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.
