What is a Keylogger? Keystroke Logging & How to Prevent It

Written by Hatice Ozsahan and David Worthington on July 20, 2023

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A shadowy intruder often lurks unseen, silently threatening your personal data’s sanctity. Meet the ‘Keylogger,’ a master of disguise, adept at eavesdropping on each keystroke you make. 

Your passwords, credit card details, and even your private conversations are fair game. So, how about a deep dive into the underbelly of the keylogger’s world? Let’s unravel the mystery together, dissect how it works, and arm ourselves with effective countermeasures like managing your endpoints and using phishing-resistance credentials. 

Hold onto your seats; it will be an enlightening ride into the world of keystroke logging and its prevention.

What is a Keylogger?

A keylogger, short for keystroke logger, is a type of surveillance software or hardware that records every keystroke made on a specific computer or network without the user’s consent or knowledge. This tool can capture and record all keyboard inputs, including but not limited to, passwords, usernames, emails, credit card numbers, and other sensitive information. While some legitimate uses exist for keyloggers, such as parental control or employee monitoring, they are often associated with malicious activities like identity theft, fraud, or spying.

Is Keylogger a Virus?

A keylogger, or keystroke logger, itself is not a virus but a type of software or hardware tool. However, it can be used maliciously and be part of a virus, Trojan, or other type of malware. When a keylogger is embedded in malicious software, it can be installed on a user’s device without their knowledge, often with the aim of collecting sensitive information like usernames, passwords, credit card details, and other private data. 

In this context, the keylogger operates much like a virus, hidden from view and working against the interests of the user. Therefore, while a keylogger isn’t a virus in itself, it can be a component of a virus or other malicious software.

How Does a Keylogger Work?

A keylogger works by monitoring and recording every keystroke on a computer or a network. Here’s a simplified explanation of how this process unfolds:

Installation

First, the keylogger must be installed on the target device. This can be done physically for hardware keyloggers (e.g., devices that plug into the keyboard or computer) or remotely for software keyloggers, typically downloaded as part of a malware package or via deceptive links.

Data Capture

Once installed, the keylogger begins to monitor and record all keystrokes made on the device. Some advanced keyloggers can also capture screenshots, track web browsing activity, record copied text on the clipboard, and even capture chat and email messages.

Data Storage and Transmission

The keylogger stores the collected data in a file, usually in an encrypted format for later retrieval. Software keyloggers may also send this data over the internet to a remote server controlled by the attacker. The transmission can happen at regular intervals or after a certain amount of data has been collected.

Data Retrieval

Finally, the person who installed the keylogger accesses the data, either by physically retrieving the device (in the case of a hardware keylogger), accessing the file on the computer, or by collecting it from the remote server.

The effectiveness of a keylogger depends largely on its ability to remain hidden from the user and any security software that may be installed on the device. For this reason, keyloggers are often designed to be difficult to detect, making them a potent tool in the hands of cybercriminals.

Hardware vs. Software Keyloggers

Both hardware and software keyloggers serve the same fundamental purpose – to record keystrokes on a device – but they differ in their methods of deployment, operation, and detection.

Hardware KeyloggersSoftware Keyloggers
InstallationPhysically connected to a computer’s keyboard and USB/PS2 port. Does not require any software or special privileges.Installed onto a system via deceptive downloads, email attachments, or by exploiting system vulnerabilities.
OperationStarts recording keystrokes as soon as the computer is turned on. Limited storage capacity for data.Can log keystrokes, take screenshots, capture clipboard data, record browsing history, and send data remotely to a server or email address.
Detection and RemovalHard to detect through software, but can be easily discovered during a physical inspection of the computer.Can be detected and removed by antivirus or antispyware programs, though some employ methods to avoid detection.

Hardware Keyloggers

Hardware keyloggers are physical devices that are typically connected between the computer’s keyboard and the USB or PS/2 port. Some advanced models are designed to be connected internally to prevent easy detection.

  • Installation: Hardware keyloggers are easy to install and do not require any software or special privileges on the system. They are simply plugged into the appropriate port.
  • Operation: These devices start recording keystrokes as soon as the computer is turned on. They have a limited storage capacity and can be accessed by the attacker physically removing the device and downloading the stored data.
  • Detection and Removal: Hardware keyloggers are typically hard to detect through software, as they don’t interact with the operating system or any software installed. However, they can be easily discovered during a physical computer inspection.

Software Keyloggers

Software keyloggers are malicious programs installed on a computer, often as part of a malware package.

  • Installation: Software keyloggers require a way to be installed onto a system, typically through deceptive downloads, email attachments, or by exploiting system vulnerabilities.
  • Operation: Once installed, software keyloggers can log keystrokes, take screenshots, capture clipboard data, and record other types of activity, such as browsing history. They can also send this data remotely to a server or email address controlled by the attacker.
  • Detection and Removal: Software keyloggers can be detected and removed by antivirus or antispyware programs. However, sophisticated keyloggers can employ various methods to avoid detection, such as rootkit functionality, disguising themselves as legitimate processes, or constantly changing their code to evade signature-based detection.

