Adware

• Displays advertising banners on web browsers
• Not always threatening
• Creates pop-ups
• Can cause sluggish network connectivity

Grayware

• Undesirable but less troublesome than malware
• Includes some spyware, adware and joke programs.

Malware

• Malicious Software
• Infiltrates or damages a computer system without the owner’s knowledge or consent
• Includes computer viruses, rootkits, spyware, and trojan horses

Rootkit

• Designed to take full control of a machine’s operating system
• Commonly encrypts files and demands payment to decrypt

Safe Mode

• Diagnostic mode for a computer operating system
• Reduces operating system functionality to a minimum
• Makes problem isolation much easier

Spyware

• Installs without the user’s knowledge
• Takes partial control of a machine
• Records personal information, such as surfing habits
• Actively redirects web browsers
• Secretly installs third party software

Trojan Horse

• Appears to be a legitimate,  desirable program
• Actually performs undisclosed malicious functions
• Most computer worms are trojan horses to hide the fact that access has been opened to intruders.

Virus

• Can copy itself and secretly infect a computer
• Can damage files
• Can open connections allowing others to control the machine

Worm

• Sends copies of itself to other machines on a network, often without user intervention.
• May only cause lowered bandwith as it spreads on the network
• Most commonly installs a back door to give someone access