What is keylogging? How keyloggers work and how to protect yourself

Keylogging is the practice of secretly recording what you type on a keyboard, including passwords, messages, and card numbers, usually without the user’s knowledge. Attackers use a keylogger to capture that information and gain access to accounts, steal money, or commit identity theft.

Software and hardware keyloggers can reach your computer or mobile device through phishing emails, malicious downloads, compromised websites, or physical access. However, good security habits and layered protection can significantly reduce your risk.

Keylogging, also called keystroke logging, is the act of recording every key you press, often without your knowledge. The tool that does this, whether it’s software or a physical device, is called a keylogger or a keystroke logger.

Attackers target keyboards because that’s how people typically enter their most sensitive information, like usernames, passwords, and banking details. If a keylogger records keystrokes before they’re encrypted by your browser, it captures login credentials and other sensitive data in plain, readable form, which is what makes keylogging so effective for credential theft.

A keylogging attack usually progresses in three stages: device infection, activity recording, and data theft. Let’s see how each works:

An attacker presents something to you, such as a phishing email or a link to a compromised website. Inside that email, the keylogger may be disguised as a software update, a legitimate-looking download, pirated software, or a browser extension.

Once you click the link or install the file, the keylogger installs itself in the background without any pop-up or warning.

Once installed, the keylogger runs quietly in the background and records keystrokes across the operating system, capturing usernames, passwords, credit card numbers, messages, and authentication codes typed during login.

Some software keyloggers use form grabbing to pull data directly from web forms before it’s submitted, while others monitor keyboard input at a deeper, system-wide level so they can record keystrokes no matter which app or browser you’re using.

Captured data rarely stays on your device for long. Many software keyloggers send their recordings to a remote server controlled by an attacker, sometimes over encrypted channels that make it harder for security tools to catch.

Once a keylogger captures your login details, attackers can use them for account takeover, financial fraud, or identity theft. Worse still, that same information can fuel more convincing phishing scams later on.

Keyloggers fall into two broad categories: software-based and hardware-based.

Software keyloggers are malicious programs, often bundled with Trojans or other malware. They install directly on your operating system and run invisibly in the background.

Some of the most common software keyloggers include:

Instead of relying on malicious code, hardware keyloggers are physical devices that capture keystrokes directly from the keyboard.

Common examples include:

Because these devices require physical access to install, hardware keyloggers are usually seen in targeted attacks, such as on a shared office computer.

Keyloggers can be used for both malicious and legitimate purposes.

Cybercriminals use keylogging software to steal login credentials and financial data. They then use this information for:

Information captured by keyloggers can also make subsequent scams more convincing. Stolen credentials open doors, and what attackers find behind those doors fuels later attacks.

Legitimate uses of keyloggers include:

Whether these uses are legal depends on jurisdiction and user consent. Laws around employee monitoring, parental control, and other surveillance software vary widely, so it’s best to check local regulations before installing monitoring software on a device you don’t own.

Here are the biggest warning signs that can help you spot a keylogger:

Here are the best ways to protect yourself against keylogging:

Attackers often disguise keylogging malware as one of the following:

Avoid opening unexpected attachments or downloads, even from someone you know, and double-check suspicious messages and websites before entering sensitive login credentials. Once a keylogger captures those details, there’s often little time to react.

Monitor for new versions of your operating system, apps, and browser extensions. Update them as soon as they’re available.

Security updates patch vulnerabilities that attackers exploit to install malicious code, including keyloggers. If you keep running outdated software, those vulnerabilities stay open, and attackers get an easy way in.

Some common-sense steps can go a long way in limiting the impact of a keylogging attack. Keep these in mind:

Watch for the usual red flags associated with strange emails or pages:

If something feels off, don’t click or enter your login credentials until you’ve verified it.

Surfshark’s scam protection can do a lot of this checking for you, flagging things like:

The email checker can flag suspicious messages for signs of phishing or malicious links, while the web content blocker can filter website categories based on criteria like malware or phishing. Instead of detecting a keylogger that’s already installed on your device, this protection helps you avoid the phishing vectors that commonly lead to a malware infection in the first place.

Because software-based keyloggers are ultimately a form of malware, it’s vital to protect your device against malicious software.

Surfshark Antivirus detects and blocks malicious software before it can install a keylogger on your device, using real-time protection to scan files as you download or open them. It also runs scheduled or on-demand scans to catch suspicious programs, and its ransomware shield guards sensitive files against similar attacks.

Antivirus pairs naturally with Surfshark’s scam protection. Scam protection helps you avoid suspicious messages, links, and websites before you interact with them, while Antivirus catches malicious software that reaches your device anyway.

Credentials or personal information stolen via a keylogger can be exploited later, sometimes long after the initial infection. Here’s how:

To prevent such attacks, you can track your exposed details with data leak monitoring from Surfshark. It monitors your personal information for exposure in known data leaks, so you can respond faster if something is compromised by changing a password before an exposed account is misused and taking other corrective actions.

An unsecured connection is another way attackers can intercept your data. A VPN (Virtual Private Network) helps by encrypting your online traffic and hiding your IP (Internet Protocol) address.

While they can’t detect or remove keyloggers already on your device, tools like Surfshark VPN help protect your connection by making sure your data isn’t exposed to others on the same network while it transmits.

VPN protection is particularly helpful on public Wi-Fi. That said, since it protects your connection and not your device itself, consider it a secondary layer rather than your main defense against keylogging.

If you suspect or confirm a keylogger on your device, work through this checklist:

Removing the keylogger isn’t necessarily the end of the incident. Any sensitive information it has already captured could still be used for account takeover or further scams. That’s why it’s worth staying cautious afterward.

Keyloggers can silently capture passwords and other sensitive information. These often reach devices through phishing scams, malicious downloads, or compromised websites, and stolen data can lead to financial fraud or further scams.

Layered protection addresses each stage of the keylogging threat. Surfshark One brings several of these layers together, including scam protection, antivirus software, data leak monitoring, and more.