In 2024, the idea of a computer virus is nothing new, as these computer threats are, unfortunately, common enough. When it comes to cybersecurity, the idea of a computer virus is a major concern. Today’s concerns are a far cry from those 20-30 years ago when viruses were most likely to only target a small number of computers.
Unfortunately, computer viruses today are often developed to cause as much damage as possible. Thankfully, this wasn’t the case with the first computer virus. First developed in the late 1960s, the first computer virus arguably predates that of computer networks. The story of the first computer virus is fascinating, thanks to the work of just one person.
ARPANET
Before discussing the first computer virus, a little context will probably be helpful. For this purpose, it’s important to know about ARPANET. Standing for Advanced Research Projects Agency Network, this was one of the first computer networks that would eventually grow into the modern Internet.
ARPANET launched in 1966 and saw its first real-world use in October 1969. Bob Thomas, a computer engineer at BBN Technologies, was one of the individuals involved in this project. BBN was notably one of a few companies that played a critical role in its development.
It’s important to remember that when ARPANET was still being built, computers were still the size of bedrooms and not even close to being small enough to fit into a backpack. During this time, Bob Thomas started to think about what the world might be like with self-replicating computer programs. So, we have to thank Bob Thomas for the world’s first computer virus.
Creeper
To be 100% fair to Bob Thomas, the first computer virus, known as Creeper, wasn’t sent with any malicious intent. Instead, it was mostly a case of experimentation in whether or not code could be sent and loaded onto other systems.
In 1971, Bob Thomas designed Creeper to see if his thoughts about the potential for self-replicating programs were reality or a piece of fiction. However, Creeper wasn’t about self-replicating; instead, it jumped from one computer to the next.
Thomas wrote Creeper using a PDP-10 assembly and ran it on the existing TENEX operating system, a program that BBN developed in 1969. Using the ARPANET network, Creeper would jump onto a computer hard drive and display, “I’M THE CREEPER, CATCH ME IF YOU CAN!”
As soon as this message was displayed, the Creeper “virus” would start printing a file, stop midway through, and jump to another computer network on ARPANET. In other words, Creeper would leave the computer it was on and jump to another.
Enhanced Creeper
While the original Creeper “virus” wasn’t truly considered a “virus” as we know it today, the second version may be. Bob Thomas’s colleague Ray Tomlinson created a second, enhanced version of Creeper that self-replicated. Instead of jumping from one computer to another, it stayed on one system but replicated itself to another over the ARPANET network.
Thankfully, this enhanced version of Creeper wasn’t designed to be malicious, either. It was, again, an opportunity to see if Tomlinson’s theory about self-replicating code would work. The good news is that on the network Creeper “invaded,” it never had access to more than 28 machines.
In addition, the operators of these computers all had to permit this program to run, so they were all aware of Tomlinson’s test.
Reaper
While Tomlinson created the first self-replicating “virus,” he also helped create the first antivirus program. Codenamed Reaper, it was created to detect Creeper’s presence on ARPANET and delete any files related to its code.
Reaper was designed and run in 1972. It helped ensure that the Creeper program’s “infection” didn’t spread beyond Tomlinson’s initial intentions. For Tomlinson, this is just one of his many accomplishments, as he is also known as the individual who created the @ system to be used alongside email addresses.
Ultimately, Creeper and Reaper alike were relatively harmless all while paving the way for more advanced viruses that would almost certainly arrive in the coming decades.
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