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Assembler *

Low-level programming language in which there is a very strong correspondence between the program's statements and the architecture's machine code instructions

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On the difference between regular functions and Lambdas

Level of difficulty Medium
Reading time 11 min
Views 2K

The point of this article is to explore Lambda functions, their dirrerences from regular functions and how they are implemented, based on C++, Python and Java programming languages.

Throughout this article I will be using godbolt.org to compile code and see machine code or byte code.

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Total votes 2: ↑2 and ↓0 +2
Comments 2

Music on the Commodore PET and the Faulty Robots

Reading time 26 min
Views 2.5K

After completion of the System Beeps, I wasn’t planning to make another stand alone album release with the pseudo polyphonic music, as I felt the topic had been explored enough. This, however, wouldn’t mean I couldn’t apply the experience and skills gained to make more utilitarian stuff, like an actual retro game OST or an old school demoscene project. Such an opportunity arose in Autumn 2020, as David Murray of The 8-bit Guy Youtube channel fame announced his new game to be in development, the Attack of The PETSCII Robots for Commodore PET and some other Commodore 8-bitters. As I previously worked with David on his previous big release, Planet X3 game for MS-DOS, and this was a perfect opportunity to satisfy my interest towards the pre-graphics era PCs as well as apply my vast experience both in the minimalistic computer music and 6502 assembly programming, I offered my services that had been accepted. Besides the sound code I also had hopes to participate as a music composer this time.

Unfortunately, this time the project didn’t went well on my side, and lots of issues of all kinds eventually turned it into a small scale development hell (you can learn more from a series of posts at my Patreon blog)  The end result was that my code and sound effects were only used in the VIC-20 port, and music for other versions has been created by other people. However, I was left with the full working code of the sound system for PET, and a number of music sketches. It would be a pity to file it into the archive, PET projects aren’t a frequent thing these days, so another chance to use the stuff wouldn’t come any time soon. So I got the idea to develop my music sketches into full songs, and release it as an alternative OST, and having David’s approval it has been done and released in the Winter 2021 as Faulty Robots, a small music album for PET that is available as a digital audio release and a runnable program for the actual PET computer.

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Total votes 5: ↑5 and ↓0 +5
Comments 2

Let’s deal with WeChat — the second most popular messenger in the world

Reading time 5 min
Views 2K

  • A short excursion into WeChat;
  • About the platform, the version of the application, the utilities used and the decryption of the executable file;
  • • About two protocols (old one and new one);
  • About serialization of objects;
  • Used cryptography and key exchange;
  • About headers and hash-functions;
  • About the exposures found.

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Total votes 5: ↑5 and ↓0 +5
Comments 1

Full motion video with digital audio on the classic 8-bit game console

Reading time 13 min
Views 1.3K

Back in 2016 an United States based music composer and performer Sergio Elisondo released an one-man band music album A Winner Is You (know your meme), with multi-instrumental cover versions of tunes from numerous memorable classic NES games. A special feature of this release has been its version released in the NES cartridge format that would run on a classic unmodified console and play digitized audio of the full album, instead of the typical chiptune sound you would expect to come from this humble console. I was involved with the software development part of this project.

This year Sergio makes a return with a brand new music release. This time it is all original music album You Are Error, heavily influenced with the video game music aesthetics. It also comes with a special extra. This time we have raised the stakes, and a new NES cartridge release includes not only the digitized audio, but full motion videos for each song, done in the silhouette cutout style similar to the famous Bad Apple video. Yet again, this project is crowdfunded via Kickstarter. It already got the asked amount in a mere 7 hours, but there is still a little time to jump on the bandwagon and get yourself a copy. In the meantime I would like to share an insight on the technical side of both projects.

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Total votes 4: ↑4 and ↓0 +4
Comments 0

SLAE — SecurityTube Linux Assembly Exam

Reading time 17 min
Views 2.4K
SecurityTube Linux Assembly Exam (SLAE) — is a final part of course:
This course focuses on teaching the basics of 32-bit assembly language for the Intel Architecture (IA-32) family of processors on the Linux platform and applying it to Infosec and can be useful for security engineers, penetrations testers and everyone who wants to understand how to write simple shellcodes.
This blog post have been created for completing requirements of the Security Tube Linux Assembly Expert certification.
Exam consists of 7 tasks:
1. TCP Bind Shell
2. Reverse TCP Shell
3. Egghunter
4. Custom encoder
5. Analysis of 3 msfvenom generated shellcodes with GDB/ndisasm/libemu
6. Modifying 3 shellcodes from shell-storm
7. Creating custom encryptor
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Total votes 4: ↑2 and ↓2 0
Comments 0

Making a demo for an old phone — AONDEMO

Reading time 13 min
Views 3.5K
I wanted to make a demo ever since I saw the classic Polish mega demo Lyra II for first time in 1997. I also wanted to do something for the largest Russian demo party Chaos Constructions for a long while, but have never gotten around that, being occupied with other duties. Finally, in 2018 the time has come, and I fulfilled both desires at once, Van Damm's double impact style — made a demo called AONDEMO that entered ZX Spectrum 640K Demo compo at Chaos Constructions.

