What is a Keylogger?

Updated On - March 13, 2024

A Keylogger is typically a piece of malicious software that records every keystroke made on a computer, including passwords, credit card numbers, and sensitive personal information. Keyloggers can be installed on a computer without the owner's knowledge or consent and can remain undetected for long periods.

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Types of Keyloggers

There are two main types of keyloggers:

Software Keyloggers

Software keyloggers are a popular hacking tool that is installed on computers via infected application downloads. They operate by monitoring keystrokes on the host operating system, surreptitiously recording and transmitting them to a remote server controlled by the attacker. Hackers then harvest these keystrokes, including sensitive information such as passwords for email, banking, investment, and website accounts. The stolen passwords can unlock a wealth of personal information, facilitating further data theft or malicious activities.

Hardware Keyloggers

Hardware keyloggers, which require physical access to the target computer, pose a significant security threat. To mitigate these risks, organizations must strictly monitor access to devices and networks to prevent their unauthorized installation. These keyloggers capture and store sensitive information, which hackers can subsequently download. Notably, this data retrieval can only occur after the keylogging process is complete. However, certain advanced hardware keyloggers may be equipped with Wi-Fi capabilities, allowing hackers to remotely access and retrieve the sensitive data they have harvested.

How Keyloggers Work

Several techniques are employed for keylogging:

  • Video Surveillance: This method entails recording footage of the keyboard and computer screen. Keystrokes can be deciphered by slowing down and analyzing the playback.
  • Hardware Bug: Internal bugs can be planted within the keyboard itself to capture keystrokes. This is a covert and challenging technique to detect.
  • Physical Keylogging: A keylogger can be physically attached to the keyboard wiring or placed inside the computer, allowing it to intercept keystrokes as they pass through.
  • Software keyloggers: This approach involves installing software that replaces the keyboard interaction driver, positions a filter driver within the keyboard stack, or intercepts kernel or dynamic link library functions to capture keystrokes.
  • System Hook: This method involves intercepting keypress notifications by creating a system hook. Typically implemented in the C programming language.
  • Cyclical Information Request: Keystrokes are periodically retrieved from the keyboard using this technique. Common implementation languages include Visual Basic and Borland Delphi.
  • Filter Driver: A filter driver is installed within the computer to intercept keystrokes as they travel between the keyboard and applications. Typically developed using the C programming language.
  • Rootkits: These malicious software programs disguise themselves to evade detection. They can operate in user mode or kernel mode, making them particularly difficult to identify and remove.

How to Detect and Remove Keyloggers

Detecting keyloggers can be challenging, as they often run hidden and don’t exhibit any noticeable symptoms. However, there are a few things you can do:

  • Check for suspicious background processes: Use a task manager or system monitor to see if there are any unknown processes running.
  • Examine startup items: Look in the Windows startup menu or Task Scheduler for any suspicious programs that launch automatically.
  • Run a malware scan: Use an antivirus or anti-malware program to scan your computer for keyloggers.
  • Check for injected libraries: Some keyloggers inject themselves into legitimate system processes. Use a process explorer to check for any suspicious DLLs loaded into these processes.

To remove a keylogger, you can use antivirus software, anti-malware software, or specialized keylogger removal tools. It’s important to note that some keyloggers can be difficult to remove completely, so it’s recommended to seek professional help if you suspect your computer is infected.

How to Protect Against Keyloggers

There are several steps you can take to protect your computer against keyloggers:

  1. Keep software up to date: Install software updates promptly, as these often include security patches that can protect against keyloggers.
  2. Use strong passwords: Create complex passwords for all your online accounts and avoid using the same password for multiple accounts.
  3. Enable two-factor authentication: Use two-factor authentication to add an extra layer of security to your online accounts.
  4. Be cautious of emails and attachments: Don’t open attachments or click on links from unknown senders.
  5. Use a virtual keyboard: Some keyloggers can’t record keystrokes entered using a virtual keyboard.
  6. Install anti-keylogger software: Consider installing specialized anti-keylogger software that can detect and remove keyloggers.
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