1.1 The growth of malware
The figures below show how the problem of malware has increased over the last 30 years.
|1974||First self-replicating code (Xerox)|
|1982||First virus on the Apple platform|
|1984||First conference papers on viruses presented|
|1986||First recorded virus infection on the PC|
|1987||First antivirus software|
|1990||400 viruses or variants|
|1996||8700 viruses or variants|
|1998||20000 viruses or variants|
|2003||80000 viruses or variants|
The term 'variant' is used to describe a virus that has been modified from the original in some way but is still basically the same virus. For example, the w32/sobig.a virus discovered in 2003 is the original virus and w32/sobig.f is a variant of the original.
Besides the number of different types of virus, the volume of viruses spread by email has grown enormously, as the following figure shows.