背景

近期项目上线，甲方要求通过安全检测才能进行验收，故针对扫描结果对系统进行了一系列的安全加固，本文对一些常见的安全问题及防护策略进行介绍，提供对应的解决方案

跨站脚本攻击

XSS常发生于论坛评论等系统，现在富文本编辑器已对XSS进行了防护，但是我们任需要在后端接口进行数据过滤,

常见防护策略是通过过滤器将恶意提交的脚本进行过滤与替换

public class XSSFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        //System.out.println("XSSFilter");
        String contentType = request.getContentType();
        if (StringUtils.isNotBlank(contentType) && contentType.contains("application/json")) {
            XSSBodyRequestWrapper xssBodyRequestWrapper = new XSSBodyRequestWrapper((HttpServletRequest) request);
            chain.doFilter(xssBodyRequestWrapper, response);
        } else {
            chain.doFilter(request, response);
        }
    }
}

public class XSSBodyRequestWrapper extends HttpServletRequestWrapper {

    private String body;

    public XSSBodyRequestWrapper(HttpServletRequest request) {
        super(request);
        try{
            body = XSSScriptUtil.handleString(CommonUtil.getBodyString(request));
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {

        final ByteArrayInputStream bais = new ByteArrayInputStream(body.getBytes(Charset.forName("UTF-8")));

        return new ServletInputStream() {

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

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

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

            @Override
            public void setReadListener(ReadListener readListener) {

            }
        };
    }

}

public class XSSScriptUtil {
    public static String handleString(String value) {
        if (value != null) {
            Pattern scriptPattern = Pattern.compile("<script>(\\s*.*?)</script>",
                    Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("-");
            scriptPattern = Pattern.compile("</script(\\s*.*?)>",
                    Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("-");
            scriptPattern = Pattern.compile("<script(\\s*.*?)>",
                    Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
                            | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("-");
            scriptPattern = Pattern.compile("eval\\((.*?)\\)",
                    Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
                            | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("-");
            scriptPattern = Pattern.compile("e­xpression\\((.*?)\\)",
                    Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
                            | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("-");
            scriptPattern = Pattern.compile("javascript:",
                    Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("-");
            scriptPattern = Pattern.compile("vbscript:",
                    Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("-");
            scriptPattern = Pattern.compile("onload(.*?)=",
                    Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
                            | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("-");


            scriptPattern = Pattern.compile("<+.*(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)+.*=+",
                    Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
                            | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("-");



            // 过滤emoji表情
            scriptPattern = Pattern
                    .compile(
                            "[\ud83c\udc00-\ud83c\udfff]|[\ud83d\udc00-\ud83d\udfff]|[\u2600-\u27ff]",
                            Pattern.UNICODE_CASE | Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("-");
        }
        return value;
    }
}

SQL注入

sql注入是系统最常见的安全问题之一，会导致登陆安全，数据访问权限安全等，常见策略除了对sql语句保持参数化编写外，我们也需要使用拦截器对与提交参数进行检测，出现敏感字符进行错误提示

@Component
public class SQLInjectInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //System.out.println("SQLInjectInterceptor");
        boolean isvalid = true;
        String contentType = request.getContentType();
        if (StringUtils.isNotBlank(contentType) && contentType.contains("application/json")) {
            String body = CommonUtil.getBodyString(request);
            try {
                Object object = JSON.parse(body);
                if (object instanceof JSONObject) {
                    JSONObject jsonObject = JSONObject.parseObject(body);
                    for (Map.Entry<String, Object> item : jsonObject.entrySet()) {
                        String value = ConvertOp.convert2String(item.getValue());
                        if (SQLInjectUtil.checkSQLInject(value)) {
                            isvalid = false;
                            break;
                        }
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        if (!isvalid) {
            response.sendRedirect(request.getContextPath() + "/frame/error/sqlInjectionError");
        }
        return isvalid;
    }

