Define adware, spyware, and grayware 

Adware, spyware, and grayware are usually installed on a computer without the knowledge of the user. These programs collect information stored on the computer, change the computer configuration, or open extra windows on the computer without the user’s consent.

Adware
Adware is a software program that displays advertising on your computer. Adware is usually distributed with downloaded software. Most often, adware is displayed in a popup window. Adware popup windows are sometimes difficult to control and will open new windows faster than users can close them.

Grayware or malware
Grayware or malware is a file or program other then a virus that is potentially harmful. Many grayware attacks are phishing attacks that try to persuade the reader to unknowingly provide attackers with access to personal information. As you fill out an online form, the data is sent to the attacker. Grayware can be removed using spyware and adware removal tools.

Spyware
Spyware, a type of grayware, is similar to adware. It is distributed without any user intervention or knowledge. Once installed, the spyware monitors activity on the computer. The spyware then sends this information to the organization responsible for launching the spyware.

Phishing
Phishing is a form of social engineering where the attacker pretends to represent a legitimate outside organization, such as a bank. A potential victim is contacted via e-mail. The attacker might ask for verification of information, such as a password or username, to supposedly prevent some terrible consequence from occurring.