I bet the red thing you've just seen does not look much a Spectrum to you. Here's the story.

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Total votes 13: ↑11 and ↓2 +9
Comments 0

What happens behind the scenes C#: the basics of working with the stack

Reading time 6 min
Views 6.9K
I propose to look at the internals that are behind the simple lines of initializing of the objects, calling methods, and passing parameters. And, of course, we will use this information in practice — we will subtract the stack of the calling method.


Before proceeding with the story, I strongly recommend you to read the first post about StructLayout, there is an example that will be used in this article.

All code behind the high-level one is presented for the debug mode, because it shows the conceptual basis. JIT optimization is a separate big topic that will not be covered here.

I would also like to warn that this article does not contain material that should be used in real projects.

First — theory

Any code eventually becomes a set of machine commands. Most understandable is their representation in the form of Assembly language instructions that directly correspond to one (or several) machine instructions.

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Total votes 11: ↑10 and ↓1 +9
Comments 0

How to push parameters into methods without parameters in safe code

Reading time 4 min
Views 6.4K
Hello. This time we continue to laugh at the normal method call. I propose to get acquainted with the method call with parameters without passing parameters. We will also try to convert the reference type to a number — its address, without using pointers and unsafe code.

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Total votes 14: ↑13 and ↓1 +12
Comments 0

Writing a wasm loader for Ghidra. Part 1: Problem statement and setting up environment

Reading time 7 min
Views 11K

This week, NSA (National Security Agency) all of a sudden made a gift to humanity, opening sources of their software reverse engineering framework. Community of the reverse engineers and security experts with great enthusiasm started to explore the new toy. According to the feedback, it’s really amazing tool, able to compete with existing solutions, such as IDA Pro, R2 and JEB. The tool is called Ghidra and professional resources are full of impressions from researchers. Actually, they had a good reason: not every day government organizations provide access to their internal tools. Myself as a professional reverse engineer and malware analyst couldn’t pass by as well. I decided to spend a weekend or two and get a first impression of the tool. I had played a bit with disassembly and decided to check extensibility of the tool. In this series of articles, I'll explain the development of Ghidra add-on, which loads custom format, used to solve CTF task. As it’s a large framework and I've chosen quite complicated task, I’ll break the article into several parts.

By the end of this part I hope to setup development environment and build minimal module, which will be able to recognize format of the WebAssembly file and will suggest the right disassembler to process it.
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Total votes 18: ↑17 and ↓1 +16
Comments 1

PC Speaker To Eleven

Reading time 12 min
Views 34K
Known now as a «motherboard speaker», or just «beeper», PC Speaker has been introduced in 1981 along with the first personal IBM computer. Being a successor of the big serious computers for serious business, it has been designed to produce very basic system beeps, so it never really had a chance to shine bright as a music device in numerous entertainment programs of the emerging home market. Overshadowed by much more advanced sound chips of popular home game systems, quickly replaced with powerful sound cards, it mostly served as a fallback option, playing severely downgraded content of better sound hardware.

«System Beeps» is a music album in shape of an MS-DOS program that features original music composed for PC Speaker using the same basic old techniques like ones found in classic PC games. It follows the usual retro computing demoscene formula — take something rusty and obsolete, and push it to eleven — and attempts to reveal the long hidden potential of this humble little sound device. You can hear it in action and form an opinion on how successful this attempt was at Bandcamp, or in the video below. The following article is an in-depth overview of the original PC Speaker capabilities and making of the project, for those who would like to know more.

Total votes 34: ↑32 and ↓2 +30
Comments 3

System call interception in Linux-kernel module

Reading time 2 min
Views 10K

The module was created as a part of my master thesis in the 2010 year. The master thesis theme is Keylogging in Linux kernel. The main idea was to find out a way to intercept system calls for x64 arch Linux kernel, especially for kernel

Total votes 14: ↑13 and ↓1 +12
Comments 1

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