Working for a safe, affordable, vibrant, innovative, and interconnected city.
Learn More Home Page This Department
Link to DoIT Home Page Link to DoIT Home Page Link to DoIT About Us Page Link to DoIT Contact Us Page
We make technology work for the City Michael Mattmiller, Acting Chief Technology Officer
Information Security Home Page
Chief Information Security Officer
Information Security Bulletins
Information Security Newsletter
Information Systems Security Policy
Spams and Scams
Creating Passwords
Securing Your Laptop
Protecting Your Home
Spyware Solutions
Wireless Network Security Solutions
Digital Consumer
Living Digital
Contact Us
Glossary of IT Terms

Information Security

Glossary A

This glossary contains industry standard and City specific IT terminology. The glossary should be consulted when policy, issue papers, etc. are drafted to ensure consistent use of terms across the City.

Virtual Private Network

Virtual Private Network - VPN
A Virtual Private Network - or VPN, is a network which emulates a private network, although runs over public network lines and infrastructure. Using specialist hardware and software, a VPN may be established running over the Internet. The use of encryption and a 'tunnelling protocol' maintains privacy. Because public networks are used, the cost of a VPN costs a fraction of that of a traditional private network.

A virus is a form of malicious code and, as such it is potentially disruptive. It may also be transferred unknowingly from one computer to another. The term Virus includes all sort of variations on a theme, including the nastier variants of macro-viruses, Trojans, and Worms, but, for convenience, all such programs are classed simply as 'virus'.

Viruses are a very real problem for both organization and individual computer users. At the present time there are very few, if any, virus which affect large computers, primarily because the programming languages which those systems use are not the same as those used to write virus code. Viruses, therefore are a problem primarily for users of PCs and servers.

As at January 2001, there were over 48,000 known viruses. Fortunately the great majority of these are classed as 'rare' and usually appear only in virus research centre files. However, that still leaves nearly 5,000 viruses, classed as 'common', roaming the world's computer networks, so there is absolutely no room for complacency.

They tend to fall into 3 groups:

  • Dangerous; - such as 'Resume' and 'Loveletter' which do real, sometimes irrevocable, damage to a computer's system files, and the programs and data held on the computer's storage media, as well as attempting to steal and transmit user ID and password information
  • Childish; - such as 'Yeke', 'Hitchcock', 'Flip', and Diamond, which do not, generally, corrupt or destroy data, programs, or boot records, but restrict themselves to irritating activities such as displaying childish messages, playing sounds, flipping the screen upside down, or displaying animated graphics
  • Ineffective - those, such as 'Bleah', which appear to do nothing at all except reproduce themselves, or attach themselves to files in the system, thereby clogging up the storage media with unnecessary clutter. Some of these viruses are ineffective because of badly written code, - they should do something, but the virus writer didn't get it quite right.

Within all types there are some which operate on the basis of a 'triggered event' usually a date such as April 1st, or October 31st, or a time such 15:10 each day when the 'Tea Time' virus activates.

Organizations should maintain a 'virus diary' of known high risk dates/times to ensure that anti-virus measures are in place as required.