> For the complete documentation index, see [llms.txt](https://krjaeh0.gitbook.io/j-log/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://krjaeh0.gitbook.io/j-log/security/bwapp/html-injection-reflected_get.md).

# HTML Injection   Reflected\_GET

## Low

html 코드의 삽입 취약점이 있는 것을 알 수 있음

사용자의 입력을 저장하는 파라미터에 위약함을 알 수 있다.

## Medium

문자열로 처리된다.

## Check

### low\_level

### Medium

<: gt\
\>: lt

[아스크코드](https://www.ascii-code.com/)로 인코딩해 입력하면 될 것 같다. = [URL 인코딩](file:///2237607/security/DoubleEncoding.md)

<details>

<summary>인코딩 예시</summary>

```
<h1>hello</h1> = %3ch1%3ehello%3c%2fh1%3e
```

</details>

* html은 입력을 서버에 넘길때 아스키 코드로 인코딩해 전달
* 서버는 받은 입력을 디코딩
* 두 값의 비교는 인코딩 전 입력 값으로 비교하기 때문에 먼저 인코딩하여 전달할 경우 처리를 우회할 수 있게 된다.

### high

{% hint style="info" %}
html injection을 방어하는 가장 좋은 방법은 htmlspecialchars()를 사용하는 것
{% endhint %}

{% hint style="warning" %}
또는 입력하는 문자열의 길이를 제한하는 것 또한 좋은 방법이 될 것이다.
{% endhint %}


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