Software keylogger examples:

  • Spytector Keylogger
  • KidLogger
  • Ardamax Keylogger
  • Refog Keylogger
  • Elite Keylogger

Overall, software keyloggers are more common due to their versatility, ability to transmit data remotely, and their harder-to-detect nature compared to hardware keyloggers. Nonetheless, both types pose serious privacy and security risks and should be guarded against with appropriate security measures.

Is Keylogging Illegal in the US?

While keylogging, in and of itself, is not explicitly illegal in the United States, unauthorized utilization to infiltrate personal information on a computer can be construed as a breach of various federal and state laws. This may include the Electronic Communications Privacy Act (ECPA), with infractions potentially leading to stringent consequences, including imprisonment and heavy fines.

Contrastingly, there are instances where the employment of keyloggers is entirely lawful. These may involve diagnosing technical problems by IT professionals, insider threat surveillance in corporations, product enhancement research, and law enforcement activities, among others.

However, judging the legality of keylogger use isn’t a straightforward task and extends beyond user consent. It hinges on multiple factors, such as the ownership status of the monitored device and the intentions behind the keylogging sessions. Evaluating these aspects using a tripartite framework can be useful:

  • Consent: Did the user consciously consent, and was the user aware of the implications?
  • Ownership: Is the monitored device personally owned or company property?
  • Motive: Is the keylogging session driven by a legitimate cause or intended for unauthorized data access?

Despite the presence of legal applications, the bulk of keylogger use is often illicit, typically deployed clandestinely by cybercriminals with intentions of data theft. Therefore, maintaining strong cybersecurity measures and acting swiftly to remove any detected keyloggers is of utmost importance.

How do Hackers Use Keyloggers?

1. Distribution and Installation

Getting the keylogger onto the victim’s computer is the first step. This could be done through several means:

  • Phishing Emails: The hacker might send a deceptive email pretending to be from a trusted entity such as a bank, a service provider, or a colleague. This email might contain an attachment, for example, a seemingly harmless Word document or PDF, which installs the keylogger onto the system when opened.
  • Malicious Downloads: Hackers often hide keyloggers in software that appears legitimate or useful. For instance, they might offer a free version of a popular game or application on a sketchy website. When the user downloads and installs the software, they unknowingly install the keylogger as well.
  • Exploiting System Vulnerabilities: If a computer system or network has known security flaws that haven’t been patched, hackers can use these vulnerabilities to install keyloggers. For example, they could use an exploit in an outdated web browser to install the keylogger when the user visits a particular website.

2. Data Collection

Once installed, the keylogger begins recording keystrokes. For instance:

  • Capturing Passwords: The keylogger can capture the user’s keystrokes when they log into their online banking account, email account, or any other sensitive platform.
  • Recording Conversations: The keylogger can record entire conversations if the user uses the computer for instant messaging or email.
  • Collecting Credit Card Information: The keylogger can capture this information if the user makes an online purchase and types in their credit card details.

3. Data Transmission

After collecting this information, the keylogger needs to send it back to the hacker. This could happen in a couple of ways:

  • Email: The keylogger could be programmed to periodically send the recorded data via an email to the hacker.
  • Remote Server: The keylogger could send the recorded data to a remote server controlled by the hacker. This could be done in real-time or at specified intervals.

Remember, keyloggers can pose a serious threat to personal and financial information, so it’s crucial to maintain good cyber hygiene, such as keeping your software updated, avoiding suspicious emails and downloads, and using comprehensive security software.

How Can I Tell if I Have a Keylogger Infection?

Detecting a keylogger can be challenging, especially if it’s well-designed. However, there are several signs and methods to check if your system may be infected:

  1. Slow Performance: If your computer or internet is running slower than usual, it may be due to a keylogger using system resources or uploading data.
  2. Unusual Activity: Be wary of unusual error messages, unresponsive programs, or unexpected crashes. This could suggest the presence of malicious software, including keyloggers.
  3. Unexpected Disk Activity: An unexpected surge in disk activity could indicate that a keylogger is storing data on your hard drive.
  4. Monitor Network Traffic: Unusual outgoing network traffic, especially at times when you’re not using the internet, can be a sign of a keylogger.
  5. Use Anti-Malware Software: Regularly run a comprehensive anti-malware scan. Many modern anti-malware and antivirus solutions can detect a wide range of keyloggers.
  6. Use a Keylogger Detector: Some specialized software is designed specifically to detect keyloggers. These can be used alongside your primary security software.
  7. Check Running Processes: Use the Task Manager (Windows) or Activity Monitor (Mac) to check for unknown or suspicious processes. Note that advanced keyloggers may hide their presence.
  8. Hardware Inspection: If you suspect a hardware keylogger, physically inspect your computer for unknown devices connected between your keyboard cable and computer.

