3-6-4 Internet Security

Virus- a computer virus is a computer program that can copy itself and infect a computer.

Infection Strategies:

• a true virus can spread from one computer to another, usually in some form of executable code, when its host program is taken to the target computer.
  
• this could be because a user sent it over a network or the Internet, or carried it on a removable medium such as a CD, DVD or USB drive.
  
• in order to replicate itself, a virus must be permitted to execute code and write to memory.
  
• for this reason, many viruses attach themselves to executable files that may be part of legitimate programs.
  
• if a user attempts to launch an infected program, the virus code may be executed simultaneously.

Spam

• Unsolicted junk emails
  
• usually advertising something
  
• spam wastes user's times

Worm:

• a computer worm is a self-replicating malware computer program which uses a computer network to send copies of itself to other computer on the network, sometimes without any user intervention.
  
• this is usually due to security shortcomings on the target computer. It is a network virus.

Worm vs Virus
Unlike a computer virus, a worm does not need attach itself to an existing program.

Worms almost always cause at least some harm to the network, even if only by consuming bandwidth.
Viruses almost always corrupt or modify files on a targeted computer.

Remote Log-in

• when someone connects to your computer without permission via the Internet
  
• this can lead to information being stolen/deleted.