIVE });
ret.add(new Object[] {
"<(\"[^\"]*\"|\'[^\']*\'|[^\'\">])*>",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] {
"(window\\.location|window\\.|\\.location|document\\.cookie|document\\.|alert\\(.*?\\)|window\\.open\\()*",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] {
"<+\\s*\\w*\\s*(oncontrolselect|oncopy|oncut|ondataavailable|ondatasetchanged|ondatasetcomplete|ondblclick|ondeactivate|ondrag|ondragend|ondragenter|ondragleave|ondragover|ondragstart|ondrop|οnerrοr=|onerroupdate|onfilterchange|onfinish|onfocus|onfocusin|onfocusout|onhelp|onkeydown|onkeypress|onkeyup|onlayoutcomplete|onload|onlosecapture|onmousedown|onmouseenter|onmouseleave|onmousemove|onmousout|onmouseover|onmouseup|onmousewheel|onmove|onmoveend|onmovestart|onabort|onactivate|onafterprint|onafterupdate|onbefore|onbeforeactivate|onbeforecopy|onbeforecut|onbeforedeactivate|onbeforeeditocus|onbeforepaste|onbeforeprint|onbeforeunload|onbeforeupdate|onblur|onbounce|oncellchange|onchange|onclick|oncontextmenu|onpaste|onpropertychange|onreadystatechange|onreset|onresize|onresizend|onresizestart|onrowenter|onrowexit|onrowsdelete|onrowsinserted|onscroll|onselect|onselectionchange|onselectstart|onstart|onstop|onsubmit|onunload)+\\s*=+",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
return ret;
}
private static List<Pattern> getPatterns() {
if (patterns == null) {
List<Pattern> list = new ArrayList<Pattern>();
String regex = null;
Integer flag = null;
int arrLength = 0;
for (Object[] arr : getXssPatternList()) {
arrLength = arr.length;
for (int i = 0; i < arrLength; i++) {
regex = (String) arr[0];
flag = (Integer) arr[1];
list.add(Pattern.compile(regex, flag));
}
}
patterns = list;
}
return patterns;
}
public static String stripXss(String value) {
if(StringUtils.isNotBlank(value)) {
Matcher matcher = null;
for(Pattern pattern : getPatterns()) {
matcher = pattern.matcher(value);
// 匹配
if(matcher.find()) {
// 删除相关字符串
value = matcher.replaceAll("");
}
}
value = value.replaceAll("<", "<").replaceAll(">", ">");
}
return value;
}
}
- 通过过滤器可以过滤大部分的跨站脚本攻击。