}

public class SQLInjectUtil {
    public static String keyWord = "select|update|delete|insert|truncate|declare|cast|xp_cmdshell|count|char|length|sleep|master|mid|and|or";

    public static boolean checkSQLInject(String value) {
        boolean flag = false;
        value = ConvertOp.convert2String(value).toLowerCase().trim();
        if (!StringUtil.isEmpty(value) && !StringUtil.checkIsOnlyContainCharAndNum(value)) {
            List<String> keyWordList = Arrays.asList(keyWord.split("\\|"));
            for (String ss : keyWordList) {
                if (value.contains(ss)) {
                    if (StringUtil.checkFlowChar(value, ss, " ", true) ||
                            StringUtil.checkFlowChar(value, ss, "(", true) ||
                            StringUtil.checkFlowChar(value, ss, CommonUtil.getNewLine(), true)) {
                        flag = true;
                        break;
                    }
                }
            }
        }
        return flag;
    }
}

HTTP请求方法限制

我们应该只保留系统需要的请求方法，其它方法例如DELETE，PUT，TRACE等会造成系统数据泄露或破坏，一般在运行容器中配置即可，针对jar包运行的项目，因为使用了内置的tomcat，所以需要单独的配置文件代码进行控制

@Configuration
public class TomcatConfig {
    @Bean
    public TomcatServletWebServerFactory servletContainer() {
        TomcatServletWebServerFactory tomcatServletContainerFactory = new TomcatServletWebServerFactory() {
            @Override
            protected void postProcessContext(Context context) {
                SecurityConstraint constraint = new SecurityConstraint();
                SecurityCollection collection = new SecurityCollection();
                //http方法
                List<String> forbiddenList = Arrays.asList("PUT|DELETE|HEAD|TRACE".split("\\|"));
                for (String method:forbiddenList) {
                    collection.addMethod(method);
                }
                //url匹配表达式
                collection.addPattern("/*");
                constraint.addCollection(collection);
                constraint.setAuthConstraint(true);
                context.addConstraint(constraint );
                //设置使用httpOnly
                context.setUseHttpOnly(true);
            }
        };
        tomcatServletContainerFactory.addConnectorCustomizers(connector -> {
            connector.setAllowTrace(true);
        });
        return tomcatServletContainerFactory;
    }

}

用户权限

密码加密

针对用户密码需要进行密文存储，保证数据安全，常用MD5算法，因为MD5的加密结果的固定性，我们需要在加密时加入盐来保证每个密码密文的唯一性，我们采用的是MD5（密码+“|”+登录名）的方式，同时针对加密内容存在中文的情况下完善处理，避免前后端MD5加密结果不一致的情况

public class EncryptUtil {
    public static String encryptByMD5(String str) throws NoSuchAlgorithmException, UnsupportedEncodingException {
        //生成md5加密算法
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        md5.update(str.getBytes("UTF-8"));
        byte b[] = md5.digest();
        int i;
        StringBuffer buf = new StringBuffer("");
        for (int j = 0; j < b.length; j++) {
            i = b[j];
            if (i < 0)
                i += 256;
            if (i < 16)
                buf.append("0");
            buf.append(Integer.toHexString(i));
        }
        String md5_32 = buf.toString();		//32位加密   与mysql的MD5函数结果一致。
//        String md5_16 = buf.toString().substring(8, 24);	//16位加密
        return md5_32;
    }
}

登陆验证码

登陆验证码我们是基于redis来实现的，传统session实现方式会在chrome高版本跨域情况下有所限制

验证码实现方式就是生成随机字符，根据随机字符生成对应Base64图片，将图片返回给前端，字符存储Redis中并设置过期时间

@Component
public class ValidateCodeUtil {
    private static Random random = new Random();
    private int width = 165; //验证码的宽
    private int height = 45; //验证码的高
    private int lineSize = 30; //验证码中夹杂的干扰线数量
    private int randomStrNum = 4; //验证码字符个数

    private String randomString = "0123456789";
    private final String sessionKey = "ValidateCode";

    private int validDBIndex = 2;
    @Autowired
    RedisUtil redisUtil;

    @Autowired
    private FrameConfig frameConfig;

    public String getBase64ValidateImage(String key) {
        ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();
        g.fillRect(0, 0, width, height);
        g.setColor(getRandomColor(105, 189));
        g.setFont(getFont());
        //干扰线
        for (int i = 0; i < lineSize; i++) {
            drawLine(g);
        }

