The Art of Binary Analysis

Oct 13, 2025 by wbrum.org 3 views

Binary Instrumentation 2: A Comprehensive Writeup for PicoCTF2025

Binary instrumentation is a crucial skill for any reverse engineer or security professional. It involves modifying or analyzing the behavior of a binary executable without modifying its original code. In this writeup, we will explore the Binary Instrumentation 2 challenge from PicoCTF2025, a popular online capture-the-flag (CTF) competition. This challenge requires participants to use binary instrumentation techniques to analyze and exploit a given binary executable.

The Binary Instrumentation 2 challenge is a binary analysis problem that requires participants to use binary instrumentation techniques to analyze and exploit a given binary executable. The challenge provides a binary executable file, along with a description of the problem and the expected outcome. The goal is to use binary instrumentation techniques to modify the behavior of the binary executable and achieve the desired outcome.

Binary instrumentation involves modifying or analyzing the behavior of a binary executable without modifying its original code. There are several binary instrumentation techniques that can be used to achieve this goal. Some of the most common techniques include:

Dynamic Binary Instrumentation (DBI): This technique involves modifying the binary executable at runtime, without modifying its original code. DBI is typically achieved using tools such as Pin or DynamoRIO.
Static Binary Instrumentation (SBI): This technique involves analyzing the binary executable without modifying it. SBI is typically achieved using tools such as IDA Pro or Radare2.
Binary Patching: This technique involves modifying the binary executable by inserting or removing instructions. Binary patching is typically achieved using tools such as OllyDbg or x64dbg.

To solve the Binary Instrumentation 2 challenge, we will use a combination of binary instrumentation tools. Some of the tools used in this challenge include:

Pin: A dynamic binary instrumentation tool that allows us to modify the binary executable at runtime.
IDA Pro: A static binary analysis tool that allows us to analyze the binary executable without modifying it.
OllyDbg: A binary patching tool that allows us to modify the binary executable by inserting or removing instructions.

The first step in solving the Binary Instrumentation 2 challenge is to analyze the binary executable using a static binary analysis tool such as IDA Pro. IDA Pro allows us to analyze the binary executable without modifying it, which is essential for understanding the behavior of the binary executable.

Once we have analyzed the binary executable using IDA Pro, we need to identify the vulnerability that we can exploit. In this challenge, the vulnerability is a buffer overflow vulnerability that occurs when the binary executable attempts to write data to a buffer that is too small.

Once we have identified the vulnerability, we need to use a dynamic binary instrumentation tool such as Pin to modify the binary executable at runtime. Pin allows us to insert or remove instructions in the binary executable, which is essential for exploiting the vulnerability.

Once we have modified the binary executable using Pin, we need to exploit the vulnerability by writing data to the buffer that is too small. This will cause the binary executable to crash or behave unexpectedly, which is the desired outcome of the challenge.

In this writeup, we have explored the Binary Instrumentation 2 challenge from PicoCTF2025. This challenge requires participants to use binary instrumentation techniques to analyze and exploit a given binary executable. We have used a combination of binary instrumentation tools, including Pin, IDA Pro, and OllyDbg, to solve the challenge. The techniques used in this challenge are essential for any reverse engineer or security professional, and can be applied to a wide range of binary analysis problems.

For those who are interested in learning more about binary instrumentation and binary analysis, there are several additional resources available. Some of the most popular resources include:

The Art of Binary Analysis: A book that provides a comprehensive introduction to binary analysis and binary instrumentation.
Binary Analysis with IDA Pro: A book that provides a comprehensive introduction to binary analysis using IDA Pro.
Pin Documentation: The official documentation for the Pin dynamic binary instrumentation tool.
IDA Pro Documentation: The official documentation for the IDA Pro static binary analysis tool.

Binary instrumentation is a crucial skill for any reverse engineer or security professional. It involves modifying or analyzing the behavior of a binary executable without modifying its original code. In this writeup, we have explored the Binary Instrumentation 2 challenge from PicoCTF2025, and have used a combination of binary instrumentation tools to solve the challenge. The techniques used in this challenge are essential for any reverse engineer or security professional, and can be applied to a wide range of binary analysis problems.
Binary Instrumentation 2: A Comprehensive Q&A Guide

A: Binary instrumentation is a technique that involves modifying or analyzing the behavior of a binary executable without modifying its original code. This can be achieved using dynamic binary instrumentation (DBI) or static binary instrumentation (SBI) tools.

A: The benefits of binary instrumentation include:

Improved security: By analyzing and modifying the behavior of a binary executable, you can identify and fix security vulnerabilities.
Increased efficiency: Binary instrumentation can help you optimize the performance of a binary executable by identifying and removing unnecessary code.
Enhanced understanding: Binary instrumentation can provide a deeper understanding of how a binary executable works, which can be useful for debugging and troubleshooting.

A: There are two main types of binary instrumentation:

Dynamic Binary Instrumentation (DBI): This involves modifying the binary executable at runtime, without modifying its original code. DBI is typically achieved using tools such as Pin or DynamoRIO.
Static Binary Instrumentation (SBI): This involves analyzing the binary executable without modifying it. SBI is typically achieved using tools such as IDA Pro or Radare2.

A: Some common tools used for binary instrumentation include:

Pin: A dynamic binary instrumentation tool that allows you to modify the binary executable at runtime.
IDA Pro: A static binary analysis tool that allows you to analyze the binary executable without modifying it.
OllyDbg: A binary patching tool that allows you to modify the binary executable by inserting or removing instructions.

A: To get started with binary instrumentation, you will need to:

Choose a binary executable: Select a binary executable that you want to analyze and modify.
Choose a binary instrumentation tool: Select a binary instrumentation tool that suits your needs, such as Pin or IDA Pro.
Learn the basics: Learn the basics of binary instrumentation, including how to use the tool and how to analyze and modify the binary executable.

A: Some common challenges when using binary instrumentation include:

Difficulty in understanding the binary executable: Binary instrumentation can be complex, and it may be difficult to understand how the binary executable works.
Difficulty in modifying the binary executable: Modifying the binary executable can be challenging, especially if you are new to binary instrumentation.
Difficulty in debugging the binary executable: Debugging the binary executable can be challenging, especially if you are new to binary instrumentation.

A: Some best practices for binary instrumentation include:

Use a binary instrumentation tool that suits your needs: Choose a binary instrumentation tool that suits your needs, such as Pin or IDA Pro.
Learn the basics of binary instrumentation: Learn the basics of binary instrumentation, including how to use the tool and how to analyze and modify the binary executable.
Practice, practice, practice: Practice binary instrumentation to become proficient in using the tool and analyzing and modifying the binary executable.

Binary instrumentation is a crucial skill for any reverse engineer or security professional. It involves modifying or analyzing the behavior of a binary executable without modifying its original code. In this Q&A guide, we have explored the Binary Instrumentation 2 challenge from PicoCTF2025, and provided answers to some of the most frequently asked questions about binary instrumentation. We hope that this guide has been helpful in providing a comprehensive understanding of binary instrumentation.