Information Security | The infamous Friday the 13th virus

For those who grew up in the 80s, where the massification of Information Technology began, we heard a lot about viruses at the time, which had very different characteristics from current malware and, as we had, at the time, environments that were more disconnected than integrated, they aimed mainly at the attacked machine itself, without major losses in a scalable way (but this does not mean that there were also malicious programs at that time that had this function).

And taking advantage of Halloween, nothing better than rescuing one of the most popular viruses of that time, Friday the 13th, which was notorious in the 80s and 90s, where we will go through its origin, history, characteristics and curiosities of what was a precursor to malware , but which had a very different bias from what we currently experience.

Origin

The virus (originally called Jerusalem, but popularized as Friday the 13th) is one of many computer viruses that spread during the MS-DOS era and was created to activate itself. every Friday the 13th, according to the computer's system calendar (BIOS), taking advantage of the superstitions associated with that date and causing inconvenience to users.

History

Created in 1987, it was initially scheduled to spread on May 14, 1988, as a form of celebration (distorted, of course) of the 40th anniversary of the creation of the state of Israel.

This was a file virus, which infected executable files on the MS-DOS system. When an infected program was run, the virus activated itself. In general, the virus did not cause irreparable damage to data or hardware, but it was a source of irritation for users as it could affect the functioning of the system.

Characteristics

It spread by attaching its code to executable files, making them infected, having the ability to replicate and infect other files every time an infected program was run and spread mainly through floppy disks and by sharing files between computers.

When an infected floppy disk was inserted into a computer, the virus copied itself to the hard drive and from there infected other floppy disks used on the same machine. Likewise, when an infected program was shared with other users, the virus was spread.

The virus displayed humorous or threatening messages on the computer screen when activated, often as a trick to confuse or scare the user, and although it did not cause permanent damage, its presence could make the system slow and unstable.

While not particularly destructive, it could cause several unintended consequences for infected computers, including:

• System Instability: The virus had the potential to make the system unstable, causing frequent crashes and decreasing the overall performance of the computer
• On-Screen Messages: When activated, the virus displayed messages on the screen, some of which were threatening, while others were just bad jokes. This often scared or confused users
• Data loss: Although not its main purpose, the virus could cause file corruption and in some cases result in data loss if the affected files were important

Curiosities

• It was one of many malware threats circulating during the time when MS-DOS systems were popular
• Because security systems were less sophisticated back then, it was easier for viruses like this to spread
• Nowadays, most operating systems and security software are much more advanced in detecting and preventing malware, making these types of viruses practically harmless
• In order not to suffer from the virus's actions, it was recommended simply not to turn on the computer on this date, but more advanced versions of the malware were also activated the following day, generating its variant Saturday, 14

With the advancement of technology, the decline of the MS-DOS system, and the growing awareness of cybersecurity, viruses like Friday the 13th were gradually suppressed.

Modern operating systems are much more secure and include advanced protections against malware. Additionally, IT security practices and user education have evolved to help prevent malware infections.

Today, computer viruses are much more sophisticated and can pose real threats to the security of data and personal information. As a result, cybersecurity awareness and using up-to-date antivirus software are essential practices for protecting against online threats.

The Friday the 13th virus is an example of MS-DOS-era malware that did not cause significant damage, but was notable for its nuisance presence and ability to spread quickly between computers. However, thanks to advances in cybersecurity, threats like this have become less common and less harmful.

Overall, this was one of the early milestones of the cybersecurity movement (for both sides) and is part of the history of malware, being remembered as an example of the security challenges that IT systems faced in the 1980s and 1990s. However, it does not pose a significant threat in current times, thanks to progress in cybersecurity.

Below is an article from The New York Times at the time, portraying society's perception of this type of threat at that time:

https://www.nytimes.com/1989/10/08/business/the-executive-computer-friday-the-13th-a-virus-is-lurking.html.