Keylogger Detection: How to Find and Remove Keystroke Loggers

Learn how to detect keyloggers before they steal your passwords and compromise your accounts.

Your antivirus didn’t catch it. Your firewall didn’t block it. But every password you’ve typed in the last three months just got sent to an attacker.

That’s the reality of keyloggers. They capture credentials silently, without triggering alerts. By the time you notice something’s wrong, your stolen passwords are already for sale on criminal marketplaces.

According to Mandiant’s M-Trends 2025 report, keylogging appeared in 4.1% of observed MITRE ATT&CK techniques. But here’s the bigger problem: 79% of intrusions last year were ‘malware-free’ because attackers simply logged in with stolen credentials.

This guide covers how to detect keyloggers and remove them. You’ll also learn how to protect your credentials after an infection.

What Is a Keylogger?

A keylogger does exactly what its name suggests. It logs your keystrokes.

Keyloggers fall into two categories: software and hardware.

Software keyloggers are malicious programs installed through phishing emails or drive-by downloads. They also come bundled with pirated software. They run invisibly in the background, capturing keystrokes at the operating system level.

Hardware keyloggers are physical devices. They plug inline between your keyboard and computer, or they’re built into modified keyboards themselves. These are rare in consumer attacks but appear in targeted corporate espionage.

The data keyloggers capture goes far beyond passwords. They record everything: private conversations and financial details. Proprietary business information too. Anything typed becomes attacker inventory.

How Do Keyloggers Work?

Software keyloggers use several technical methods to intercept your keystrokes before they reach applications.

API-Level Keyloggers

These hook into Windows API functions that handle keyboard input. When you press a key, the operating system processes it through standard functions. API keyloggers intercept these function calls and record the data before passing it along normally.

This approach is common because it’s relatively simple to implement. Most commercial keyloggers and off-the-shelf malware use API hooking.

Kernel-Level Keyloggers

Kernel keyloggers operate at the deepest level of the operating system. They intercept keystrokes before the operating system’s user-mode components even see them. This makes them extremely difficult to detect with standard antivirus tools.

Kernel keyloggers require elevated privileges to install. They typically arrive as part of rootkit infections or through exploited vulnerabilities.

Form Grabbers

Form grabbers don’t capture every keystroke. Instead, they wait for you to submit web forms and grab the data before it’s encrypted for transmission. This approach captures complete login credentials in context.

Form grabbers are a component of modern infostealer malware. They target banking sites and email logins. Corporate applications are prime targets too.

Memory Injection Keyloggers

These inject malicious code directly into legitimate browser processes. They capture data within the browser’s memory space, making them invisible to security tools monitoring system-wide activity.

Memory injection is technically advanced but increasingly common in commercial malware-as-a-service offerings.

What Are the Warning Signs of a Keylogger Infection?

Keyloggers are designed to operate invisibly. Well-crafted malware produces no obvious symptoms. However, less polished keyloggers often create detectable side effects.

Performance degradation is the most common indicator. If your system slows down when typing, or there’s noticeable lag between keystrokes and screen display, something may be intercepting your input.

Unusual network activity can signal data exfiltration. Keyloggers must transmit captured data somewhere. If your firewall logs show unexpected outbound connections, investigate.

Unexplained account compromises are the clearest sign. If accounts get breached without any phishing emails or password reuse, a keylogger may be capturing your credentials directly.

Unknown processes in Task Manager or Activity Monitor warrant investigation. Legitimate software has recognizable names. Random strings of characters or processes consuming resources when you’re not actively using applications suggest malware.

Browser extensions you didn’t install can contain keylogging functionality. Check your extensions regularly and remove anything unfamiliar.

How Do You Detect a Keylogger?

Detection requires systematic checking across multiple system areas. No single method catches everything.

Manual Detection Methods

Task Manager Review: Press Ctrl+Shift+Esc on Windows. Look for processes with unfamiliar names consuming CPU or memory. Google suspicious process names to identify legitimate software versus potential malware.

Startup Program Audit: Check what runs when your computer starts. On Windows, open Task Manager’s Startup tab. On Mac, check System Preferences > Users & Groups > Login Items. Remove anything you don’t recognize.

Browser Extension Check: Review installed extensions in each browser you use. Keyloggers often disguise themselves as productivity tools or ad blockers. Remove extensions you didn’t deliberately install.

Network Traffic Analysis: Tools like Wireshark or GlassWire show what your computer communicates with. Look for connections to unfamiliar IP addresses, especially those in regions associated with cybercrime.

Automated Detection Tools

Antimalware Scanners: Run full system scans with reputable security software. Use multiple scanners since each has different detection signatures. Malwarebytes and HitmanPro catch threats that traditional antivirus misses.

Rootkit Detection Tools: Standard scanners miss kernel-level threats. Dedicated rootkit detectors like GMER or TDSSKiller check for deeper infections.

Enterprise Detection Approaches

Security teams need scalable detection methods. Manual checking doesn’t work across thousands of endpoints.

Endpoint Detection and Response (EDR) solutions monitor process behavior across your environment. They flag suspicious keyboard API access patterns that indicate keylogging activity.

User Behavior Analytics identifies anomalies in how employees interact with systems. Sudden changes in typing patterns or login times can indicate compromised credentials.

Network monitoring at the perimeter catches data exfiltration. Security teams can identify command-and-control traffic associated with known keylogger families.

How Do You Detect a Keylogger on Your Phone?

Mobile keyloggers are harder to detect than desktop variants. They disguise themselves as legitimate apps and request accessibility permissions that give them keystroke access.

Android Detection

Check Settings > Apps for applications you don’t recognize. Pay attention to apps with accessibility permissions, which you can review under Settings > Accessibility. Any app with accessibility access can potentially log keystrokes.

