Cohen computer virus

Ryan described in The Adolescence of P-1 how an artificial intelligence spreads virus-like across the national computer network. It was hidden inside a larger, legitimate program, which was loaded into a computer on a floppy disk.

In , Fred Cohen published a demonstration that there is no algorithm that can perfectly detect all possible viruses. However, antivirus professionals do not accept the concept of benevolent viruses, as any desired function can be implemented without involving a virus. Any virus will by definition make unauthorized changes to a computer, which is undesirable even if no damage is done or intended. Before computer networks became widespread, most viruses spread on removable media, particularly floppy disks.

In the early days of the personal computer, many users regularly exchanged information and programs on floppies. Some viruses spread by infecting programs stored on these disks, while others installed themselves into the disk boot sector, ensuring that they would be run when the user booted the computer from the disk, usually inadvertently. Of course this should change with the advent of the internet. Then, the computer virus became a computer worm.

A computer worm is a standalone malware self replicating computer program that is supposed to spread to other computers via a computer network.

A computer worm relies on security failures on the target computer to access it. Unlike a computer virus, it does not need to attach itself to an existing program.

Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer. Pingback: Computer Virus-from Annoyance to a serious threat. Your email address will not be published. Related Posts. A year-old kid from Pennsylvania was one programmer who beat Cohen to the draw.

Rich Skrenta had a penchant for playing jokes on friends by spiking Apple II gaming programs with trick code that would shut down their computers or do other annoying things. In he wrote the Elk Cloner program -- a self-replicating boot-sector virus that infected Apple II computers through a floppy disk. Every 50th time the infected computer re-booted, a little ditty popped up:. Skrenta's program wasn't called a virus, since that moniker came later, nor did it spread widely outside his circle of friends.

That was left for the first virus spotted "in the wild" a couple of years later. The "Brain" was written in by two Pakistani brothers who claimed they only intended to infect IBM PCs running bootleg copies of a heart-monitoring program they created.

The virus included a copyright notice with the brothers' names and phone numbers so that people whose computers were infected could contact the brothers to obtain a "vaccination. Then in , Robert Tappan Morris Jr.

Unlike viruses, which are embedded in programs and copy themselves from system to system to unleash a payload, a worm can travel on its own without a carrier program, slithering through networks, searching for any connected system to infect with clones of itself, clogging the network as it spreads. It's been estimated that between 5 and 10 percent of all machines connected to the internet at that time -- most of them at universities or other research facilities -- were hit by the worm.

Morris was the first person to be tried and convicted under the Computer Fraud and Abuse Act of He was given three years probation and is now a professor at MIT. The growth of viruses and worms was fairly slow after this until the mids, when the proliferation of desktop PCs and e-mail usage opened the way for large-scale infections.

Viruses that previously relied on floppy disks and the "sneakernet" to spread, could now infect millions of machines with a little clever social engineering designed to trick users into opening infected attachments. The Melissa virus set the tone for fast-moving viruses in , reaching about , computers. Its payload was mostly innocuous, however.