Before we start to develop games, we need to downloading and installing Unity and Visual Studio. To install these softwares, we need to follow the steps,

• go to the download page of Unity, click to Download Unity Hub
• double click on the UnityHubSetup file we download
• agree to all terms of services and install the Unity Hub
• open Unity hub and click the “Installs” tab along the left side and click to Add a new Unity version
• we should select 2020.3.X LTS (commonly Recommend Release) and then click next. …

1. Introduction to Stack Overflow

In this section, we will talk about the most popular and critical type of vulnerability called stack overflow. Techniques to exploit stack overflow problems were first documented in a well-known Phrack article called Smashing The Stack For Fun And Profit by Aleph One. Let’s first see some basic definitions in this article.

(1) Buffer

A buffer is simply a contiguous block of computer memory that holds multiple instances of the same data type.

(2) Static Arrays and Dynamic Arrays

Arrays, like all variables in C, can be declared either static or dynamic. Static variables are allocated…

1. Linux Shells

Let’s discuss today’s main topic about writing the shellcode. Shellcode often means a generic payload for the exploitation, so its goal is to launch an interactive shell as a result. First, we have to direct to the tut02-shellcode directory by,

$ seclab tut02
$ cd ~/tuts/lab02/tut02-shellcode/
$ ls -al
total 44
drwxrwxr-x 2 vagrant vagrant  4096 May 10 09:57 .
drwxrwxr-x 3 vagrant vagrant  4096 May  6 03:25 ..
-rw-r--r-- 1 vagrant vagrant   535 May  9 21:54 Makefile
-rw-r--r-- 1 vagrant vagrant 11253 May  9 21:54 README
-rw-r--r-- 1 vagrant vagrant  1090 May  9 21:54 shellcode.S …

1. Ghidra

One of the static analysis tools that we can use for disassembling code is called Ghidra. Ghidra is a free and open-source reverse engineering tool developed by the National Security Agency of the United States of America.

First, let’s download this file from the official website of Ghidra,

$ cd ~/cs6265-tut/
$ curl https://ghidra-sre.org/ghidra_9.2.3_PUBLIC_20210325.zip > ghidra_9.2.3_PUBLIC_20210325.zip

Then, let’s unzip the file and change it to this directory,

$ unzip ghidra_9.2.3_PUBLIC_20210325.zip
$ cd ghidra_9.2.3_PUBLIC

In this directory, we can change the mode of the file ghidraRun to 777 and then execute this file,

$ chmod 777 ghidraRun
$ ./ghidraRun

After…

1. GDB

In the previous section, we have discussed the GNU debugger and PWN debugger. Now, let’s summarize the basic usage of them.

• Initiate debugging

$ gdb <filename>

• Set breakpoint at a specific location (e.g. main)

(gdb) b main

• Run the debugged program

(gdb) r

• Check the register values

(gdb) i r

• Examine (briefly, x) the memory contents of an instruction

(gdb) x/1i 0x80492c9

• Examine (briefly, x) the memory contents of one instruction and its next 9 instructions

(gdb) x/10i 0x80492c9

• Examine (briefly, x) the memory contents of a string

(gdb) x/1s 0x80492c9

• Show the value of a specific register by…

<somthing may be wrong with the picture>

If you are not a registered student, you can simply skip this section because the resource in this part will be private. If you are a registered student, follow the steps before taking the first lab assignment.

• Step 1. Register your account and receive an api-key here (note that this address changes every year and you need to go to the official website to get the latest one).
• Step 2. Log in with your api-key in the email.
• Step 3. ssh connect to the server for a particular lab with the information provided…

1. Basic Setups

Let’s now play with a binary. In this lab, we have 4 binary files. Before you check these files, you have to make sure that you are in the VM environment.

$ vagrant ssh
$ seclab tut01

We can check these files by,

$ cd ~/tuts/lab01/tut01-crackme
$ ls
README  crackme0x00  crackme0x01  crackme0x02  crackme0x03

What are these files? Let’s try the first one crackme0x00 as an example. Suppose we run this executable file and enter the password 1234, we can not access it because the password is not correct.

$ ./crackme0x00
IOLI Crackme Level 0x00
Password: 1234
Invalid Password!

…

1. Parts of the Guitar

• Body: the main part of the guitar
• Soundboard: the top piece of wood on the body
• Soundhole: the round part on the middle of the body
• Rosette: the decorated part along the edge of the soundhole.
• Bridge: the wood used to connect the strings to the soundboard
• Saddle: means a small piece of hard material like a piece of bone that supports the strings on the bridge
• Strings: means the vibrating elements that produce sound
• Neck: the board where we put our left-hand fingers
• Fretboard: on top of the neck, traditionally made by rosewood or maple
• …