An insecure computer or network presents a risk to the individual or organisation owning or running it. In common with many other fields in computing and computer science, viruses, worms, and the tools to detect them, have evolved a great deal indeed over the years.
Whilst some specialists in academic institutions were responsible for designing malicious programs between the 1950s and 1970s, it wasn’t until the early 1980s, with the growth of MS-DOS systems in the public domain that computer security began to impact upon the general public. In its original form, MS-DOS was relatively insecure, and as it grew in market share, so increased the malicious attacks on insecure DOS-based systems.
The growth of the internet, and the propagation of viruses and malicious code by e-mail, have led to an increase in the numbers and types of viruses and worms worldwide, and in parallel with this has developed a whole industry dedicated to virus detection, prevention and cure. Companies such as Norton, AVG and Mcafee offer a variety of free and purchased solutions, and will typically offer regular updates to their products, as and when new threats are discovered, to ensure that their protection remains strong and consistent. However, as virus protection has improved, virus writers have improved the sophistication of their methods to match, and a noticeable trend has been for the virus writer to make their work less obvious. In the past, viruses would tend to be accompanied by some on-screen display, perhaps to gain the writer some notoriety; however, the trend in more recent times has been to make any malicious code as invisible as possible, giving the computer owner all the more reason for virus protection to detect it.
Computer security can also take the form of physical security measures. These could include access security, where only permitted personnel are allowed into buildings, rooms, or to areas with insecure computers. These measures could also include locks on insecure computers, securing keyboards or other input devices from insecure access, and locks to prevent insecure computers from being removed from the premises.