What Is a Keylogger and Key Logging Software?

Hand pointing on lap top
Diego Lezama/Lonely Planet Images/Getty Images

A keylogger is a hardware device or a software program that records the real time activity of a computer user including the keyboard keys they press.

Use Cases for a Keylogger

Keyloggers are used in Information Technology (IT) organizations to troubleshoot technical problems with computers and business networks. Keyloggers can also be used by a family (or business) to monitor the network usage of people without their direct knowledge; they are sometimes used as part of home parental controls.

Finally, malicious individuals may use keyloggers on public computers to steal passwords or credit card information.

What Information a Keylogger Can Collect

The capabilities of keyloggers vary, but when installed on a device they can generally do the following:

  • capture any passwords entered by users on the device
  • take screen captures of the device at periodic intervals
  • record the URLs that were visited via Web browsers, and possibly also take screen captures of the Web pages viewed
  • record a list of the applications run by users on the device
  • capture logs of all instant messaging (IM) sessions
  • capture copies of sent emails
  • automatically send the reports containing stored logs and emails to a remote location (by email, FTP or HTTP).

Most keyloggers allow not only keyboard keystrokes to be captured but also are often capable of collecting screen captures from the computer. Normal key logging programs store their data on the local hard drive, but some are programmed to automatically transmit data over the network to a remote computer or Web server.

Where Keyloggers Come From and How to Determine if Your Device Has One

Some keylogger software is freely available on the Internet, while others are commercial or private applications. Keyloggers are sometimes part of malware packages downloaded onto computers without the owners' knowledge. Detecting the presence of one on a computer can be difficult.

By design, they hide their presence on a system via methods such as

  • being installed in hidden directories (folders) on the target system
  • cleverly disguising or hiding the application from the operating system task list (Windows Task Manager and Start screens, Mac OS Activity Monitor, and equivalent)

So-called anti-key logging programs have been developed to thwart keylogging systems, and these are often effective when used properly.

Choosing a Keylogger That's Right For You

Dozens of key logging systems can be found on the Internet through basic Web searches. If you're looking for a good keylogger solution for your home or business, consider these factors when making your decision:

  • Does it support the right operating systems?
  • Are the reports it generates easy to read and access?  Keyloggers that deliver nicely formatted reports to your mailbox are much easier to use than those who keep data scattered in strangely named files on a local hard drive.
  • How well does it remain hidden? If the keylogger hardware or software runs in plain sight, family members will likely find and disable it. If it consumes too many system resources (memory or processing power), it can also unnecessarily hamper the productivity of users.