Intro to CTFs

3 min read

Finding CTFs

One of my favorite websites for viewing and signing up for upcoming CTFs is CTFtime.

It shows you:

  • Event difficulty
  • Format and categories included
  • Duration (from a couple of hours to a couple of days)
  • Rank weighting (where the higher the difficulty and weighting, the more competitive the CTF is)

You don’t have to make an account on there immediately, but you can easily view upcoming CTFs at CTFtime Upcoming Events.

Basic Tools for CTFs

As per usual, I highly recommend using Kali Linux as it comes preinstalled with many tools you may need.

Because these tools can be overwhelming, I would really encourage signing up for picoCTF. They host all their past CTF challenges on there, allowing you to easily sort by category and track your progress (links at the bottom).

Pwn / Binary Exploitation

  • pwntools: A Python library essential for writing clean exploit scripts
  • ROPgadget: Automatically searches binaries to find gadgets for building ROP chains
  • checksec: Audits security mitigations (Canary, NX, PIE, RELRO) on binaries
  • gdb + gef / peda / pwndbg: Debuggers and plugins designed for vulnerability analysis and exploit development

Reverse Engineering (Rev)

  • Ghidra: Free, open-source software reverse engineering suite and disassembler developed by the NSA
  • radare2: Highly configurable, scriptable command-line reverse engineering framework
  • Binary Ninja: Clean, user-friendly disassembler and decompiler with an interactive interface and API

Most tools for Pwn / Binary Exploitation also apply to Rev—there is significant overlap between the two categories.

Web Exploitation

  • Burp Suite: Industry-standard web application security testing and traffic interception proxy
  • SQLmap: Automated tool for detecting and exploiting SQL injection flaws
  • ffuf: Fast web fuzzer for discovering hidden endpoints, files, and parameters
  • Gobuster: High-speed directory and DNS brute-forcing tool
  • cURL: Command-line utility to craft HTTP requests, test APIs, and inspect raw server responses

Cryptography (Crypto)

  • CyberChef: Swiss army knife for decoding, decompressing, and transforming data
  • Hashcat: Advanced GPU-accelerated password and hash cracking utility
  • John the Ripper: Fast and versatile password hash cracker
  • xortool: Utility for analyzing multi-byte XOR ciphers
  • SageMath: Open-source mathematics system for solving complex algebraic crypto challenges

Forensics

  • binwalk: Analyzes, reverse engineers, and extracts embedded firmware images and hidden files
  • foremost: File carving tool based on headers, footers, and internal data structures
  • exiftool: Reads, writes, and manipulates image/document metadata
  • stegsolve: Java-based tool for analyzing image-based steganography planes
  • Volatility: Memory forensics framework for incident response and memory dump analysis
  • Wireshark: Interactive GUI network packet capture and protocol analyzer

Kali includes many additional forensic utilities pre-installed, such as pdfid.

Misc (Useful for Any Challenge)

  • strings: Extracts readable ASCII/Unicode text sequences from binaries or arbitrary files
  • xxd / hexdump: Command-line hex viewing and editing tools
  • tcpdump: Lightweight command-line packet capture utility

Don’t forget built-in manual pages and help flags: man <tool_name> or <tool_name> --help.

Important Links & Resources

Graph View