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.

A bar chart showing the number of viruses each month from March 2003 to February 2004. The vertical scale runs from 0 to 140 000. In March and April 2003, the bar is barely visible. It rises steadily to August 2003 (nearly 10 000) with a sudden peak in September 2003 (nearly 40 000). The figure then declines to around 7000 in December 2003 before suddenly surging in January 2004 to nearly 70 000 and in February 2004 to 115 000.

Figure 1: The number of viruses detected each month by the Open University's mail filter.

Last modified: Thursday, 2 August 2012, 12:30 PM