### Solution
* When we check at `robots.txt` we find `sitemap.xml`
* When looked at `sitemap.xml` we get
> <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>https://wk.hexionteam.com/404.html</loc>
</url>
<url>
<loc>https://wk.hexionteam.com/robots.txt</loc>
</url>
<url>
<loc>https://wk.hexionteam.com/.well-known/security.txt</loc>
</url>
</urlset>
* Go to [https://wk.hexionteam.com/.well-known/security.txt](http://wk.hexionteam.com/.well-known/security.txt) , we get the flag.

> **Flag:**`hexCTF{th4nk_y0u_liv3_0v3rfl0w}`