Simple One

This is a writeup of the web challenge Simple one from the Security Valley CTF

Level: 1, Score: 5

Premise

Our administrators have forgotten a file on our web server. This file is very important for us. Unfortunately, our admin also forgot the location of the file. Can you find this file?

Link: https://pwnme.org/

Challenge links:

https://pwnme.org/

Observations

We navigate to the site, and at first glance, it looks like little more than a static page. Viewing the source doesn’t yield many results either. Viewing the source files, we find 3 js files, main, polyfills and runtime, but searching for anything such as flag or SecVal give no useful results. The main.js files main purpouse seems to be rendering the site.

Solution

Since we don’t have any input fields to try our luck in, we can take another approach; attacking the web server itself. We can start by attempting to enumerate the server with a tool like dirbuster. Running this tool with the built in kali wordlist located at /usr/share/wordlists/dirb/common.txt and the following settings: . After running for a while, we find one file that stands out when viewing our results, seen here: This file stands out for two reasons: it has a 200 status code, and its size is indicating something different from other files found by the scanner (since most other files had a status code of 502 and size of 384 and 377).

If we navigate to our newly discovered page, we find the following contents:

Which gives us our flag.

Tools used:

• dirbuster
• the file: /usr/share/wordlists/dirb/common.txt found in a default kali install