Challenge list

03. Linux First Steps - Find the File

You've connected to a Linux server! There's a file with the flag in the home directory. Use basic commands to find the…

04. Find the Hidden File

In Linux, files whose names start with "." (dot) are "hidden files" and are not displayed with the regular ls command.…

05. HTML Source Code Secret

Web pages contain a lot of information that isn't visible on the surface. Looking at HTML source code, you can often…

06. JavaScript Password Check

This page has a password-protected area. However, because the password check is done in JavaScript, you can find the…

07. Peek at Cookies

Websites use a mechanism called cookies to store information in your browser. They're used for managing login states,…

Network SecurityLevel 1★☆☆☆☆

08. Network Basics - Learn Port Numbers

Networks use port numbers to identify services. For example, a web server (HTTP) usually uses port 80, and encrypted…

10 ptsOpen challenge

ProgrammingLevel 1★☆☆☆☆

09. Python Automation - File Reading

In security work, programming is essential for processing large amounts of data. In this challenge, you'll use Python…

General SkillsLevel 1★☆☆☆☆

10. Security Basics - Ethics and Rules

To become a white hat hacker, knowledge of ethics and laws is just as important as technical skills. In this…

Linux-01. Grep the Needle Out of the Log Pile

Under /var/log/app there are many date-stamped log files, and the flag is hidden in a single ERROR line among them.…

Linux-SSH Key Hunt. Discovering a Hidden Private Key File

A file resembling a private key is hidden deep inside an application's configuration directory. Use find to track it…

Linux-Archive. Extracting a Secret from a Tarball

A compressed archive (.tar.gz) in the home directory contains a file with the flag hidden inside. Extract it with tar…

Linux-Custom. Inspecting a Scheduled Backup Script

Inspect the scheduled script placed under /usr/local/bin along with the cron entry that registers it. Comments inside…

Linux-Service Config. Digging into Nginx Configuration Files

Several service configuration files exist under /etc. Some are decoys while others hold real clues, so read through…

Linux-Symlink Basics. Following a Chain of Links to the End

A single chain of symbolic links connects several files. Follow the chain with ls or readlink until you reach the real…

Linux-Disk Usage. Tracking Down a Bloated File

A hidden directory contains an unusually large file. Use du or find's size options to track it down and inspect its…

Linux-Permissions Basics. Running a Script with No Execute Bit

A script file lacks execute permission. Check its permissions, add execute permission with chmod, and then run it.

Linux-File Type Disguise. Unmasking Files with the file Command

A file with a .jpg extension may actually contain plain text. Use the file command to spot files whose extension does…

Linux-Process Basics. Checking a sleep Command's Arguments

Find the process with the target command-line argument among several processes running in the background. This…

Linux-Deep Search. Discovering a Deeply Nested File

A single file containing the flag is hidden deep inside many nested directories. Use the find command to locate the…

Linux-Environment Variable Basics. Checking Shell Startup Variables

One of the environment variables set when the shell starts holds the flag. Check it with the env command or echo…

Linux Basics - Permissions and SUID

Learn basic Linux commands and file permissions. Use hints to find SUID and retrieve the flag.

30 ptsOpen challenge

SQL Injection 101

This login form has an SQL Injection vulnerability. Log in as admin without proper credentials and retrieve the flag.

45 ptsOpen challenge

Web-04. The robots.txt Trap

Websites often serve a robots.txt file for crawlers. In this challenge, check whether a file that robots.txt tells…