Challenge list
Linux-Symlink Maze. Navigating a Branching Path
Several directories are connected in a tangled web of symbolic links. Without being misled by decoy hint files, follow…
Linux-Script Debug. Fixing a Broken Bash Script
This script has several intentional bugs (typos, syntax mistakes) and fails to run to completion. Use bash's debugging…
Linux-Network Basics. Connecting to a Listening Port
A background service on this system is listening on a specific port. Identify the port with ss/netstat and connect to…
Linux-Backup Finder. Spotting the Real Temp File
The project directory contains several decoy backup/temp files ending in .bak, .tmp, or ~. The real flag is hidden…
Linux-Pipeline. Narrowing Down Logs with grep and awk
The access log contains many entries. One IP address generated a burst of 404s, and stitching together the paths of…
Linux-Package Info. Inspecting Installed Package Details
A custom-built deb package is installed on this system. Use dpkg or apt to inspect the package's details and find…
Linux-Process Hunting. Tracking Down a Running Process
Among several background processes, one has the flag embedded in its command-line arguments. List them with ps and…
Linux-User Investigation. Filtering the Target User with awk
Several users are registered on this system. Parse /etc/passwd with awk to find the one matching a specific condition,…
Linux-Log Rotation. Searching Compressed Historical Logs
Some older log files have been gzip-compressed by log rotation. Use a command that searches inside compressed files…
Linux-Log Explorer. Digging the Flag Out of Multiple Logs
Multiple application and system log files are provided. The flag is embedded in a single DEBUG-level line — narrow it…
Linux-Environment Secrets. Finding the Variable Named FLAG
Several environment variables, including some dummy credentials, are set on this system. List them with env and find…
OSINT Basics - Metadata Analysis
Files recovered from a departed employee's shared drive (photos `IMG_*.jpg` and Office documents) are in…
Hidden PDF Streams
The PDF file contains compressed object streams. An internal note that is not shown on the page is hidden inside them.…
Python Practice - Bulk Base64 Stream Decoding
Every line of data.txt (about 150 lines, created at every start) is Base64. Decode line by line; when the result…
Python Practice - Conditional CSV Sales Filtering
data.txt, created at every start, is a sales CSV (transaction_id,date,product_id,amount,status,ref,notes). Several…
Python Practice - Compound JSON User Query
Examine the JSON data.txt ({"users": [...]}) created at every start. Each user has id, name, email, role, active and…
Python Practice - Target-IP Access Log Tracing
data.txt (about 1,300 lines, created at every start) is a web server access log. Extract only the requests from…
Python Automation - Bulk Base64 Decoding
Every line of data.txt (about 150 lines, created at every start) is Base64. Decode line by line; when the result…
Python Automation - CSV Sales Filtering
data.txt, created at every start, is a sales CSV (transaction_id,date,product_id,amount,status,ref,notes). Several…
Python Automation - JSON User Query
Examine the JSON data.txt ({"users": [...]}) created at every start. Each user has id, name, email, role, active and…
Python Automation - Access Log Parsing
data.txt (about 1,300 lines, created at every start) is a web server access log. Extract only the requests from…
Python Automation - Password Hash Cracking
Examine data.txt (a list of SHA-256 digests) and wordlist.txt (800 four-character lowercase alphanumeric tokens), both…
RC4 Stream Cipher Weakness
RC4 was once widely used but is now deprecated. This introductory task focuses on recognizing the provided data…
Vigenere Cipher Decryption
Decrypt a Vigenere cipher when the key length is known and retrieve the flag. Ciphertext:…