Social engineering is defined as a person who masquerades him or herself as an authorized figure in order to extract data from unsuspecting members of often a company or organization. Shoulder surfing, or the act of watching someone else as he or she uses a computer, most commonly in the form of peering over his or her shoulder, is a form of social engineering. People with clever eyes can piece together keystrokes and commit to memory usernames and passwords of their victim. The easier method of capturing keystrokes is with the use of a tool known as a keylogger. A multitude of keyloggers exist under free distribution on the Internet, and many of these programs have the ability to bind themselves to other applications and run silently, two ways that keyloggers often remain undetected. Sophisticated keyloggers can e-mail the attacker a log of all the keys the victim has pressed, as well as a screen capture of what they are currently viewing, as often as every minute, every hour on the hour, or every day. Hardware keyloggers can be implemented with physical access to the victim's computer system. The flash memory on the hardware keylogger captures every keystroke from the victim's keyboard and when enough data has been collected, can be easily removed from the victim's system. Hardware keyloggers are harder to detect, as most antivirus software detects a large percentage of the keyloggers advertised, but more difficult to put into place and remove, this hinging on whether or not the attacker has physical access to the victim's computer.