后台防XSS攻击

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Filter中对请求得参数进行过滤筛选

Filter配置如下

@WebFilter(urlPatterns = {"/web/*"},filterName = "xssFilter")    //urlPatterns为需要拦截的地址
public class XssFilter implements Filter {

    //不需要进行拦截的地址,一般会排除掉支付回调,具体业务具体分析
    private static final Set<String> ALLOWED_PATHS = Collections.unmodifiableSet(new HashSet<>(Arrays.asList("/pay/notifyWX"
            ,"/pay/notifyALI"
            ,"/express/notify/callback")));

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

    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)req;
        HttpServletResponse response = (HttpServletResponse)resp;
        //获取请求地址,将不需要过滤进行的地址排除
        String path = request.getRequestURI().substring(request.getContextPath().length()).replaceAll("[/]+$", "");
        boolean allowedPath = ALLOWED_PATHS.contains(path);
        if(allowedPath) {
            chain.doFilter(request, response);
        }else {
            chain.doFilter(new XSSRequestWrapper(request), response);
        }
    }

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
    }
}

RequestWrapper配置如下

想要改变在httpServletRequest中的参数,可以通过httpServletRequest的装饰类HttpServletRequestWrapper来实现,只需要在装饰类中按照需要重写其getParameter(getParameterValues)等方法即可。

public class XSSRequestWrapper extends HttpServletRequestWrapper {

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

    /**
     * 对数组参数进行特殊字符过滤
     */
    @Override
    public String[] getParameterValues(String name) {
        String[] values = super.getParameterValues(name);
        if (values == null) {
            return null;
        }
        int count = values.length;
        String[] encodedValues = new String[count];
        for (int i = 0; i < count; i++) {
            encodedValues[i] = clearXss(values[i]);
        }
        return encodedValues;
    }

    /**
     * 对参数中特殊字符进行过滤
     */
    @Override
    public String getParameter(String name) {
        String value = super.getParameter(name);
        if (value == null) {
            return null;
        }
        return clearXss(value);
    }

    /**
     * 获取attribute,特殊字符过滤
     */
    @Override
    public Object getAttribute(String name) {
        Object value = super.getAttribute(name);
        if (value instanceof String) {
            clearXss((String) value);
        }
        return value;
    }

    /**
     * 对请求头部进行特殊字符过滤
     */
    @Override
    public String getHeader(String name) {
        String value = super.getHeader(name);
        if (value == null) {
            return null;
        }
        return clearXss(value);
    }

    /**
     * 对body进行特殊字符过滤
     * @return
     * @throws IOException
     */
    @Override
    public ServletInputStream getInputStream() throws IOException {
        StringBuilder responseStrBuilder = new StringBuilder();
        BufferedReader streamReader = new BufferedReader(new InputStreamReader(super.getInputStream(), StandardCharsets.UTF_8));
        String inputStr;

        while ((inputStr = streamReader.readLine()) != null)
            responseStrBuilder.append(inputStr);

        if (SystemUtils.isNotEmpty(responseStrBuilder.toString())) {
            String clearXss = clearXss(responseStrBuilder.toString());
            final ByteArrayInputStream bais = new ByteArrayInputStream(clearXss.getBytes(StandardCharsets.UTF_8));
            return new ServletInputStream() {

                @Override
                public boolean isFinished() {
                    return false;
                }

                @Override
                public boolean isReady() {
                    return false;
                }

                @Override
                public void setReadListener(ReadListener readListener) {

                }

                @Override
                public int read() throws IOException {
                    return bais.read();
                }
            };
        }
        return super.getInputStream();
    }

    /**
     * @throws
     * @Title: clearXss
     * @Description: xss攻击处理
     * @param: @param value
     * @param: @return
     * @return: String
     */
    private String clearXss(String value) {
        if (SystemUtils.isEmpty(value)) {
            return value;
        }
        //编码
        value = new String(value.getBytes(StandardCharsets.UTF_8), StandardCharsets.UTF_8);

        return XssFilterUtil.stripXss(value);
    }
}

Xss工具类配置如下

@Slf4j
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[]{"</script>", Pattern.CASE_INSENSITIVE});
        ret.add(new Object[]{"<script(.*?)>",Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL});
        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) {
        System.out.println(value);
        if(SystemUtils.isNotEmpty(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("<", "&lt;").replaceAll(">", "&gt;");
            //删除特殊符号
            String specialStr = "%20|=|!=|-|--|;|'|\"|%|#|+|//|/| |\\|<|>|(|)|{|}";
            for (String str : specialStr.split("\\|")) {
                if(value.indexOf(str) > -1) {
                    value = value.replaceAll(str, "");
                }
            }
        }
      if (log.isDebugEnabled())
          log.debug("strip value: " + value);
        return value;
    }
}