At the beginning of the PC era, Internet security was not much of a concern as people simply booted their machines and loaded programs without worry.
In that earlier, more innocent era, the term "virus" was relegated strictly to the realm of clinical biology and only living things could actually get viruses. That all changed 30 years ago this month when University of Southern California graduate student Fred Cohen coined the term "computer virus."
The world's first computer virus had actually appeared a year before in 1982, with the debut of the Elk Cloner, which affected the Apple II operating system. For the first time in history, computers could now get "sick" with viruses, and the IT world has never been the same since.
Over the past 30 years, viruses have gone from that initial Elk Cloner virus, which had extremely limited impact, to widespread attacks that cripple companies and are now even part of the modern nation-state arsenal for cyber-warfare.
The timeline of viruses over the last 30 years has not been a straight line, and there have been multiple extinction events of entire classes of computer viruses as the IT industry has come to terms with virus threats. Roger Thompson, chief emerging threat researcher at ICSA (International Computer Security Association) Labs sees the past 30 years as being made up of multiple eras.
The first era was the age of DOS viruses which spanned from 1987 until 1995. Thompson described the period as one with "astonishingly complicated" code. One of the key evolutions during this period was the emergence of self-replicating viruses, known as worms.
On Nov. 2, 1988, Robert Morris, at the time a Cornell graduate student, unleashed the world's first worm. It was a 99-line program and was designed to infect Sun Microsystems and Digital Equipment Corp. VAX environments. In 2001, some 13 years after the Morris worm was unleashed, eWEEK ran on a story titled, "Who Let the Worms Out?" which detailed the impact that security incident had.
According to Thompson, the release of Windows 95 was an extinction-level event for the first era of viruses. Windows 95 introduced a new protected mode operating system, eliminating an entire class of viruses. At the same time, Microsoft introduced Office 95, which included a powerful macro language, which opened the door to a new era of the most destructive viruses that computing infrastructure had ever seen up to that date.
While the Morris worm was mostly a proof of concept, the Melissa worm of 1999 was not. Melissa was the first mass-mailing email virus and even 10 years after it first hit, eWEEK was still lamenting its destructive impact. Melissa's impact, however, pales in comparison to the devastation of the ILOVEYOU worm, which infected machines around the world in 2000.
The Melissa and ILOVEYOU viruses both overwrote and deleted files on millions of PC's worldwide. The worm component of Melissa and ILOVEYOU accessed users' contact lists in order to replicate and widely spread the destruction.
Melissa and ILOVEYOU were both macro viruses that leveraged Microsoft's Visual Basic scripting language in order to execute their destructive payloads. In April 2001, still reeling from the impact of ILOVEYOU, eWEEK reported that Microsoft restructured its entire security mantra in order to prevent a similar event from ever happening again. As it turned out though, the worst for Microsoft was yet to come.