In the 1980s and 1990s Bulgaria had a blooming computer hardware industry specialized in providing large numbers of PCs for educational purposes. Thus, many schools and universities were provided with computers and computer science was a commonly studied subject. This helped foster a certain attitude about computers among that generation. In April 1988, Bulgaria's trade magazine for computers, Компютър за Вас, issued an article explaining in detail the nature of computer viruses and even methods for writing them. A few months after that, Bulgaria was "visited" by several foreign viruses, namely "Vienna", "Ping Pong", and "Cascade". The interest spawned by both the article and the viruses was huge, and soon young Bulgarian programmers began to search for ways to devise their own viruses. Soon a wave of Bulgarian viruses erupted, started by the "Old Yankee" and "Vacsina" viruses. Dark Avenger made his first appearance in the spring of 1989.
Viruses
Dark Avenger's first virus appeared in early 1989 and contained the string, "This program was written in the city of Sofia 1988–89 Dark Avenger". Thus, this first virus is usually referred to as "Dark Avenger", eponymous to its author. It was very infectious: if the virus was active in memory, opening or just copying an executable file was sufficient to infect it. Additionally, the virus also destroyed data, by overwriting a random sector of the disk at every 16th run of an infected program, progressively corrupting files and directories on the disk. Corrupted files contained the string, "Eddie lives... somewhere in time!"—possibly a reference to Iron Maiden's album Somewhere in Time. Due to its highly infectious nature, the virus spread worldwide, reaching Western Europe, the USSR, the United States, and even East Asia. It even received moderate mention in The New York Times and The Washington Post. Dutch authorHarry Mulisch reported having encountered the virus on his laptop while writing his magnum opus The Discovery of Heaven in his logbook on 21 October 1981 in the 51st chapter of the book, and because of his own and the book’s cabalistic nature, interpreted it as a “favourable sign from higher powers”, and subsequently considered it referring to the raven named Edgar which appeared in the corrupted scene of the book, and even considered naming his upcoming son Eduard, after the virus’ output ‘Eddie lives... somewhere in time’, though he eventually named him Menzo instead. A few weeks later, on 16 November he re-encountered the virus, and throughout 23–27 November he eventually had the virus professionally removed. This virus was soon followed by others, each employing a new clever trick. Dark Avenger is believed to have authored the following viruses: Dark Avenger, V2000, V2100, 651, Diamond, Nomenklatura, 512, 800, 1226, Proud, Evil, Phoenix, Anthrax, and Leech. As a major means for spreading the source code of his viruses, Dark Avenger used the then popular bulletin board systems. In its variants, the virus also contained the following strings:
"Zopy me – I want to travel"
"Only the Good die young..."
"Copyright 1989 by Vesselin Bontchev"
In technical terms, the most prominent feature of some of Dark Avenger's viruses was their polymorphic engine, the Mutation Engine ; MtE could be linked to the plain virus in order to generate polymorphic decrypters. Dark Avenger did not, however, invent polymorphism itself, since this had already been predicted by Fred Cohen and later put into practice by Mark Washburn, in his 1260 virus, in 1990. It wasn't until a year or more later that Dark Avenger's viruses began to employ polymorphic code. Dark Avenger made frequent attacks on Bulgarian anti-virus researcher Vesselin Bontchev. Such is the case with the viruses V2000 and V2100, which claim to have been written by Bontchev, in an attempt to defame him. This "conflict" between the two has led many to believe that Bontchev and Dark Avenger were intentionally "promoting" each other or that they might even be the same person. Dark Avenger's actions were not treated as a crime at that time in Bulgaria, since there was no law for information protection.
Identity
The identity of the person behind the pseudonym has never been ascertained. However, a lot can be inferred via various details of the viruses. Additionally, Dark Avenger was the subject of an interview conducted by Sarah Gordon which contains revealing information. Some of Dark Avenger's contemporaries, mainly Vesselin Bontchev, have also shed light on his potential identity. Dark Avenger may have been a fan of heavy metal music. The string Eddie lives...somewhere in time, which the virus outputs, draws attention. Eddie is the name of the mascot of the heavy metal bandIron Maiden. Additionally, Somewhere in Time is the title of the band's sixth album. Furthermore, in his interview with Gordon, Dark Avenger states that he named himself after "an old song"; Manowar have a song titled Dark Avenger, on their debut album. One of the viruses, Anthrax may have been named after a heavy metal band of the same name. Some hypothesize that Dark Avenger is Dr. Vesselin Vladimirov Bontchev due to the fact that a "Vesselin Bontchev" was mentioned in a 1989 virus by the Dark Avenger soon after Bontchev had written his doctoral thesis on computer viruses.
Interview with Sarah Gordon
One of the victims of Dark Avenger's viruses was Sarah Gordon, a computer security researcher. Gordon became intrigued with the virus and joined a virus-exchange Bulletin Board System in search of more information. Thus, she randomly came upon Dark Avenger, who was an avid visitor and BBS participant. The two came into contact and maintained it through e-mails for several years. Sarah Gordon later compiled most of these e-mails into a makeshift interview. The interview offers the best available insight into Dark Avenger's personality and motives, and it contains some valuable information. Dark Avenger had previously stated on several occasions that "destroying data is a pleasure". However, in this "interview", he confesses that he regrets his actions, and that they were not right. The degree to which Dark Avenger exposes himself to Gordon has led many to believe that he held a deep affection for her. He even went as far as devoting one of his viruses to her. It has been suggested by some virus writers that the Dark Avenger personality was a social experiment and Gordon was the object of a study herself, while helping build the myth. Others have hypothesized that Gordon herself was Dark Avenger.
