Morris worm was released on 2 November 1988 and by the following day was causing major problems for computers on the Internet. The worm quickly infected about 10 per cent of all computers connected to the Internet and, due to a programming error, made them unstable. In 1988 the Internet was made up of only 6,000 or so computers – it was an esoteric system used almost exclusively by government and academic institutions. But even so, it was one of the first warnings of the importance of applying security patches in a timely fashion.”]
Source: https://securelist.com/malware-calendar-wallpaper-for-may-2011/29797/