Practical Binary Analysis – CTF Walkthrough – Level 3, 4

Hello, In this article I’ll present you my solution on the Chapter 5 CTF from the book Practical Binary Analysis. For this binary, the hint is to fix four broken things. Running file gives us the following response: 1 2 binary@binary-VirtualBox:~/ctf$ file ./lvl3 ./lvl3: ERROR: ELF 64-bit LSB executable, Motorola Coldfire, version 1 (Novell Modesto) error reading (Invalid argument) And the readelf command gives us: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 binary@binary-VirtualBox:~/ctf$ readelf -h ./lvl3 ELF Header: Magic: 7f 45 4c 46 02 01 01 0b 00 00 00 00 00 00 00 00 Class: ELF64 Data: 2's complement, little endian Version: 1 (current) OS/ABI: Novell - Modesto ABI Version: 0 Type: EXEC (Executable file) Machine: Motorola Coldfire Version: 0x1 Entry point address: 0x4005d0 Start of program headers: 4022250974 (bytes into file) Start of section headers: 4480 (bytes into file) Flags: 0x0 Size of this header: 64 (bytes) Size of program headers: 56 (bytes) Number of program headers: 9 Size of section headers: 64 (bytes) Number of section headers: 29 Section header string table index: 28 readelf: Error: Reading 0x1f8 bytes extends past end of file for program headers At this moment, it was clear that the ELF header is broken, in order to fix it I opened up Wikipedia and the elf specification. ...

September 19, 2019 · 3 min · Denis Nuțiu

Introduction to Angr

I always wanted to play around with a binary analysis framework but most of the time I was turned off by how difficult it was to install and use it. Just recently I’ve thought to give angr a try and now I want to share my experience with you! I will present you a two scripts that solve two challenges, if you wish to dig deeper and learn Angr then you should visit it’s official documentation. ...

August 21, 2019 · 5 min · Denis Nuțiu

Practical Binary Analysis | No Starch Press

I started reading this book in november and it took me about two weeks to finish it. You should be a bit comfortable Linux and programming if you plan to give it a try. Here are my thoughts about it. What I like the most about this book is that it explains the subject in a straightforward and concise way! The author is a very knowledgeable security researcher and his work is state of the art! ...

December 12, 2018 · 2 min · Denis Nuțiu

Practical Binary Analysis – Crackme Walkthrough – Level 2

I’ve recently finished reading a book called Practical Binary Analysis which I consider a state of the art book (review will come soon) and I would like to post my solution to the crackme found in chapter 5. 1. A New CTF ChallengeComplete the new CTF challenge unlocked by the oracle program!You can complete the entire challenge using only the tools discussedin this chapter and what you learned in Chapter 2. After completingthe challenge, don’t forget to give the flag you found to the oracle tounlock the next challenge ...

December 2, 2018 · 6 min · Denis Nuțiu