Keylogger

What is a keylogger?

A keylogger (short for keystroke logger) is a type of monitoring software or hardware that records every keystroke a user makes on their keyboard. This data is then stored locally or sent to a remote server. The most common uses are:

• Illegal surveillance: Criminals often use keyloggers to steal passwords, credit card information or other personal data.
• Legitimate monitoring: Employers sometimes use keyloggers to monitor employee productivity, or parents to track their children’s online activities.

There are two main types of keyloggers:

• Software-based keyloggers: These are secretly installed on a computer and work at operating system level.
• Hardware-based keyloggers: These are physical devices that are placed between the keyboard and the computer and directly intercept the signals from the keyboard.

How do keyloggers work?

Software keyloggers work in the background and monitor every keystroke by either interacting directly with the operating system or intercepting the data by manipulating system drivers. Some are even able to take screenshots or monitor the clipboard. They can be particularly insidious as they are often disguised as harmless programs or embedded deep into the system. Hardware keyloggers are physical devices that are either plugged directly into the USB port between the keyboard and computer or sometimes even integrated into the keyboard itself. These devices record keystroke signals and store them on an internal memory chip until the attacker physically retrieves them or transmits them via a wireless interface (e.g. WLAN or Bluetooth).

Are keyloggers legal?

The legality of keyloggers depends heavily on the context:

• Legitimate use: Keyloggers may be used in companies to monitor the use of work devices, but only with the consent of the employees. This often falls under the Employee Monitoring Act or similar regulations, with data protection playing a central role.
• Illegal use: If keyloggers are used without the knowledge and express consent of the person being monitored, this is almost always a criminal offense. This applies to spying on passwords as well as private data and communication content.

How can I recognize a keylogger?

Keyloggers are often well hidden, but there are a few ways to detect their presence:

• Unusual system behavior: Is your computer suddenly slowing down with no apparent cause? This can be a sign of processes running in the background, such as a keylogger.
• Check running processes: Go to the Task Manager (for Windows) or the Activity Monitor tool (for MacOS) and check whether any unknown programs or processes are active there.
• Antivirus software: Many modern antivirus programs and special anti-malware tools such as Malwarebytes or Spybot detect keyloggers and similar malware.
• Network monitoring: Keyloggers often send data to remote servers. A tool such as Wireshark can help to identify suspicious data traffic.

How do I remove a keylogger?

A few steps are necessary to remove a keylogger:

• System scan: First carry out a full scan with a reputable antivirus software. It is best to use programs that also specialize in rootkits and spyware, such as Kaspersky, Bitdefender or Malwarebytes.
• Manual check: Check your installed programs and autostart entries. Remove unknown programs or those that appear suspicious.
• System reinstallation: In particularly severe cases, if the keylogger is deeply rooted in the system, it may be necessary to reinstall the operating system to ensure that all traces of the keylogger are removed.
• Firmware and BIOS updates: Some persistent keyloggers can even infect the BIOS or the firmware. In such cases, a firmware update helps to get rid of the malware.

Can a keylogger steal my passwords?

Yes, this is often the main purpose of a keylogger. A keylogger records all the inputs you make, including:

• Passwords for online banking, social networks and email accounts.
• Credit card information and other personal data.

It becomes particularly dangerous when the keylogger is combined with other malware components, such as a Remote Access Trojan (RAT), which gives the attacker direct access to your system.

How can I protect myself from keyloggers?

There are several effective protective measures against keyloggers:

• Up-to-date antivirus software: Always use well-rated and regularly updated antivirus software. These programs usually also offer real-time protection against keyloggers and similar threats.
• Anti-keylogger software: Special programs such as Zemana AntiLogger or SpyShelter offer additional protection against keyloggers.
• Two-factor authentication (2FA): Even if a keylogger records your password, attackers cannot access your accounts without the second factor (such as an SMS code or app confirmation).
• Virtual keyboards: You can use a virtual keyboard for particularly sensitive entries, such as passwords. This method can evade software keyloggers, as they are not able to capture screen inputs.
• Regular system updates: Always keep your operating system and all installed programs up to date to avoid security gaps.

Where are keyloggers frequently used?

Keyloggers are used in various scenarios:

• Cybercrime: Keyloggers are often used as part of phishing or malware campaigns to steal sensitive information such as login data or credit card numbers.
• Corporate monitoring: In some cases, companies use keyloggers to monitor employee productivity or to ensure that confidential information is not leaked.
• Parental control: Parents sometimes use keyloggers to monitor their children’s internet activity.
• Malicious hardware attacks: Hardware keyloggers can be installed, especially in public spaces such as Internet cafés or university computers, to monitor the input of unsuspecting users.

What are the signs that my computer is infected?

An infected computer often shows the following symptoms:

• System slowdown: Keyloggers often only consume a small amount of resources, but in combination with other malware components, your system can become noticeably slower.
• Unusual network activity: If you notice an unusual amount of data being sent over your network, it could be a keylogger sending data to an external server.
• Unknown programs: Find out whether new programs have been installed that you do not know. These could be part of a malware installation.

Are there differences between hardware and software keyloggers?

Yes, there are clear differences:

• Software keyloggers are programs that run on the computer itself. They often require installation by a user (e.g. via phishing or drive-by downloads). Their detection depends heavily on antivirus programs and their ability to identify malicious software.
• Hardware keyloggers are physical devices that are connected between the keyboard and the computer. This type of keylogger is particularly dangerous because they are often difficult to detect unless someone physically examines the computer.

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