Remember, regular software updates, a reliable security solution, and safe online habits are your best defense against keyloggers. Always be wary of unexpected emails, and never download software from untrustworthy sources. If you suspect a keylogger has targeted you, consider consulting a cybersecurity professional.

Do Mobile Devices Get Keyloggers?

Yes, mobile devices such as smartphones and tablets can also be targeted by keyloggers. Just as they do with computers, keyloggers on mobile devices work to capture and record user input. This can include passwords, text messages, emails, and other sensitive information.

Mobile keyloggers can get installed on a device through various means:

  • Malicious Apps: An app downloaded from an unofficial source or even an official app store may contain a hidden keylogger.
  • Phishing Attacks: A mobile user might receive a text message or email with a link. Clicking on the link may lead to a malicious website that installs the keylogger onto the device.
  • Physical Access: If someone gets hold of the device and has enough time, they can manually install a keylogger.

Once installed, a mobile keylogger can monitor and log keystrokes, capture screenshots, track GPS locations, monitor calls and messages, and more.

To protect against mobile keyloggers, it’s advised to:

  • Download apps only from official app stores like Google Play Store or Apple App Store, and even then, only from trusted developers.
  • Regularly update the device’s operating system and all installed apps.
  • Be wary of suspicious messages or emails, especially if they include links.
  • Install and maintain a trusted mobile security app that can detect and remove malicious software.
  • Regularly backup important data.
  • Use strong, unique passwords, and consider using two-factor authentication whenever possible.

Best Methods for Detecting and Removing Keyloggers

1. Use Endpoint Detection and Response (EDR)

An EDR program is the cornerstone of your computer’s defense mechanism. It consistently scans your system for any kind of malicious software, including keyloggers, and removes them. It’s important to keep your antivirus software up-to-date because new threats emerge constantly. In addition, regular full system scans are crucial because they can catch malicious software that may have bypassed real-time detection.

2. Try Anti-Keylogger Tools

Besides your primary antivirus software, consider employing specific tools designed to detect and remove keyloggers. These tools focus on the behavioral patterns and signature profiles of keyloggers, making them an effective additional layer of security. Using anti-keylogger software in combination with an antivirus can help cover blind spots that a single program might miss.

3. Implement Firewall Monitoring

A computer’s firewall can serve as a valuable ally in detecting keyloggers. Firewalls monitor incoming and outgoing traffic from your computer, enabling you to spot unusual patterns or connections that might indicate a keylogger is sending data to an external source. Regularly checking your firewall’s logs and settings can help you identify potential threats before they cause serious damage.

4. Inspect Manually

Take the initiative to manually check your computer’s active processes from time to time. You can do this through Task Manager on Windows or Activity Monitor on Mac. Even though sophisticated keyloggers can hide their presence, a manual inspection can sometimes reveal lesser threats or irregularities in system behavior. Any suspicious or unknown processes should be investigated.

5. Look for Symptoms

Your computer’s behavior can often signal a potential threat. If your system starts to act slow, freeze unexpectedly, or crash, it could be infected with malware, including keyloggers. While these symptoms are not exclusive to keylogger infections, they are a good reason to run a full system scan and inspect your computer’s health.

6. Keep Things Up-to-Date

Keeping your operating system and all software up-to-date is a straightforward yet powerful way to keep keyloggers at bay. Updates often include patches for known security vulnerabilities that keyloggers and other malware could exploit. By neglecting updates, you leave your system exposed to threats, so it’s best to enable automatic updates when available and regularly check for new versions of your software.

7. Run a Physical Inspection

If you suspect a hardware keylogger, a physical inspection of your computer is necessary. Look for unfamiliar devices connected between your keyboard and computer or devices plugged into your USB ports that don’t belong. While hardware keyloggers are less common than their software counterparts, they are also harder to detect with software tools, making physical inspection a key step in your defense strategy.

To Remove a Keylogger:

If your antivirus or anti-keylogger software has detected a keylogger, follow the recommended steps provided by the software to quarantine and delete the threat.

For hardware keyloggers, physically unplug the device from your computer.

Remember, prevention is the best defense against keyloggers. Regular software updates, a reliable security solution, secure browsing habits, and skepticism towards unexpected emails or messages can significantly reduce the risk of keylogger infection. If you suspect a keylogger infection and the problem persists after following these steps, you may want to seek help from a cybersecurity professional.

How to Prevent Keylogging Attacks

Protecting yourself from keyloggers involves a mixture of good digital hygiene practices and using the right tools. Here are some practical steps:

1. Use Antivirus and Anti-Keylogger Software

Having a reputable antivirus and anti-keylogger program installed on your system is a must. These programs can actively scan for and remove malicious software. Make sure to keep these programs updated to protect against the latest threats.

