What is a Computer Virus?

"A computer virus is a type of malware that, when executed, replicates itself by modifying other computer programs and inserting its own code into those programs. If this replication succeeds, the affected areas are then said to be "infected" with a computer virus, a metaphor derived from biological viruses.

Computer viruses generally require a host program. The virus writes its own code into the host program. When the program runs, the written virus program is executed first, causing infection and damage. By contrast, a computer worm does not need a host program, as it is an independent program or code chunk. Therefore, it is not restricted by the host program, but can run independently and actively carry out attacks."^[1]

The terms 'malware' and 'computer virus' do go together, but they don't mean the exact same thing. Malware serves as a broad, umbrella term that encompasses any type of malicious software, such as computer viruses, ransomware, worms, etc. All viruses are malware, but not every malware is a virus, because some may remain on a single device without replicating. However, i'll be including other types of malware here since they're similar, and because it's just fun :3

0 1 1 0 1 0 0 1 0 1 1 0 1 1 0 0 0 1 1 0 1
1 1 1 0 1 1 1 0 1 1 0 0 1 1 0 0 1 0 1 0 1
1 1 1 0 0 1 0 1 0 0 1 1 1 1 0 1 1 1 0 1 0
1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 0 0 0 1 0 0
1 1 1 1 0 1 1 1 0 1 1 0 0 1 1 0 0 1 0 1 0
1 1 1 1 0 0 1 0 1 1 0 1 1 1 1 0 1 1 1 0 1
0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 0 0 0 1 1
0 1 1 1 1 0 1 1 1 0 1 1 0 0 1 1 0 0 1 0 1
0 1 1 1 1 0 0 1 0 1 0 0 1 1 1 1 0 1 1 1 0
1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 0 0 0 1
0 0 1 1 1 1 0 1 1 1 0 1 1 0 0 1 1 0 0 1 0
1 0 1 1 1 1 0 0 1 0 1 0 0 1 1 1 1 0 1 1 1
0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 0 0 0
1 1 0 1 1 1 1 0 1 1 1 0 1 1 0 0 1 1 0 0 1
0 1 0 1 1 1 1 0 0 1 0 1 1 0 1 1 1 1 0 1 1
1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 0 0
0 1 0 0 1 1 1 1 0 1 1 1 0 1 1 0 0 1 1 0 0
1 0 1 0 1 1 1 1 0 0 1 0 1 1 0 1 1 1 1 0 1
1 1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 0
0 0 1 0 0 1 1 1 1 0 1 1 1 0 1 1 0 0 1 1 0
0 1 0 1 0 1 1 1 1 0 0 1 0 1 0 0 1 1 1 1 0
1 1 1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1
0 0 0 1 0 0 1 1 1 1 0 1 1 1 0 1 1 0 0 1 1

ILOVEYOU

"ILOVEYOU, sometimes referred to as Love Bug or Love Letter for you, was a computer worm that infected over ten million Windows personal computers on and after 5 May 2000. It started spreading as an email message with the subject line "ILOVEYOU" and the attachment "LOVE-LETTER-FOR-YOU.TXT.vbs." At the time, Windows computers often hid the latter file extension ("VBS," a type of interpreted file) by default because it is an extension for a file type that Windows knows, leading unwitting users to think it was a normal text file. Opening the attachment activates the Visual Basic script.

First, the worm inflicts damage on the local machine, overwriting random files (including Office files and image files; however, it hides MP3 files instead of deleting them), then, it copies itself to all addresses in the Windows Address Book used by Microsoft Outlook, allowing it to spread much faster than any other previous email worm."^[2]

"The virus arrives in an email with the subject line of "ILOVEYOU" with an attachment "LOVE-LETTER-FOR-YOU.TXT.vbs" that people were encouraged to open. The message body is "kindly check the attached LOVELETTER coming from me." The sender line will be the address it was sent from. The user must download and execute the worm by clicking on it.

The worm may also come from an infected computer on the same IRC channel using mIRC. The worm will be in an infected HTML document named LOVE-LETTER-FOR-YOU.TXT.HTM downloaded into the IRC downbloads folder. The user must access the .htm file to activate the worm.

Internet Explorer security settings do not allow scripts to access disk files and will display a warning when they try to. To work around this, the worm displays a message telling the user to give ActiveX control to the .htm file. If the user clocks on "Yes", the worm will infect the system. If the user clicks on "No", the worm reloads the message in an infinite loop until the user clicks on "Yes" to allow it to infect the system."^[3]

Happy99

Definitely my favorite piece of 'malware' of all time, mostly because it's hardly even malicious! "Lacking any destructve payload, Happy99 is not likely to ever cause any damage."^[4]

"Happy99 is an email/newsgroup worm that also behaves in some ways like a virus and trojan. It was created by Spanska and appeared in the 4th edition of the 29A virus magazine. Although Happy99 is wild, it has no destructive payload and is, as its author describes, a 'sympathetic hitchhiker who uses your internet connection to travel, and thank you for the trip with a small animation.'"^[5]