As you see, we can use key defs from input-event-codes.h Since we want a safe way to kill the loop safely (closing the stream and all) Printf("Key %d has been pressed\n", ev.code) fire when the event is EV_KEY and a key is pressed down Now that we have an event, we have to filter it to just * unsigned int value // 0 = released 1 = pressed 2 = repeated * unsigned short code // Key code in LKC standard (See bellow) * unsigned short type // Type of event, we are looking for EV_KEY * pressed we should have an event, events looks like this: * Now, if everything went as expected and a key is N = read(fd, &ev, sizeof ev) // Read from the buffer Our keylogger need to read every keystroke, so we will need to loop until break The code is written in C – pseudocode, so you have to make it fit in your system / standards, if it raises any question, just comment bellow, enjoy 🙂Ĭonst char *dev = "/dev/input/by-path/platform-i8042-serio-0-event-kbd" įd = open(dev, O_RDONLY) // Open the buffer Accessing the bufferĬ has lot of methods to do this, but I’ll use open(), read() and close from fcntl.h To check if this is what we are looking for, you can do $ cat /dev/input/by-path/*-kbd and type something, you should see the events coming, cool, it’s the keyboard buffer. In this case we aim to read the keyboard buffer (this has been done in Debian 8 Jessie, don’t know about other OSs), this buffer is in /dev/input, but, there is lot of them…well, in /dev/input/by-path you should have a *-kbd, this is a dynamic link to the actual keyboard buffer, so we will read from here. Have you ever heard “everything in linux is a file”?, well, it’s true, everything in linux, from pipes to buffers or PID’s is in a file somewhere, so we only need to read the correct file in order to get the info we want to have.
#HOW TO CODE A KEYLOGGER IN JAVA DRIVERS#
There are 2 “easy” ways to do this, modify the keyboard drivers or read the buffer, and this is exactly what we will do. This project has been written down for learning proposes and, of course it’s not intended to serve ‘evil’, so stay away from “muh code” if you are a 1337 h4x0r looking for scripts to steal someones privacy ¬¬įirst of all, if we want to log the keys pressed, we need to access to the keyboard, there are several ways of achieving this, you could say “if you are using C, stdin” but no, we want our script running in the background and stealing every key press no mater where it’s done, so we need to read directly from the hardware.
#HOW TO CODE A KEYLOGGER IN JAVA HOW TO#
Today we are going to talk about keyloggers, how does it work and how to build it in pure C. Long time since my last post, I’ve been kind of busy, but here we go again.
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