The second threat with computers is about passwords. Passwords is the only way to identify the user to the website or access to computers whether at home or in the corporate network. So it is important that you do not lose this password. If the password is stolen, or if anybody is able to guess your password, that person has complete access to all your files and network resources. By logging on with your password, a malicious intruder can read your e-mail, poke around in your sensitive files, access protected network resources such as corporate databases, and perform all sorts of mischief.

  Strong, effective passwords should be at least eight characters long and contain a random mix of uppercase and lowercase letters, numbers, and punctuation marks. A surprising fact is that most people do a poor job by using personal identification numbers, combinations of numbers and letters, such as birthdates or the names of children or pets which are easy-to-remember and easy-to-guess. To add to this agony, most people reuse the same password at every opportunity, which means that an intruder who steals the password for your favorite online bookstore might also be able to access your bank account, log on to your computer, and read or send messages using your e-mail account.

  Even the strongest password offers less protection if it's written on a sticky note and stuck to the side of a monitor or stuffed in the top desk drawer. Enterprising thieves also use "social engineering" to trick a gullible computer user into giving up passwords to a complete stranger over the phone or via e-mail. A con artist using social-engineering techniques might pretend to be a technical support specialist diagnosing trouble with your computer. By interspersing details about your company, its network, and your applications, the would-be thief tries to lull the victim into a false sense of security. Although the technique fails more often than it succeeds, it's still surprisingly effective. Even seasoned computer support professionals sometimes fall for social-engineering scams, in which an outside caller pretends to be a user experiencing password problems. On corporate networks, where individual users have access to a broad range of resources, the results can be devastating.

   Hence these kind of poor protection with poor passwords can be a security threat and is one of the common threat.