When the world becomes a game, and every piece of data is a potential flag, you know you’re in a hacker’s playground. Let’s walk through the strategy and steps I took to conquer this CTF challenge.
Step 1: Scanning the Target
The very first step in any CTF challenge is to gather information about the target. This is known as reconnaissance or information gathering. I used Nmap, one of the most powerful tools for scanning networks, to find open ports on the target system. The command I used was: nmap –A target-IP
The output showed three open ports:
- Port
21 (FTP): A file transfer service. - Port
22 (SSH): A secure shell for remote
login. - Port
80 (HTTP): A web service.
Open ports represent potential entry points into the system.
We need to focus on these services because they might be vulnerable or
misconfigured, allowing us to gain access.
After analyzing the ports, I decided to start with Port
21, the FTP service. FTP is commonly used for file transfer, and
sometimes, misconfigurations or weak credentials can expose sensitive
information.
Step
2: Accessing the FTP Server
I
connected to the FTP service using the following command: ftp target-IP
· The ftp
command is used to establish a connection to the FTP server at the given IP
address.
· I was prompted to
provide a username. Surprisingly, the system accepted Anonymous, which
allowed unauthenticated access.
The
fact that Anonymous access was allowed
means there might be files on the system that anyone can read, including
potential clues. Misconfigured FTP servers often allow unauthenticated access,
which can be exploited.
Next,
I ran the command: ls –la
Thels -la command lists all
files in the directory with detailed information, including hidden files. This
helped me identify any potentially interesting files in the FTP server’s root
directory.
The
directory revealed two text files: locks.txt and
task.txt. These files could contain
crucial information to help me advance in the CTF.
Step 3: Inspecting the Files
I decided to open both files and see what information they contained. First,
I opened locks.txt, then moved to task.txt.
· The files were
simple text files, but in a CTF, even a small hint can be incredibly valuable.
· In task.txt,
I found a username: lin. This was a critical piece of information. lin
was likely the user account that I needed to target in the next step.
The
username lin pointed me to the next
stage: gaining access to the lin user’s
account, which would likely bring me closer to the flag.