2. Regular Software Updates

Always keep your operating system and all software up-to-date. Software updates often include patches that fix security vulnerabilities, reducing the risk of a keylogger exploiting those weaknesses.

3. Download Wisely

Only download software and apps from reputable sources. Avoid clicking on suspicious links, and don’t download attachments from unknown sources. Be particularly wary of freeware, as it can often come bundled with unwanted extras, including keyloggers.

4. Use a Firewall

A firewall can prevent unauthorized access to your system, stopping keyloggers from sending logged data back to the hacker. Review your firewall settings regularly and ensure it’s always enabled.

5. Beware of Phishing Attempts

Be cautious of emails, messages, or websites that ask for your personal information. Keyloggers can often be installed via phishing attempts that trick you into downloading malicious software.

6. Use Strong, Unique Passwords

While a keylogger can capture your passwords, using strong, unique passwords for each online account can limit the damage if one password gets compromised. Consider using a password manager to help manage multiple complex passwords.

7. Enable Multi-Factor Authentication

Multi-factor authentication (MFA) is a security protocol that requires users to provide two distinct forms of identification before gaining access to an account or system. This measure drastically enhances account security because even if a keylogger captures your password, the perpetrator still requires a second form of identification, which could be a unique code sent to your phone, a fingerprint, or a physical token. 

By adding an extra layer of defense, MFA makes it significantly more difficult for unauthorized individuals to access your information, thus providing a powerful deterrent against keyloggers and other forms of cyberattacks. It works even better for convenience and security when it’s phishing-resistant and users are working on manager devices.

8. Be Careful with Public Computers

When using a public computer, it’s critical to avoid entering any sensitive information whenever possible. This includes details such as credit card information, bank account credentials, social security numbers, and passwords. Keyloggers installed on these systems can record this sensitive information and transmit it back to cybercriminals.

Additionally, always remember to log out from any accounts you access, and clear the browser history, cache, and cookies when you’re finished. This eliminates residual data that could be exploited later. Also, avoid saving any login details when prompted by the browser, as these could be used to gain unauthorized access to your accounts in the future.

9. Monitor Your Attack Surface for Vulnerabilities

Your attack surface refers to the sum of all possible points where unauthorized access to your data can occur — this can include your hardware, software, network, and even the humans using the system. Monitoring your attack surface for vulnerabilities is a proactive approach that can significantly enhance your defense against keyloggers.

Perform regular vulnerability assessments using security tools that scan your network and systems for potential weaknesses. These tools can identify out-of-date software, misconfigurations, or other vulnerabilities that can be exploited by malicious software, including keyloggers.

Once identified, address these attack vectors immediately. This can involve patching software, adjusting configurations, strengthening firewall rules, or updating security protocols.

In the context of keyloggers, you should also check for physical vulnerabilities. Ensure all your hardware peripherals, such as keyboards and USB ports, are secure and not tampered with, as they can be targeted by hardware keyloggers.

In addition to automated scans, fostering a culture of security awareness amongst all users of the system is crucial. Educate users about the risks of downloading untrusted software, visiting dubious websites, or clicking on suspicious links.

10. Used Managed Devices for Work

You wouldn’t want your teenager’s computer to be used to access critical resources. Consider separating work and personal device use or adopt a comprehensive BYOD strategy. A managed device will be subject to meeting a security baseline and will be kept up-to-date. Identity and Access Management (IAM) systems can account for device state/trust and create policies that won’t permit unmanaged devices to access resources. It’s part of a Zero Trust strategy.

Get Started with JumpCloud

Deploying a cloud identity management solution helps streamline the process of securing endpoints and access control. The right cloud IAM solution helps you improve insider risk management with automation and ready-made compliance solutions. 

A modern cloud identity management solution like the JumpCloud Directory Platform empowers you to:

  • Securely connect employees to their devices (systems, mobile, servers), IT applications (on-prem or the cloud), files (cloud hosted or on-prem) and networks via VPN or Wi-Fi
  • Leverage best in class security using Zero Trust principles
  • Limit management overhead and improve security and user manageability 

All of these capabilities (and more) create a platform that connects users to virtually all of their IT resources regardless of provider, platform, protocol, or location, while also enabling admins to automate the onboarding and offboarding process and gain detailed visibility into all access transactions.

You can try JumpCloud for free to determine if it’s right for your organization. 

Our customers tell us that asset management is also important for security and IT operations. JumpCloud is enhancing its platform to unify SaaS, IT security, and asset management.

Hatice Ozsahan
David Worthington

I'm the JumpCloud Champion for Product, Security. JumpCloud and Microsoft certified, security analyst, a one-time tech journalist, and former IT director.

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