picoCTF Learning Guides

Topics:

General Skills
Cryptography
Web Exploitation
Forensics
Binary Exploitation
Reversing

General Skills

Learn to use SSH and Netcat.
Learn about number systems such as Decimal (base-10), Binary (base-2), Octal (base-8) and Hexadecimal (base-16).
Big Endian - big end first; the most significant byte is stored at the smallest memory location; commonly used in networking.
Little Endian - little end first; least significant byte stored at the smallest memory address; used in processors.

Cryptography

Examples of ciphers include Caesar cipher, Affine cipher, Vignere cipher and Hill cipher.
Authentication - refers to authenticity of message; to confirm if the message is from a particular user.
Encryption - encoding a message so only a particular user can read it.
Use tools such as hashcat and John the Ripper for password cracking.

Web Exploitation

We can understand the website code by viewing the page source and using Developer Tools.
SQLi (SQL Injection) - injection attack where an attacker can execute SQL commands and control a web app's database server.

Forensics

Metadata - data about file itself like length, time created, author, etc.
File carving - technique to extract data from a disk drive without having the normal file system to easily recover files.
When a file gets deleted, the data does not get deleted but just the reference to that data.

Binary Exploitation

GDB (GNU Project Debugger) - software for debugging.
GDB contains two major parts - the symbol side (the program) and the target side (the manipulations done to program).
gcc -g filename.c -o executablename to compile the code in C, gdb executablename to start debugging.

Reversing

To understand reversing, we need to have a basic idea of programming languages such as C, Assembly, and Python.