Intro: What a Keylogger is made of
Before we start programming, we need to answer a basic question: what is a keylogger? As the name implies (key+logger) - a keylogger is a computer program that logs (records) the keys (keyboard buttons) pressed by a user. This should be simple to understand. Lets say that I am doing something at my computer. A keylogger is also running (working) on this computer. This would mean that the keylogger is “listening” to all the keys I am pressing and it is writing all the keys to a log file of some sort. Also, as one might have guessed already, we don’t want the user to know that their keys are being logged. So this would mean that our keylogger should work relatively stealth and must not, in any case, show its presence to the user. Good, now we know what a keylogger as and we have an idea of its functions, lets move on to the next step.
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Basic Concepts: What needs to be achieved
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Ok, now lets plan our program, what should such keyloger do and what it should not. Significant difference to previous section is in the sense that here we shall discuss the LOGIC, the instructions that our program will follow.
Keylogger will:
1 - listen to all the key strokes of the user.
2 - save these keys in a log file.
3 - during logging, does not reveal its presence to the user.
4 - keeps doing its work as long as the used is logged on regardless of users actions.
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Implementation: Converting logic into code
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We shall use Visual Basic because it is much easier and simple to understand comparing to C++ or Java as far as novice audience is concerned. Although programmers consider it somewhat lame to code in VB but truthfully speaking, its the natural language for writing hacking/cracking programs. Lets cut to the chase - start your VB6 environment and we are ready to jump the ride!