        //随机字符
        String randomStr = "";
        for (int i = 0; i < randomStrNum; i++) {
            randomStr = drawString(g, randomStr, i);
        }
        g.dispose();
        redisUtil.redisTemplateSetForList(key,sessionKey,randomStr,validDBIndex);
        redisUtil.setExpire(key, frameConfig.getValidatecode_expireseconds(),TimeUnit.SECONDS,validDBIndex);
        String base64String = "";
        try {
            //  直接返回图片
            //  ImageIO.write(image, "PNG", response.getOutputStream());
            //返回 base64
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ImageIO.write(image, "PNG", bos);
            byte[] bytes = bos.toByteArray();
            Base64.Encoder encoder = Base64.getEncoder();
            base64String = encoder.encodeToString(bytes);

        } catch (Exception e) {
            e.printStackTrace();
        }

        return base64String;
    }

    public String checkValidate(String key,String code){
        String errorMessage = "";
        if(redisUtil.isValid(key,validDBIndex)){
            String sessionCode = ConvertOp.convert2String(redisUtil.redisTemplateGetForList(key,sessionKey,validDBIndex));
            if(!code.toLowerCase().equals(sessionCode)){
                errorMessage = "验证码不正确";
            }
        }else{
            errorMessage = "验证码已过期";
        }
        return errorMessage;
    }

    //颜色的设置
    private  Color getRandomColor(int fc, int bc) {
        fc = Math.min(fc, 255);
        bc = Math.min(bc, 255);
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 12);

        return new Color(r, g, b);
    }

    //字体的设置
    private Font getFont() {
        return new Font("Times New Roman", Font.ROMAN_BASELINE, 40);
    }

    //干扰线的绘制
    private void drawLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(20);
        int yl = random.nextInt(10);
        g.drawLine(x, y, x + xl, y + yl);

    }
    //随机字符的获取
    private  String getRandomString(int num){
        num = num > 0 ? num : randomString.length();
        return String.valueOf(randomString.charAt(random.nextInt(num)));
    }
    //字符串的绘制
    private String drawString(Graphics g, String randomStr, int i) {
        g.setFont(getFont());
        g.setColor(getRandomColor(108, 190));
        //System.out.println(random.nextInt(randomString.length()));
        String rand = getRandomString(random.nextInt(randomString.length()));
        randomStr += rand;
        g.translate(random.nextInt(3), random.nextInt(6));
        g.drawString(rand, 40 * i + 10, 25);
        return randomStr;
    }
}

踢人下线

此功能保证一个用户账号只能在同一个相同类型的设备上登陆，不同设备重复登陆，则其他登陆机器自动下,所以我们需要存储用户的登陆情况，表结构设计如下，LoginFrom标识登陆来源，比如电脑，移动端，大屏机等等，自动下线操作可以采用websoket监听通知

CREATE TABLE `f_online` (
  `UnitGuid` varchar(50) NOT NULL,
  `UserGuid` varchar(50) DEFAULT NULL,
  `UserName` varchar(100) DEFAULT NULL,
  `LoginFrom` varchar(50) DEFAULT NULL,
  `LoginDate` datetime DEFAULT NULL,
  `LoginToken` varchar(100) DEFAULT NULL,
  `ReserveA` varchar(100) DEFAULT NULL,
  `ReserveB` varchar(100) DEFAULT NULL,
  `ReserveC` varchar(100) DEFAULT NULL,
  `ReserveD` varchar(100) DEFAULT NULL,
  `SpareX` varchar(100) DEFAULT NULL,
  `SpareY` varchar(100) DEFAULT NULL,
  `SpareZ` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`UnitGuid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

登陆错误锁定

为了避免恶意尝试密码登陆，我们需要对在一定时间内登陆错误的用户进行临时的锁定，我们结合登陆日志，例如如果在1分钟内登陆失败超过5此，则进行账户锁定1分钟，将锁定的key根据用户名生成存入redis中，设置锁定时间，在下次登陆时首先检查是否有对应的锁即可

Druid设置

系统在集成Druid线程池时，会默认有监控页面暴露，我们要做好登陆权限设置，避免数据库信息泄露

    @Bean
    public ServletRegistrationBean druidServlet() {
        ServletRegistrationBean reg = new ServletRegistrationBean();
        reg.setServlet(new StatViewServlet());
        reg.addUrlMappings("/druid/*");
        reg.addInitParameter("allow", ""); //白名单
        reg.addInitParameter("loginUsername", "admin");
        reg.addInitParameter("loginPassword", "11111");
        return reg;
    }