关于在doFilter设置XSS过滤防护的参考方案

说明

doFilter设置XSS过滤防护的方案可以在请求入口处做统一过滤,是一个能解决根本问题的方案。

关于过滤规则在第3个文件,其防护规则可以继续补充完善,也可以根据实际情况进行修改。

参考链接:https://www.cnblogs.com/yangxiong/p/8204038.html(预防XSS攻击,(参数/响应值)特殊字符过滤 - 余生莫度 - 博客园)

代码参考

  1. IllegalCharacterFilter.java
package com.lenovo.common.filter;
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;
/**
 * 非法字符过滤器,用来处理request.getParamater中的非法字符。如<script>alert('123');</script>
 */
public class IllegalCharacterFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {}
    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)req;
        request = new MHttpServletRequest(request);
        chain.doFilter(request, res);
    }
    @Override
    public void destroy() {}
}
  1. MHttpServletRequest.java
package com.lenovo.common.filter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import com.lenovo.common.utils.XssShieldUtil;
/**
 * 参数特殊字符过滤
 */
public class MHttpServletRequest extends HttpServletRequestWrapper {
    public MHttpServletRequest(HttpServletRequest request) {
        super(request);
    }
    @Override
    public String getParameter(String name) {
        // 返回值之前 先进行过滤
        return XssShieldUtil.stripXss(super.getParameter(XssShieldUtil.stripXss(name)));
    }
    @Override
    public String[] getParameterValues(String name) {
        // 返回值之前 先进行过滤
        String[] values = super.getParameterValues(XssShieldUtil.stripXss(name));
        if(values != null){
            for (int i = 0; i < values.length; i++) {
                values[i] = XssShieldUtil.stripXss(values[i]);
            }
        }
        return values;
    }
}
  1. XssShieldUtil.java
package com.lenovo.common.utils;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang.StringUtils;
/**
 * 处理非法字符
 */
public class XssShieldUtil {
    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|onerror=|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);
                if(matcher.find()) {  // 匹配
                    value = matcher.replaceAll(""); // 删除相关字符串
                }
            }
            value = value.replaceAll("<", "&lt;").replaceAll(">", "&gt;");
        }
        return value;
    }

    /**
     * 测试案例(可删除)
     */
    public static void main(String[] args) {
        String value = null;
        value = XssShieldUtil.stripXss("<script language=text/javascript>alert(document.cookie);</script>");
        System.out.println("type-1: '" + value + "'");
        value = XssShieldUtil.stripXss("<script src='' onerror='alert(document.cookie)'></script>");
        System.out.println("type-2: '" + value + "'");
        value = XssShieldUtil.stripXss("</script>");
        System.out.println("type-3: '" + value + "'");
        value = XssShieldUtil.stripXss(" eval(abc);");
        System.out.println("type-4: '" + value + "'");
        value = XssShieldUtil.stripXss(" expression(abc);");
        System.out.println("type-5: '" + value + "'");
        value = XssShieldUtil.stripXss("<img src='' onerror='alert(document.cookie);'></img>");
        System.out.println("type-6: '" + value + "'");
        value = XssShieldUtil.stripXss("<img src='' onerror='alert(document.cookie);'/>");
        System.out.println("type-7: '" + value + "'");
        value = XssShieldUtil.stripXss("<img src='' onerror='alert(document.cookie);'>");
        System.out.println("type-8: '" + value + "'");
        value = XssShieldUtil.stripXss("<script language=text/javascript>alert(document.cookie);");
        System.out.println("type-9: '" + value + "'");
        value = XssShieldUtil.stripXss("<script>window.location='url'");
        System.out.println("type-10: '" + value + "'");
        value = XssShieldUtil.stripXss(" onload='alert(\"abc\");");
        System.out.println("type-11: '" + value + "'");
        value = XssShieldUtil.stripXss("<img src=x<!--'<\"-->>");
        System.out.println("type-12: '" + value + "'");
        value = XssShieldUtil.stripXss("<=img onstop=");
        System.out.println("type-13: '" + value + "'");
    }
}

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