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Posts tagged with "reverse-engineering"

Investigating a Backdoor.SH.SHELLBOT.AA Infection

January 22, 2020 ❖ Tags: writeup, reverse-engineering, linux, security

It's typical for the younger sibling to look up to and mimic the older sibling, which is apparently what happened while I was away at school. I'm self-hosting a few services off of a Raspberry Pi B+ back at my parents' house, and when my brother got a Pi of his own, he decided that he also wanted to use it for self-hosting. Unfortunately, he doesn't know much about security, and unintentionally did me the favor of setting up a honeypot.

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Browser Games Aren't an Easy Target

January 10, 2020 ❖ Tags: writeup, programming, reverse-engineering, video-games, game-hacking, javascript

If you're about my age and had a similarly dull upbringing, you probably also have memories of playing video games behind a teacher's back whenever class involved going to some sort of "computer lab." Flash games were the thing when I was in elementary school, and when I was in middle school, I'd bring Quake with me on a flash drive. By the time I was in high school, I'd realized that these opportunities were better spent getting a head start on homework for other classes, but I did have a few friends who still passed the time playing video games. Rather than Flash games or Quake, though, these were browser games using the new-fangled HTML5 canvas. I'd practically forgotten these games existed until someone from my capture-the-flag team mentioned "krunker.io". Apparently it's one of the more popular ones. It got me thinking about how I'd go about writing cheats for a game in the browser. Writing cheats for CS:GO was a breeze, so why would this be any harder? I had some time to spare over winter break, so I decided to give it a go and see what kind of damage I could do.

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Writeups for Dennis Yurichev's Reverse Engineering Challenges (#36-#74)

December 29, 2019 ❖ Tags: writeup, reverse-engineering, x86

This is the fourth and final set of for my self-imposed challenge of completing at least fifty of the exercises on Dennis Yurichev's challenges.re by the end of the year. The previous set is available here.

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Writeups for Dennis Yurichev's Reverse Engineering Challenges (#23-#35)

August 18, 2019 ❖ Tags: writeup, reverse-engineering, x86

This is the third set of solutions for my self-imposed challenge of completing at least fifty of the exercises on Dennis Yurichev's challenges.re by the end of the year. The previous set is available here.

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Writeups for Dennis Yurichev's Reverse Engineering Challenges (#12-#22)

May 28, 2019 ❖ Tags: writeup, reverse-engineering, x86

This is the second set of solutions for my self-imposed challenge of completing at least fifty of the exercises on Dennis Yurichev's challenges.re by the end of the year. The first set is available here.

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Writeups for PlaidCTF 2019

April 14, 2019 ❖ Tags: writeup, security, reverse-engineering, capture-the-flag, x86, c, python

My long-lived hiatus from capture-the-flag has come to an end, as I got off my ass this weekend to play in PlaidCTF 2019. Being a one-man team is pretty lonely, but my old team wasn't playing, and even if they were, I don't know if I would've wanted to make the commute just to play with them.

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Writeups for Dennis Yurichev's Reverse Engineering Challenges (#2-#11)

March 10, 2019 ❖ Tags: writeup, reverse-engineering, arm, x86

As mentioned in the (now deleted) post I wrote describing my plans for 2019, one of my goals this year is to get through at least 50 of the exercises on Dennis Yurichev's challenges.re. I've decided to document my progress in the form of writeups for the challenges I complete, batched in sets of ten exercises. For each challenge, I'll try to explain the intuitions that brought me closer to answering the recurring question from Yurichev, "[w]hat does this code do?"

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Reverse Engineering By Hand

March 01, 2018 ❖ Tags: tutorial, reverse-engineering, x86, c, linux

My capture-the-flag team played in the Insomni'hack teaser this year. During the competition, I worked on a single challenge titled "sapeloshop." It was labeled as "Medium-Hard," and it was in the binary exploitation category. The source code for the server wasn't provided, so reverse engineering was necessary. I don't think that having to reverse the binary was supposed to be the hard part, as most of the behavior could have been inferred through some high-level analysis, yet I spent nearly five hours fruitlessly trying to reverse it, and the subsequent burnout was bad enough that I went home early. This wasn't the first time a reversing task had gotten the best of me; there had been a few competitions last year where I felt a similar loss in motivation. Noticing this recurring pattern frustrated me, and that frustration drove me to think about ways to improve myself as a reverse engineer.

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Understand Game Hacking In One Post

September 05, 2017 ❖ Tags: tutorial, reverse-engineering, video-games, game-hacking, x86, c++, radare2

At a first glance, it might seem that game cheats like AimTux are something that could only be conjured by the most talented of reverse engineers. That was at least my initial view on it, especially since I always saw these game hackers using outlandish terms that I hadn't heard in over a year of playing in CTF's. Don't be fooled; game hacking isn't nearly as complex as its community makes it seem. In this post, I will explain the concepts in a way that is familiar to people with experience in binary exploitation and reverse engineering, but it shouldn't be too hard to understand if you lack that background.

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Game Hacking on Linux - scanmem Basics

June 18, 2017 ↻ Crosspost ❖ Tags: tutorial, reverse-engineering, linux, video-games, game-hacking

Hey, this is a very brief tutorial on scanmem, a memory manipulation tool for Linux that’s well suited to game hacking. I’ll be using GZDoom as an example, but you should be able to follow along with any game you want.

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