Consider the following fragment of code in an authentication program:

username = read username(); password = read password(); if username is l33t h4ck0r return ALLOW LOGIN; if username and password are valid return ALLOW_LOGIN else return DENY LOGIN

What type of malicious software is this?

Backdoor

Explanation:

The back door fragment in a program allows user to access backdoor information without necessarily following the common security procedures needed. In this case, once the programmer keys in the username he or she logs in without putting password. Therefore, this is a backdoor fragment.