Keylogger project, 5

05.11.2005 21:58


The software part of the keylogger is now almost finished. The only part that is missing is the serial EEPROM driver for which I need to make a new prototype board that has the actual EEPROM chip on it. I can't add it to the current board because the EEPROM is in a SMD package that can't be soldered to the breadboard.

It took me two days to debug the software for the transparent logging mode, but now it is working without problems. As far as I can tell it isn't detectable from software. The Linux kernel will still report that an ordinary AT keyboard is attached to it and the LEDs on the keyboard work as usual.

A simple menu is accessible by entering a correct (configurable) sequence of 8 keystrokes. Alphanumeric keys and also modifier keys like ALT and CONTROL can be used in this password, because the key logger saves it as sequence of raw scan codes. Of course all sorts of weird things happen if you activate the menu when some application other than a simple text editor has the keyboard focus. Because the keylogger has no way of getting feedback from the computer it will blindly type the menu text for example in a Firefox window which will then interpret the keystrokes as keyboard shortcuts and you will end with a messed up browser.

The bad news is that all this fancy code takes around 1800 bytes of code memory. This leaves only 200 bytes for the EEPROM driver and playback code, which most likely won't be enough. I guess it's time to look for a bigger 8051 compatible microcontroller. AT89C4051 looks promising since it's pin and code compatible with AT89C2051 I'm using now. I just hope I can get it in Slovenia for a reasonable price.

Posted by Tomaž | Categories: Digital

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