跨站脚本攻击的原理 XSS又叫CSS (Cross Site Script) ，跨站脚本攻击。它指的是恶意攻击者往Web页面里插入恶意脚本代码，而程序对于用户输入内容未过滤，当用户浏览该页之时，嵌入其中Web里面的脚本代码会被执行，从而达到恶意攻击用户的特殊目的。
跨站脚本攻击的危害：窃取cookie、放蠕虫、网站钓鱼 …
跨站脚本攻击的分类主要有：存储型XSS、反射型XSS、DOM型XSS
SQL注入攻击的原理： 使用用户输入的参数拼凑SQL查询语句，使用户可以控制SQL查询语句。 比如：{"id":"1' and exp(if(user() like 0x5a535748403137322e33302e31312e313425,1,1111)) or '1'='1","pageQuery":{"current":"2","size":"6"}}
XSS漏洞及SQL注入过滤器参考：
1、XssFilter
package com.eshore.zswh.common.support.filter;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* XSS过滤器
*
* @author cp
* @date 2022/8/5
*/
public class XssFilter implements Filter {
// 忽略权限检查的url地址
private final String[] excludeUrls = new String[]{
"null"
};
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) arg0;
HttpServletResponse response = (HttpServletResponse) arg1;
String pathInfo = req.getPathInfo() == null ? "" : req.getPathInfo();
//获取请求url的后两层
String url = req.getServletPath() + pathInfo;
//获取请求你ip后的全部路径
String uri = req.getRequestURI();
//注入xss过滤器实例
XssHttpServletRequestWraper req = new XssHttpServletRequestWraper(req);
//过滤掉不需要的Xss校验的地址
for (String str : excludeUrls) {
if (uri.indexOf(str) >= 0) {
arg2.doFilter(arg0, response);
return;
}
}
//过滤
arg2.doFilter(req, response);
}
@Override
public void destroy() {
}
}
2、XssHttpServletRequestWraper
package com.eshore.zswh.common.support.filter;
import com.eshore.zswh.common.exception.ApiException;
import lombok.extern.slf4j.Slf4j;
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
@Slf4j
public class XssHttpServletRequestWraper extends HttpServletRequestWrapper {
public XssHttpServletRequestWraper() {
super(null);
}
public XssHttpServletRequestWraper(HttpServletRequest httpservletrequest) {
super(httpservletrequest);
}
//过滤springmvc中的 @RequestParam 注解中的参数
public String[] getParameterValues(String s) {
String str[] = super.getParameterValues(s);
if (str == null) {
return null;
}
int i = str.length;
String as1[] = new String[i];
for (int j = 0; j < i; j++) {
//System.out.println("getParameterValues:"+str[j]);
as1[j] = cleanXSS(cleanSQLInject(str[j]));
}
log.info("XssHttpServletRequestWraper净化后的请求为：==========" + as1);
return as1;
}
//过滤request.getParameter的参数
public String getParameter(String s) {
String s1 = super.getParameter(s);
if (s1 == null) {
return null;
} else {
String s2 = cleanXSS(cleanSQLInject(s1));
log.info("XssHttpServletRequestWraper净化后的请求为：==========" + s2);
return s2;
}
}
//过滤请求体 json 格式的
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream bais = new ByteArrayInputStream(inputHandlers(super.getInputStream ()).getBytes ());
return new ServletInputStream() {
@Override
public int read() throws IOException {
return bais.read();
}
public boolean isFinished() {
return false;
}
public boolean isReady() {
return false;
}
public void setReadListener(ReadListener readListener) { }
};
}
public String inputHandlers(ServletInputStream servletInputStream){
StringBuilder sb = new StringBuilder();
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(servletInputStream, Charset.forName("UTF-8")));
String line = "";
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (servletInputStream != null) {
try {
servletInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return cleanXSS(sb.toString ());
}
public String cleanXSS(String src) {
String temp = src;
src = src.replaceAll("<", "＜").replaceAll(">", "＞");
src = src.replaceAll("\(", "（").replaceAll("\)", "）");
src = src.replaceAll("'", "＇");
src = src.replaceAll(";", "；");
/**-----------------------start--------------------------*/
src = src.replaceAll("<", "& lt;").replaceAll(">", "& gt;");
src = src.replaceAll("\(", "& #40;").replaceAll("\)", "& #41");
src = src.replaceAll("eval\((.*)\)", "");
src = src.replaceAll("[\"\'][\s]*javascript:(.*)[\"\']", """");
src = src.replaceAll("script", "");
src = src.replaceAll("link", "");
src = src.replaceAll("frame", "");
/**-----------------------end--------------------------*/
Pattern pattern = Pattern.compile("(eval\((.*)\)|script)",
Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(src);
src = matcher.replaceAll("");
pattern = Pattern.compile("[\"\'][\s]*javascript:(.*)[\"\']",
Pattern.CASE_INSENSITIVE);
matcher = pattern.matcher(src);
src = matcher.replaceAll("""");
// 增加脚本
src = src.replaceAll("script", "").replaceAll(";", "")
/*.replaceAll(""", "").replaceAll("@", "")*/
.replaceAll("0x0d", "").replaceAll("0x0a", "");
if (!temp.equals(src)) {
// System.out.println("输入信息存在xss攻击！");
// System.out.println("原始输入信息-->" + temp);
// System.out.println("处理后信息-->" + src);
log.error("xss攻击检查：参数含有非法攻击字符，已禁止继续访问！！");
log.error("原始输入信息-->" + temp);
throw new ApiException("xss攻击检查：参数含有非法攻击字符，已禁止继续访问！！");
}
return src;
}
//输出
public void outputMsgByOutputStream(HttpServletResponse response, String msg) throws IOException {
ServletOutputStream outputStream = response.getOutputStream(); //获取输出流
response.setHeader("content-type", "text/html;charset=UTF-8"); //通过设置响应头控制浏览器以UTF-8的编码显示数据，如果不加这句话，那么浏览器显示的将是乱码
byte[] dataByteArr = msg.getBytes("UTF-8");// 将字符转换成字节数组，指定以UTF-8编码进行转换
outputStream.write(dataByteArr);// 使用OutputStream流向客户端输出字节数组
}
// 需要增加通配，过滤大小写组合
public String cleanSQLInject(String src) {
String lowSrc = src.toLowerCase();
String temp = src;
String lowSrcAfter = lowSrc.replaceAll("insert", "forbidI")
.replaceAll("select", "forbidS")
.replaceAll("update", "forbidU")
.replaceAll("delete", "forbidD").replaceAll("and", "forbidA")
.replaceAll("or", "forbidO");
if (!lowSrcAfter.equals(lowSrc)) {
log.error("sql注入检查：输入信息存在SQL攻击！");
log.error("原始输入信息-->" + temp);
log.error("处理后信息-->" + lowSrc);
throw new ApiException("sql注入检查：参数含有非法攻击字符，已禁止继续访问！！");
}
return src;
}
}
