Whats is Keystroke logging.

Keystroke logging (often called keylogging) is the action of tracking (or logging) the keys struck on a keyboard, typically in a covert manner so that the person using the keyboard is unaware that their actions are being monitored. There are numerous keylogging methods, ranging from hardware and software-based approaches to electromagnetic and acoustic analysis.

Application

 

Software-based keyloggers

 

 

A logfile from a 

software-based keylogger.

A control window from a software-based keylogger.

These are software programs designed to work on the target computer’s operating system. From a technical perspective there are five categories: 

 

• Hypervisor-based: The keylogger can theoretically reside in a malware hypervisor running underneath the operating system, which remains untouched. It effectively becomes a virtual machine. Blue Pill is a conceptual example.
• Kernel-based: This method is difficult both to write and to combat. Such keyloggers reside at the kernel level and are thus difficult to detect, especially for user-mode applications. They are frequently implemented as rootkits that subvert the operating system kernel and gain unauthorized access to the hardware, making them very powerful. A keylogger using this method can act as a keyboard device driver for example, and thus gain access to any information typed on the keyboard as it goes to the operating system.
• API-based: These keyloggers hook keyboard APIs; the operating system then notifies the keylogger each time a key is pressed and the keylogger simply records it. Windows APIs on such as GetAsyncKeyState(), GetForegroundWindow(), etc. are used to poll the state of the keyboard or to subscribe to keyboard events.^[1] These types of keyloggers are the easiest to write, but where constant polling of each key is required, they can cause a noticeable increase in CPU usage, and can also miss the occasional key. A more recent example simply polls the BIOS for pre-boot authentication PINs that have not been cleared from memory.
• Form grabbing based: Form grabbing-based keyloggers log web form submissions by recording the web browsing onsubmit event functions. This records form data before it is passed over the Internet and bypasses HTTPS encryption.
• Memory injection based: Memory Injection (MITB)-based keyloggers alter memory tables associated with the browser and other system functions to perform its logging functions. By patching the memory tables or injecting directly into memory this technique can be used by malware authors who are looking to bypass Windows UAC (User Account Control). The Zeus and Spyeye Trojans use this method exclusively.
  
• Packet analyzers: This involves capturing network traffic associated with HTTP POST events to retrieve unencrypted passwords.

Remote access software keyloggers

These are local software keyloggers with an added feature that allows access to the locally recorded data from a remote location. Remote communication may be achieved using one of these methods:

• Data is uploaded to a website, database or an FTP server.
• Data is periodically emailed to a pre-defined email address.
• Data is wirelessly transmitted by means of an attached hardware system.
• The software enables a remote login to the local machine from the Internet or the local network, for data logs stored on the target machine to be accessed.

Hardware-based keyloggers

 

A hardware-based keylogger.

 

A connected hardware-based keylogger.

Main article: Hardware keylogger

Hardware-based keyloggers do not depend upon any software being installed as they exist at a hardware level in a computer system.

• Firmware-based: BIOS-level firmware that handles keyboard events can be modified to record these events as they are processed. Physical and/or root-level access is required to the machine, and the software loaded into the BIOS needs to be created for the specific hardware that it will be running on.
• Keyboard hardware: 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, typically inline with the keyboard's cable connector. More stealthy implementations can be installed or built into standard keyboards, so that no device is visible on the external cable. Both types log all keyboard activity to their internal memory, which can be subsequently accessed, for example, by typing in a secret key sequence.A hardware keylogger has an advantage over a software solution: it is not dependent on being installed on the target computer's operating system and therefore will not interfere with any program running on the target machine or be detected by any software. However its physical presence may be detected if, for example, it is installed outside the case as an inline device between the computer and the keyboard. Some of these implementations have the ability to be controlled and monitored remotely by means of a wireless communication standard..