Key logger (often called key logging) is a method of capturing and recording user keystrokes. Key logging can be useful to determine sources of errors in computer system, to study how users interact and access with systems, and is sometimes used to measure employee productivity on certain clerical tasks. Such systems are also highly useful for law enforcement and spying—for instance, providing a means to obtain passwords or encryption keys and thus bypassing other security measures. Key loggers are widely available on the Internet.
There are currently two types of key logging methods, hardware and software based.
Keystroke logging can be achieved by both hardware and software means. Hardware key loggers are commercially available devices which come in three types: inline devices that are attached to the keyboard cable, devices which can be installed inside standard keyboards, and actual replacement keyboards that contain the key logger already built-in. The inline devices have the advantage of being able to be installed instantly. However, while they may go unnoticed for quite some time, they are easily detected visually upon closer inspection. Of the three devices available, the most difficult to install is also the most difficult to detect. The device that installs inside a keyboard (presumably the keyboard the target has been using all along) required soldering skill and extended access to the keyboard to be modified. However, once in place, this type of device is virtually undetectable unless specifically looked for.types of keystroke loggers
1) Local Machine software Keyloggers are software programs that are designed to work on the target computer’s operating system. From a technical perspective there are three categories:
- Kernel based: This method is most difficult both to write, and combat. Such keyloggers reside at the kernel level and are thus practically invisible. They almost always subvert the OS kernel and gain unauthorized access to the hardware which makes them very powerful. A keylogger using this method can act as a keyboard driver for example, and thus gain access to any information typed on the keyboard as it goes to the Operating System.
- Hook based: Such keyloggers hook the keyboard with functions provided by the OS. The OS warns them any time a key is pressed and it records it.
- Creative Methods: Here the coder uses functions like GetAsyncKeyState, GetForegroundWindow, etc. These are the easiest to write, but as they require polling the state of each key several times per second, they can cause a noticeable increase in CPU usage and can miss the occasional key. However, skilled coders can overcome both these limitations by polling all key states several hundred times per second, while still not using more than 1% CPU usage to do so.
2) Remote Access software Keyloggers are local software keyloggers programmed with an added feature to transmit recorded data out of the target computer and make the data available to the monitor at a remote location. Remote communication is facilitated by one of four methods:
- Data is uploaded to a website or an ftp account.
- Data is periodically emailed to a pre-defined email address.
- Data is wirelessly transmitted by means of an attached hardware system.
- It allows the monitor to log into the local machine via the internet or ethernet and view the logs stored on the target machine itself.
3) Hardware Keyloggers are used for keystroke logging by means of a hardware circuit that is attached somewhere in between the computer keyboard and the computer. It logs all keyboard activity to its internal memory which can be accessed by typing in a series of pre-defined characters. A hardware keylogger has an advantage over a software solution; because it is not dependent on the computers operating system it will not interfere with any program running on the target machine and hence cannot be detected by any software.
4) Remote Access Hardware Keyloggers, otherwise known as Wireless Hardware Keyloggers, work in much the same way as regular hardware keyloggers. Except they have the ability to be controlled and monitored remotely by means of a wireless communication standard.
5) Wireless Keylogger sniffers collect packets of data being transferred from a wireless keyboard and its receiver and then attempts to crack the encryption key being used to secure wireless communications between the two devices.
6) Acoustic Keylogger work by analysing a recording of the sound created by someone typing on a computer. Each character on the keyboard makes a subtely different acoustic signature when stroked. Using statistical methods, it is then possible to identify which keystroke signature relates to which keyboard character. This is done by analysing the repetition frequency of similar acoustic keystroke signatures, the timings between different keyboard strokes and other context information such as the probable language in which the user is writing. A fairly long recording (1000 or more keystrokes) is required so that the statistics are meaningful.
Keylogger preventionCurrently there is no easy way to prevent keylogging. In the future it is believed that software with secure I/O will be protected from keyloggers Until then, however, the best strategy is to use common sense and a combination of several methods. It is possible to use software to monitor the connectivity of the keyboard and log the absence as a countermeasure against physical keyloggers. For a PS/2 keyboard the timeout bit (BIT6 at port 100) has to be monitored
simple way to say that this thing works like charmed even have screenshot what are u doing during it al have means that once it been install u cant hide wat are u doing.....
below is the link available to download key logger software...
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