Watch for unusual battery drain and higher than normal data usage. Your phone running hot when idle is another red flag. These indicate background processes sending data.

Review app permissions regularly. A flashlight app requesting accessibility access is a red flag. Uninstall anything suspicious and run a scan with a mobile security app like Malwarebytes.

iPhone Detection

iOS is more restrictive, making keyloggers less common but not impossible. Check Settings > General > VPN & Device Management for configuration profiles you didn’t install. Malicious profiles can enable keystroke monitoring.

Look for apps you don’t remember downloading. If your iPhone is jailbroken, you’re significantly more vulnerable since jailbreaking removes Apple’s security restrictions.

For both platforms, a factory reset is the most reliable removal method if you suspect an infection. Back up your photos and contacts first, but don’t restore from a backup that might contain the malware. After reset, change all passwords you entered on that device.

How Do You Remove a Keylogger?

Removal is straightforward once you’ve detected the infection. The harder problem is what happens next.

Removal Steps

1. Boot into Safe Mode: This prevents most malware from loading. On Windows, hold Shift while clicking Restart, then select Troubleshoot > Advanced Options > Startup Settings.

2. Run antimalware scans: Use your primary security software plus at least one secondary scanner. Different tools detect different threats.

3. Check installed programs: Look for recently installed applications you don’t recognize. Uninstall anything suspicious.

4. Review browser extensions: Remove unfamiliar extensions from all browsers.

5. Clear browser data: Delete cookies and cached data. Some keyloggers persist through browser storage.

6. Check scheduled tasks: Malware often creates scheduled tasks to reinstall itself. On Windows, open Task Scheduler and review all entries.

For severe infections, backing up essential files and reinstalling the operating system is the most reliable approach. This eliminates any persistence mechanisms the malware established.

Hardware Keylogger Removal

Physical keyloggers require physical inspection. Check the connection between your keyboard and computer. Look for inline devices that shouldn’t be there. In corporate environments, tamper-evident seals on USB ports can detect unauthorized access.

What Credentials Are at Risk After a Keylogger Infection?

Here’s what most detection guides miss: removing the keylogger doesn’t undo the damage.

Every password you typed during the infection period is compromised. That includes passwords for accounts you accessed and passwords you changed. If you reset a password while infected, attackers have both the old and new credentials.

Start credential rotation with these priorities:

1. Email accounts first. Password reset links for other services flow through your email. If attackers control your email, they can intercept resets for everything else.

2. Banking and financial accounts. These have the most direct monetary risk. Enable transaction alerts while you’re at it.

3. Corporate and work accounts. A compromised work login could affect your job and expose your employer to attack.

4. Password manager master password. If you typed it while infected, attackers can access your entire vault. Change it and rotate the passwords stored inside.

Stolen credentials follow a predictable path. They appear in stealer logs on dark web channels within hours of theft. Initial access brokers sort through the logs, identifying valuable corporate targets. Then they sell access to ransomware operators and other threat actors.

According to Mandiant M-Trends 2025, credential stealers made up 12% of malware observed in ransomware intrusions. That’s twice the rate seen across all intrusions. Ransomware operators specifically seek stolen credentials because they provide easy network access.

The timeline matters. You might remove the keylogger today, but attackers could use your stolen credentials weeks or months from now. Credential monitoring catches this exposure, alerting you when your passwords appear on criminal marketplaces.

How Do You Protect Against Keyloggers?

Prevention requires multiple layers of defense. No single control stops every keylogger.

Technical Controls

Keep software updated. Keyloggers exploit vulnerabilities to gain initial access and elevate privileges. Patching closes these entry points.

Use reputable antimalware with real-time protection. Signature-based detection catches known threats. Behavioral analysis catches novel malware.

Enable host-based firewalls to control outbound connections. Even if a keylogger installs successfully, blocking its exfiltration channel limits the damage.

Deploy EDR solutions in enterprise environments. They provide visibility into endpoint behavior that traditional antivirus lacks.

Authentication Hardening

Multi-factor authentication is your most important defense. Even if attackers steal your password, they can’t access accounts protected by MFA. Prioritize hardware security keys over SMS-based codes.

Password managers reduce keylogger impact. They autofill credentials without typing, bypassing keystroke capture. They also generate unique passwords for each account, limiting damage from any single compromise.

Behavioral Defenses

Verify software sources before installing anything. Download applications from official websites or trusted app stores. Pirated software is a common channel to distribute keyloggers.

Watch for malvertising and fake downloads. Attackers buy ads for popular software that lead to trojanized installers. Search results for “download [software name]” often include malicious sites. Go directly to vendor websites instead of clicking ads or search results.

Be skeptical of unsolicited links. Phishing emails still work, but attackers also distribute malware through Discord servers and social media. The common thread is urgency or too-good-to-be-true offers.

Post-Infection Monitoring

Detection and removal address the immediate threat. Dark web monitoring addresses the ongoing risk from already-stolen credentials.

When your credentials appear on criminal marketplaces, monitoring services alert you. You can reset those specific passwords before attackers exploit them. This closes the window between credential theft and credential abuse.

Conclusion

Keyloggers capture credentials silently. By the time you notice the symptoms, your passwords may already be circulating on dark web markets.

Detection means checking Task Manager for unknown processes and auditing startup programs. Review your browser extensions too. Automated tools help, but no single scanner catches everything.

Removal is the easy part. The harder challenge is addressing credentials stolen during the infection period. Every password typed while infected needs to be changed. Credential monitoring catches stolen passwords that surface on criminal marketplaces after removal.

The strongest defense combines prevention and detection with ongoing monitoring. Multi-factor authentication limits damage from stolen passwords. Antimalware stops known threats. Dark web monitoring catches credentials that slip through other defenses.

Check if your credentials are already exposed with a free dark web scan.